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KOBE WELDING
2016-02-05 09:41:37

KOBE,WELDING CONSUMABLES

LB-52
4.0mm

 
 
 
 
 
A Quick Guide to Suitable Welding Consumables  for Mild Steel and 490MPa High Tensile Strength Steel
 

o   For Shielded Metal Arc Welding (SMAW)

 

Applications

Brand name*1

AWS classification

Features

 

 

 

 

Thin to medium plate joints

[F] RB-26

A5.1 E6013

Capable of vertical downward welding.

[F] Z-44

A5.1 E6013

Lower fume emissions.

[F] B-33

A5.1 E6013

Better bead appearance.

[F] B-10

A5.1 E6019

Deeper penetration than E6013.

[F] B-14

A5.1 E6019

Better X-ray soundness.

[F] B-17

A5.1 E6019

Higher resistance to hot cracking.

 

 

 

 

 

 

 

Thick plate joints

[F] LB-26

A5.1 E7016

For mild steel. Higher deposition rates.

[F] LB-47

A5.1 E7016

For mild steel. Better X-ray soundness.

[F] LB-52

A5.1 E7016

Typical electrode for 490MPa HT steel.

[F] LB-M52

A5.1 E7016

Extra-low hydrogen. Harmless fumes.

[F] LB-52A

A5.1 E7016

Extra-low hydrogen. HIgher resistance to cold cracking.

[F] LB-52UL

A5.1 E7016

Ultra-low hydrogen. Moisture resistant.

[F] LB-57

A5.1 E7016

Suitable for 520MPa HT steel. Extra-low hydrogen.

[F] LB-76

A5.5 E7016-G

Suitable for 520MPa HT steel.

[F] LB-52RC

A5.1 E7016

Suitable for HIC resistant steel.

[F] LB-52-18

A5.1 E7018

Higher deposition rates. Better usability with DCEP.

[T] LB-7018-1

A5.1 E7018-1

Higher deposition rates. Excellent low-temp notch toughness.

 

 

Horizontal and flat fillets

[F] LT-B52A

A5.1 E7018

Typical electrode for 490MPa HT steel.

[F] KOBE-7024

A5.1 E7024

Suitable for manual and gravity welding.

[F] LT-B50

-

Non-low hydrogen. Not suitable for thick sections.

 

 

 

 

Pipelines

[F] KOBE-6010

A5.1 E6010

Suitable for API grades of up to X52.

[F] KOBE-7010S

A5.5 E7010-P1

Suitable for API grades of X52-X60.

[F] KOBE-8010S

A5.5 E8010-P1

Suitable for API grades of X60-X70.

[F] LB-78VS

A5.1 E7048

Extra-low hydrogen. Vertical downward welding.

[F] LB-88VS

A5.5 E8018-G

Extra-low hydrogen. Vertical downward welding.

[F] LB-98VS

A5.5 E9018-G

Extra-low hydrogen. Vertical downward welding.

Root passes

[F] LB-52U

A5.1 E7016

Unsurpassed penetration bead appearance.

Tacking

[F] LB-52T

A5.1 E7048

Excellent re-arcing with a low hydrogen coating.

1. [F] designates FAMILIARC. [T] designates TRUSTARC.

 

 

Tips for successful welding results

 

1.  This guidance is to help users select appropriate welding consumables. Users are requested to confirm whether the selected brand can satisfy the job requirements before use.

 

2.  Suitable electric polarity for SMAW electrodes are as follows: AC, DCEN or DCEP for EXX13, EXX19, and EXX24; AC or DCEP for EXX16, EXX18 and EXX48; DCEP for EXX10. Wires for FCAW and GMAW use DCEP (DW-A51B uses DCEN). For SAW flux-wire combinations, AC is recommended. Electric polarity can affect the usability of welding consumables and the chemical composition and mechanical properties of weld metals; therefore, it is recommended to confirm the performance of the consumable you selected, using the polarity of a power source available for a particular job.

 

3.  The trade designations with a prefix of G or MF are fused-type fluxes for SAW, whereas those that begin with PF are bonded- type fluxes. The trade designations shown with a prefix of DW or MX are flux-cored wires, whereas those denoted with a prefix of MG or MIX are solid wires. Shielding gas composition can affect the usability of a wire, the chemical composition and mechanical properties of the weld metal.

4.  The mechanical properties of weld metals can be affected by preheat and interpass temperatures and welding heat input.

Therefore, these parameters must be controlled during welding to assure the weld quality.

 

5.  For details of individual brands, refer to KOBELCO WELDING HANDBOOK.

For Flux Cored Arc Welding (FCAW)

 

Applications

Brand name*1

AWS classification

Features

Shielding gas

Thin plate joints

[F] MX-100T

A5.18 E70C-6C/6M

Stable short-circuiting arc. Little slag.

CO2 or Ar+CO2

 

 

 

Medium plate joints

[F] DW-100

A5.20 E71T-1C

Higher deposition rates in all position welding.

CO2

[F] DW-100V

A5.20 E71T-1C

Higher deposition rates in vertical-up welding.

CO2

[F] DW-100E

A5.20 E71T-9C

Suitable for ship-class E-grade steels.

CO2

[F] DW-50

A5.20 E71T-1C/1M, 9C/9M

Suitable for ship-class E-grade steels.

CO2 or Ar+CO2

[F] DW-A50

A5.20 E71T-1M

Superior usability with low spatter.

Ar+CO2

[F] DW-A51B

A5.20 E71T-5M-J

Better crack resistance with DCEN. Basic-type flux.

Ar+CO2

 

Medium to thick plate joints

[F] MX-100

A5.20 E70T-1C

Higher deposition rates. Little slag.

CO2

[F] MX-A100

A5.18 E70C-6M

Higher deposition rates. Little slag.

Ar+CO2

 

 

 

Horizontal and flat fillets

[F] DW-200

A5.20 E70T-1C

Larger legs. Better bead appearance and shape.

CO2

[F] MX-200

A5.20 E70T-1C

Higher resistance to inorganic zinc primer.

CO2

[F] MX-A200

A5.20 E70T-1M

Higher resistance to inorganic zinc primer.

Ar+CO2

[F] MX-200E

A5.20 E70T-9C

Suitable for ship-class E-grade steels.

CO2

[F] MX-200H

A5.20 E70T-1C

Higher speeds on inorganic primer coated plates.

CO2

1. [F] designates FAMILIARC™.

 

o    For Gas Metal Arc Welding (GMAW)

o     

 

Applications

Brand name*1

AWS classification

Features

Shielding gas

 

 

Thin to medium plate joints

[F] MG-51T

A5.18 ER70S-6

Stable short-circuiting arc. All-position welding.

CO2 or Ar+CO2

[F] MG-50T

-

Stable short-circuiting arc. All-position welding.

CO2 or Ar+CO2

[F] MIX-50

A5.18 ER70S-3

Stable arc with lower currents.

Ar+CO2

[F] MIX-50S

A5.18 ER70S-G

Stable spray arc with higher currents.

Ar+CO2

 

Thick plate joints

[F] MG-50

A5.18 ER70S-G

Stable arc with higher currents.

CO2

[F] MG-S50

A5.18 ER70S-G

Superior usability and mechanical properties.

Ar+CO2

1. [F] designates FAMILIARC™.

 

o    For Gas Tungsten Arc Welding (GTAW)

 

Applications

Brand name*1

AWS classification

Features

Shielding gas

 

Thin to thick plate joints

[F] TG-S51T

A5.18 ER70S-6

Superior properties after long time PWHT.

Ar

[F] TG-S50

A5.18 ER70S-G

Suitable for Al-killed steels for low temp.

Ar

Root pass in pipe joints

[F] NO65G

A5.18 ER70S-2

More resistible to rusty surfaces.

Ar

1. [F] designates FAMILIARC™.

 

o    For Submerged Arc Welding (SAW)

 

Applications

Brand name*1

AWS classification

Features

Thin plate joints

[F] G-50 / [F] US-36

A5.17 F7A2-EH14

Suitable for high speed welding.

 

Thin to medium plate joints

[F] G-60 / [F] US-36

A5.17 F7A2-EH14

Suitable for high speed welding.

[F] PF-H45 / [F] US-43

A5.17 F6A4-EL8

Suitable for single or 4-5 multi-pass welding.

 

 

 

Medium to thick plate joints

[F] G-80 / [F] US-36

A5.17 F7A2-EH14

F6P2-EH14

Good performance in multi-pass welding.

[F] MF-38 / [F] US-36

A5.17 F7A6-EH14

F7P6-EH14

Better porosity resistance and X-ray soundness.

[F] MF-300 / [F] US-36

A5.17 F7A6-EH14

F7P6-EH14

Better slag detachability.

[F] PF-H55E / [F] US-36

A5.17 F7A4-EH14

Double-sided two-pass or multi-pass welding.

Horizontal and flat fillets

[F] MF-53 / [F] US-36

A5.17 F7A0-EH14

Better bead appearance and slag detachability.

 

1. [F] designates FAMILIARC.

 
 MG-51T shines in auto parts fabrication

 
 
 
(2) Much less spattering improves the welding environment and reduce downtime for remov- ing spatter on the weld — Figure 2.
 
$:6 $5.20 (717-1&
 
 
An unsurpassed rutile flux-cored wire for mild steel and 490MPa high tensile strength steel, which is highly reputed for solid ultimate performance.
 
Inception of DW-100
 
DW-100 was developed for welding mild steel and 490MPa high tensile strength steel and launched into the world of arc welding nearly 30 years ago. The prefix of the trade designation, DW, was coined from the words, Dual Wire, because the wire consists of steel sheath and cored flux. This development provided the momentum for ship- builders and bridge constructors in particular to employ semiautomatic and automatic welding with DW-100 instead of shielded metal arc welding with covered electrodes. This is why DW-100 is called an epoch-making flux-cored wire.
 
Outstanding features
 
The most remarkable features of DW-100 when used with CO2 gas shielding are the following.
 
(1) Adjusting once a certain proper welding cur- rent within a wide range of amperage and volt- age for each size of wire shown in Figure 1, there is no need to re-adjust the current posi- tion by position in all-position welding.
 
 
 
 
 
1.6PP‘
 
 
 
1.6PP‘
 
:HOGLQJ DPSHUDJH DQG YROWDJH
 
 
Figure 2: A comparison between DW-100 flux cored wire (FCW) and conventional solid wire (SW) on the amount of spatter in CO2 gas arc welding.
 
(3) Convenient self-peeling slag  removal  and glossy bead  appearance  reduce  postweld cleaning time — Figure 3.
 
 
 
 
Figure 3: Convenient self-peeling slag removal and glossy bead appearance with DW-100 in horizontal fillet welding.
 
(4) Regular bead profiles and smooth fusion with base metal — Figure 4.
 
 
 
 
 
 
40
1.2PP‘
 
30
 
 
1.4PP‘
 
1.6PP‘
 
 
 
 
20
 
 
10
 
 
100 200 300 400 500
:HOGLQJ FXUUHQW ($PS.)
 
Figure 1: Proper ranges of welding current and arc voltage for each size of DW-100.
 
Figure 4: Regular bead appearance and smooth fusion with the base metal in horizontal fillet welding with DW-100.
 
(5) High deposition rates can save labor costs by reducing welding time — Figure 5.
 
(6) Consistent mechanical properties of tensile strength and Charpy impact toughness of the weld metal — Table 1.
 
 
 
A variety of applications
 
 
 
&( 4PP‘
 
&( 5PP‘
  
&( 6PP‘
  
Nowadays DW-100 is used in various applications in such industries as shipbuilding, architectural structures, machinery, and bridges. Due to excel- lent usability, even an inexperienced welder can use DW-100 with satisfactory results. This usabil- ity includes stable wire feeding and tracking onto welding lines. DW-100 continually earns a high reputation from users in worldwide markets because of the services supported by the slogan, “QTQ” (Quality Products, Technical Support, and Quick Delivery) launched by Kobe Steel and the
 
150 200 250 300 350 400 450
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Kobelco group companies.
 
 
Figure 5: A comparison on deposition rates between DW-100 (FCW), conventional solid wire (SW) and covered electrode (CE) — wire extension: 25 mm, shielding gas: CO2.
 
 
Table 1: Typical chemical and mechanical properties of DW- 100 weld metal tested per AWS A5.20
 
C Si Mn P S
0.05 0.45 1.35 0.013 0.009
0.2% OS (MPa) TS (MPa) El (%) IV (J)
510 570 30 –18°C: 85
 
 
A leader of flux-cored wire
 
Since DW-100 was launched into the market, pro- duction of flux-core wires has ever increased. This is because of ever increasing consumption of flux- cored wires not only in shipbuilders and bridge constructors but also in other various industries throughout the world. Nowadays annual produc- tion of flux-cored wires in Japan has reached over 125,000 metric tons, accounting for about 35.5% as shown in Figure 6. Among flux-cored wires, DW-100 is one of the leaders.
 
 
 
 
 
DW-100 shines in various applications in such industries as shipbuilding, architectural structures, bridges and machinery.
 
New things in the traditional
 
During these three decades, DW-100 has seen its features  refined,  and  applications  expanded.  In order to maintain the outstanding features of DW- 100, the quality control in production is the very matter Kobe Steel stresses. DW-100 is a traditional flux-cored  wire,  but,  at  the  same  time,  highly advanced in that the quality of DW-100 has been
 
 
12.6%
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0.9%
(*7$: ZLUHV)
 
 
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14.1%
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maintained through advanced research and produc- tion engineering.
 
 
 
 
 
 
 
 
35.5%
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36.9%
(*0$: VROLG ZLUHV)
 
» Reference «
[1]  Statistic  News.  Welding  Technology,  Vol.  56,  4/2008,
Sanpo Publications Inc.
 
 
Figure 6: Annual production ratios of welding consumables in Japan in 2007 (Developed with data from Ref. 1)
 
 
 
 
 
 
 
 
 
 
$:6 $5.20 (707-1&
 
speeds for porosity in fillet welding. It clearly shows that MX-200 is far more resistant to shop primer than conventional rutile-type flux-cored wire and solid wire at a wide range of welding speeds.
 
 
 
MX-200 can release you from the headache of porosity in the fillet welding of shop-primer-paint- coated steel plates in horizontal and flat positions
 
Basic characteristics
 
MX-200 is a metal type flux cored wire suited for fillet welding of mild steel and 490 Mpa high ten- sile strength steel painted with shop primer. The M of the trade designation stands for Metal, while X reflects the expectation excellence. MX-200 was developed as an exclusive-use flux-cored wire for fillet welding in the horizontal and flat positions with CO2 gas shielding.
 
How shop primer causes porosity
 
Shop primer is a coat of paint applied to the sur- face of steel plates in order to protect them from rusting during a long fabrication period. Shop primer is often used in shipbuilding and bridge construction. Shop primer can be a predominant cause of porosity in fillet welds. Porosity is believed to occur because the arc heat decomposes shop primer into several gases and metallic vapors, which form pores in the weld metal. The degree of porosity depends on the type and coating thickness of the shop primer, the type of welding wire and welding parameters.
 
Advantages characteristics
 
A typical flux-cored wire can overcome the poros- ity problem caused by shop primer if the welding speed is reduced or if the shop primer is partly removed from where the fillet welds will be laid on.
 
However, if you need to do fillet welding much more effectively, using higher welding speeds and without removing shop primer, you will encounter the porosity problem.
 
Figure 1 shows the results of testing different types of  welding  wires  and  a wide  range  of  welding
 
 
 
 
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Figure 1: The results of testing the porosity resistance of MX-
200 in comparison with conventional rutile-type  flux-cored wire and solid wire in the fillet welding of shop-primer coated steel plates.
 
 
 
Besides better resistance to shop primer, MX-200 provides the following advantages:
(1) Glossy, smooth bead appearance due to thin, regular slag covering.
(2) Regular bead profile at a wide range of welding speeds due to excellent fusion at the toe of the fillet weld.
(3) Less spatters due to smooth droplet transfer.
(4) Smaller leg length (approx. 4mm) can be made more easily due to a stable arc at lower amper- age.
 
Figure 2 shows an example of bead appearance and a cross sectional profile of a fillet weld using MX-200. It shows smooth, regular bead appear- ance and regular leg length with proper penetration at the root of the fillet weld.
 
 
 
 
 
Figure 2: Bead appearance and cross-sectional macrograph of a fillet weld (MX-200, 1.2mmØ, 280Amp., 28-32volt, 50cm/min.)
 
 
 
 
In addition to excellent resistance against shop primer and unsurpassed usability, MX-200 is well- suited for high speed welding. Figure 3 shows the relationship between welding speed and leg length of fillet welds. You can determine the required welding speed for different leg lengths using this figure.
 
MX-200 can be used in automatic welding as well as semi-automatic welding. Figure 4 shows an example of an automatic welding process in which a portable fillet-welding carriage and MX-200 are used in fillet welding of longitudinal components in shipbuilding.
 
 
 
 
 
9 0;-200 (1.2PP‘)
 
 
8
 
 
7
 
 
6 280$
 
5
 
 
4
220$
 
3
 
 
 
30 40 50 60 70 80 90
:HOGLQJ VSHHG (FP/PLQ)
 
 
Figure 3: The relationship between welding speed and fillet leg length as a function of welding current.
 
 
 
Suitable for automatic welding
 
MX-200 persistently earns a good reputation among users in shipbuilding, bridge construction, machinery fabrication, railway-car fabrication, steel structure fabrication due to the outstanding features:
 
(1) Excellent resistant to shop primer
(2) Excellent usability
(3) Excellent high speed weldability
 
 
 
 
 
 
Figure 4: Fillet welding of longitudinal components by using a portable fillet welding carriage and MX-200 in shipbuilding (Photo courtesy of Tuneishi Shipyard, Japan).
 
Kobe Steel is sure MX-200 will provide you with efficient fillet welding at higher welding speeds and with increased mechanization in your work- shops.
 
 
 
 
 
 
 
 
 
$:6 $5.20 (707-1&
 
 
MX-100, the prototype of metal flux-cored wire, offers a softer arc, lower spatter, higher deposition rates, less slag, and more...
 
300
 
250
 
200
 
150
 
100
 
50
 
 
  0;-100
  &RQY. VROLG ZLUH
 
 
 
 
'LD: 1.2PP
([W: 25PP
 
 
 
 
 
 
'LD: 1.6PP
([W: 25PP
 
 
'LD: 2.0PP
([W: 30PP
 
 
 
Inception of MX-100
 
MX-100 was developed in 1985 as a metal flux- cored wire for CO2 shielded butt and fillet welding in the flat and horizontal positions. With its high deposition rate, low spatter and less slag, this development greatly improved the welding perfor- mance in semi-automatic, automatic and robotic welding of steel structures, industrial machinery and construction machinery.
 
 
 
 
 
MX-100 is an epoch-
 
0
200 300 400 500 600
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Figure 1: A comparison between MX-100 and conventional solid wire on deposition rate.
 
 
10
9
8
7
6
5
4
3
2
1
0
 
making metal flux-cored wire suitable for steel
 
&RQY. VROLG ZLUH
(1.2PP‘)
 
0;-100
(1.4PP‘)
 
structures, industrial
machinery and con- struction machinery.
 
 
Unsurpassed features
 
With the unique metal-rich cored flux, MX-100 is characterized by the following outstanding perfor- mance.
 
(1) HIGH DEPOSITION RATE: 10-30% higher
when compared with solid wire (Figure 1), which is beneficial to increase the welding speed and thus reduce the total welding cost as such.
 
(2) LOW SPATTER EMISSION: about one-half as low as that with solid wire (Figure 2) due to better arc stability and softer arc, thereby reducing postweld cleaning work on the weldments and the nozzle of the welding torch.
 
(3) LOW SLAG GENERATION: comparable to that with solid wire, which enables continuous multipass welding without removing slag on each pass in thick plates of up to 25mm.
 
Figure 2: A comparison of amounts of spatter deposited on the welding nozzle in robotic welding of one connection core (16t×350 sq. mm).
 
(4) CONSISTENT CHEMICAL AND MECHAN-
ICAL PROPERTIES: suitable for mild steel and 490MPa high tensile strength steel (Table 1).
 
 
Table 1: Typical chemical and mechanical properties of MX- 100 weld metal tested per AWS A5.20.
 
 
 
Table 1 shows the typical chemical composition and mechanical properties of MX-A100 weld metal tested in accordance with the AWS standard.
 
$:6 $5.18 (70&-60 Table 1: Typical chemical composition and mechanical prop- erties of MX-A100 weld metal with 80%Ar+20%CO2
 
MX-A100, a highly efficient metal-cored wire, offers
C%
Si%
Mn%
P%
S%
high deposition rates and low spatter emissions in 0.05 0.63 1.58 0.017 0.011
 
gas metal arc welding with an Ar-CO2  gas mixture
 
0.2% OS (MPa)
 
TS
(MPa)
 
El
(%)
 
IV (J)
 
shield in the flat and horizontal positions. Typical
applications are butt and fillet welding of mild steel and 490 MPa high tensile strength steel in indus- trial machinery and chemical engineering machin- ery.
 
Fundamental properties
 
The AWS classification for MX-A100 is E70C- 6M as per A5.18 (Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Weld- ing). This metal cored wire is intended for both single- and multiple-pass applications. It is charac- terized by a spray arc and excellent bead wash characteristics. The second designator 70 indicates the minimum tensile strength (70,000 psi or 483 MPa) of the weld metal tested according to the A5.18 specification. The third designator C stands
 
 
450 550 33 –40°C: 71
 
 
High productivity welding
 
MX-A100 runs with a stable and low spatter arc. The slag produced is of a very low level, similar to that from a solid wire, and thus inter-run slag removal is not necessary. Combined with a highly reliable arc start, these characteristics make MX- A100 an ideal choice for robotic or mechanized welding.
As shown in Figures 1 and 2, this wire offers a wide range of welding currents and high deposi-
tion rates, providing high welding productivity.
 
 
48
46
44
42
 
for “composite (including metal cored) wire.” The
suffix 6 indicates the chemical composition of the weld metal produced by the wire. The final suffix M indicates the type of shielding gas (75-80%Ar/ balance CO2) used for classification of the wire.
 
MX-A100 is also classified as EN ISO 17632-A-T
 
40
38
36
34
32
30 1.2PP ¡
28
26
24
22
20
18
 
 
1.4PP ¡
 
 
 
1.6PP ¡
 
42 4 M M 3 H5 in accordance with the European
Standard EN ISO 17632 (Tubular Cored Elec- trodes for Gas Shielded and Non-Gas Shielded Metal Arc Welding of Non-Alloyed and Fine- Grain Steels). “T” designates tubular cored elec- trodes, “42” is the code number associated with the tensile properties of the weld metal. The next “4”
 
50 100    150 200 250    300 350 400    450 500
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Figure 1: Recommended welding parameter ranges.
 
 
 
10
9
8
 
is also the code number related to the weld metal
impact toughness. The first “M” indicates the type of cored flux: metal powder. The second “M” des- ignates the type of shielding gas suitable for the
 
7
6
5
4
1.2PP ¡ 1.4PP ¡
 
 
1.6PP ¡ (([W: 25PP)
 
wire: gas mixture. “3” is the code number for the proper welding positions: flat butt, flat fillet and horizontal  fillet.  “H5”  designates  the  maximum
 
3 (([W: 20PP)
2
1
0
 
(([W: 25PP)
 
diffusible hydrogen content of the weld metal: 5 ml/100g.
 
50 100    150 200 250    300 350 400    450 500
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Figure 2: Deposition rates as a function of welding current.
 
 
 
 
 
$:6 $5.18 (70&-6&/60
 
circuiting  droplet  transfer  mode.  MX-100T  can
also use higher welding currents, covering a wide range of welding currents as shown in Figure 2.
 
 
 
The high performance metal cored wire MX-100T is an excellent choice for all-position welding of thin sections of mild steel and 490 MPa high tensile strength steel. It can use either a CO2 gas or an Ar+CO2 gas mixture for shielding. No more burn- through with a wide tolerance of welding currents
and speeds.
 
 
35
6ROLG ZLUH
30 ((5706-6, 1.2PP‘)
 
25
 
20
 
15
6ROLG ZLUH
 
 
 
 
 
 
 
 
 
0;-1007 (1.2PP‘)
 
 
 
More resistant to burn-through
 
Burn-through, which results in a discontinuity in weldments, is caused when the current is too high and welding speed too slow. In burn-through, a molten metal drops to the opposite side of the groove through the root of the welding joint. Burn- through is a common problem in sheet metal weld- ing. In general, to solve this problem, the welder may have to use smaller-size wires with lower welding currents and higher welding speeds. How- ever, higher welding speeds tend to cause an irreg- ular weld profile. By contrast, as shown in Figure 1, MX-100T allows to use higher welding currents or slower welding speeds than solid wires do, thereby resulting in superior weld bead appearance without burn-through.
 
((5706-6, 0.9PP‘)
0
100 200 300
:HOGLQJ FXUUHQW ($)
 
Figure 2: MX-100T features a wide welding parameter range covering those of 0.9- and 1.2-mm diameter solid wires.
 
Superior bead profiles
 
MX-100T offers smooth, regular bead profiles without undercut and overlap in all-position weld- ing as shown in Figures 3 and 4.
 
 
 
 
 
 
 
 
 
 
Figure 3: An MX-100T (1.2mmØ) lap fillet weld made on 2- mm thick steel sheets in horizontal welding (80 Amp.)
 
 
 
 
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1.0
 
 
 
0.5
 
 
 
 
 
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In addition to sheet metal welding in the auto, railroad vehi- cle and electrical appliance industries, MX-100T provides superior  weld  pro-
 
0;-1007 (1.2PP‘)
0
50 100 150 200
:HOGLQJ FXUUHQW ($)
 
files in the one-side root pass welding of
pipe joints fixed in
 
 
Figure 1: A comparison between MX-100T and solid wires on the welding current and speed limits in terms of burn-through.
 
Wider toleration of welding currents
 
MX-100T offers excellent arc stability at the lower welding currents (50-150A) needed for welding
 
the horizontal posi- tion.
 
 
 
 
 
Figure 4: An MX-100T (1.2mmØ) weld made on a 2-mm thick fillet joint in vertical downward weld- ing with an 80 amp current.
 
 
 
How to adjust weld penetration
 
 
 
 
 
$:6 $5 18 (5706-6
 
 
MG-51T: No.1 solid wire for gas metal arc welding in autos, motorcycles, containers and other sheet metal products. MG-51T uses either a CO2 or an Ar+CO2 gas mixture shield in all position welding.
 
It is important to control weld penetration in weld- ing sheet metals, because burn-through (excessive melt-through) often results in damaged welds. Although an excessive root opening and joint mis- alignment can also cause burn-through, an exces- sive welding current is more often the case. Figure 2 shows how to control weld penetration in rela- tion to welding currents.
 
 
Steady short-circuiting at low currents
 
Steady short-circuiting at low currents is the most valuable feature of MG-51T. If a general solid wire is used at low currents it may generate much spat- ter, undercut and irregular bead appearance due to unsteady short-circuiting in the molten metal trans- fer. In contrast, MG-51T offers low spatter and undercut generation with uniform bead appearance because of stable short-circuiting transfer of mol- ten droplets between the tip of the wire and the
 
 
6
Weld bead   Weld penetration
5
Base metal
4 0.9mmφ
 
3
 
2
 
1
 
 
 
 
 
 
 
 
 
 
1.2mmφ
 
molten pool. This outstanding feature is derived from the sophisticated design of chemical compo- sition and consistent quality surface of MG-51T.
 
How to create steady short-circuiting
 
Selection of proper welding current and arc volt- age is essential for creating a steady short circuiting arc, thereby facilitating all-position welding with MG-51T — Figure 1.
 
 
 
40
 
 
30
 
 
20
 
 
10
 
0
50 100 150 200 250 300 350
Welding current (A)
 
Figure 2: Weld penetration of MG-51T as a function of weld- ing current with a short circuiting arc.
 
Outstanding wire-feeding and
seam-tracking for higher welding efficiency
 
The smooth surface and consistent cast and helix of MG-51T wire provides steady wire-feeding through conduit liners and contact tips and enables exact seam-tracking along welding lines. This per- formance is good for decreasing downtime to improve welding efficiency in semi-automatic and automatic welding. Due to such benefits, MG-51T has seen the market expanded in the auto, motorcy- cle, container and other sheet metal industries.
 
 
 
0
100 200 300
Welding current (A)
 
 
Figure 1: Proper ranges of welding currents and arc voltages for MG-51T (0.9 and 1.2mmØ).
 
 
MG-51T is one of the most popular solid wires in the motorcycle indus- try.
 
 
 
MG-51T shines in auto parts fabrication
 
Typical applications in auto parts for MG-51T are frame assembly, lower and upper arm, axle beam, axle housing, torque converter, impact beam, bumper reinforcement, suspension member (cross member), instrument panel reinforcement, and seat frame, as included in Figure 4.
 
 
 
 
 
 
 
Seat frame
 
 
 
 
 
Suspension member
 
 
 
 
Seat rail
 
Axle housing
 
 
 
 
 
Radiator
 
 
 
Instrument panel reinforcement
 
Steering rod
 
 
Rear suspension
 
 
 
Bumper
 
 
 
Lower arm
 
 
Wheel
 
 
 
 
 
 
Front suspension Trailing arm
 
 
 
 
Frame assembly
 
Torque converter
 
 
 
Axle beam
 
 
 
Exhaust system
 
 
Manifold system
 
 
Muffler system
 
 
 
 
 
 
 
 
 
 
 
Arm
 
 
 
 
 
Figure 4: Varieties of auto parts where gas metal arc welding is applied.
(MG-51T is used for welding parts of mild steel and 490 MPa high tensile strength steel)
 
 
 
 
 
 
 
 
 
$:6 $5.1 (6013
 
 
RB-26 is the traditional and advanced covered elec- trode for all-position welding (including vertical downward position) of mild steel sheets.
 
Inception of RB-26
 
RB-26 is a high titania type covered electrode for welding mild steel. It was developed in 1951. The R in “RB” stands for rutile, which is the major ingredient in the coating flux, while “B” symbol- izes a slag-shield covered electrode. “26” repre- sents the 26th year of the Showa era of Japan, corresponding to 1951 when it was developed.
 
Is RB-26 old-fashioned?
 
You may believe that RB-26 is old-fashioned due to its inception. RB-26, however, is commonly used worldwide for welding light sheet metals and light-gauge formed steel in light-duty steel struc- tures, and for surfacing thick-section welds to improve rough surfaces (the surface dressing tech- nique). The consumption of RB-26 differs country by country. In Southeast Asia and the Middle East, RB-26 is one of the most commonly used, contem- porary electrodes.
 
RB-26 is superior to other E6013 electrodes on performance
 
RB-26 persistently earns a good reputation among users due to the following outstanding features in out-of-position welding including the vertical- down position:
 
(1) Smoother arc transfer
(2) Less spatter
(3) Self-peeling slag removal (Figure 1)
(4) Smoother bead surfaces with fine ripples
(5) Excellent fusion with base metals provides a longer bead per one electrode — advantageous in welding sheet metals
(6) Consistent chemical composition and mechani-
cal properties (Table 1)
 
 
 
 
 
 
 
Figure 1: Convenient self-peeling slag removal with RB-26 assures a glossy bead appearance without postweld brush- ing.
 
 
Table 1: Typical chemical and mechanical properties of RB- 26 weld metal tested per AWS A5.1
C% Si% Mn% P% S% 0.08 0.30 0.37 0.012 0.010
YP (MPa) TS (MPa) El (%) 450 510 25
 
 
How RB-26 is of international
 
Kobe Steel has established a worldwide production and sales network in order to assure quicker deliv- ery and technical services matching local demands for RB-26. This electrode is now mainly produced by Thai-Kobe Welding Co., Ltd. in Thailand in accordance with the Kobe Steel quality standard, and is sold not only in the Thai domestic market, but also exported to other countries including Saudi Arabia, Vietnam, and Singapore. RB-26, among all the various brands classified as E6013, has persistently earned high reputation for the quality, delivery and technical service in these international markets.
 
Committed to quality and customer satisfaction
 
The high quality of RB-26 produced in both Japan and overseas is approved and certified by the ship classification societies of Nippon Kaiji Kyokai (NK), American Bureau of Shipping (AB) and Lloyd's Resister of Shipping (LR) — Table 2. These approvals and certificates will be reliable to users on the quality of RB-26.
 
 
Table 2: Ship classification approvals for RB-26
 
AB LR NK
2 2m KMW2
 
 
 
 
Further, the emphasis on quality pervades the fac- tories in Japan and overseas — with nearly all of our employees involved in quality control circles. To ensure RB-26 is defect-free, we inspect it piece by piece (Figure 2) and lot by lot of production by using Kobe Steel’s proprietary inspection pro- cesses and procedures (Figure 3).
 
 
 
 
Figure 2: To ensure the appearance quality of RB-26, elec- trodes are inspected piece by piece in accordance with Kobe Steel’s standard (at Thai-Kobe Welding).
 
 
 
 
Figure 3: In order to ensure the quality of RB-26, the dimen- sions of the electrodes are inspected lot by lot by using Kobe Steel's proprietary inspection procedures (at Thai-Kobe Weld- ing).
 
In 1999, Thai-Kobe Welding became the first welding consumables manufacturer in Thailand to achieve JQA ISO 9002 certification for customer satisfaction. Further the latest precise inspection
 
equipment (Figure 4) has strengthened the quality control activities to maintain the traditional high quality.
 
 
 
 
 
 
Figure 4: Computerized system strengthens quality control activities (at Thai-Kobe Welding).
 
To ensure customer satisfaction, the marketing staffs work closely with customers and end users, providing technical services that include training in welding techniques. Unsurpassed quality of RB- 26 and customer satisfaction remain our highest priorities.
 
Something new in the traditional
 
Since its inception, RB-26 has seen its features refined and its markets expanded. Kobe Steel pur- sues keen quality control in order to maintain the outstanding features of RB-26 produced in Japan and overseas. RB-26 is a traditional covered elec- trode, but, at the same time, highly advanced in that the quality of RB-26 has been maintained through advanced research and production engi- neering. Kobe Steel hopes RB-26 will be an indis- pensable electrode for your workshops.
 
 
 
 
Water tanks with a thin section are often fabricated with RB- 26 in Thailand.
 
 
 
Excels in Melt-Through Root-Pass Welding
 
 
 
 
$:6 $5.1 (7016
 
 
 
LB-52U (E7016) is an unsurpassed covered elec- trode for melt-through root-pass welding, or one- sided root pass welding with penetration beads. With  LB-52U  your  welding  will  be  easier  and
 
Table 1: Typical chemical and mechanical properties of LB- 52U weld metal
C% Si% Mn% P% S% 0.07 0.55 1.05 0.011 0.006
 
faster, and you will have confidence in the quality
 
of your welds in any kind of pipe welding of mild steel  and  490MPa  high  tensile  strength  steel.
 
0.2% OS (MPa)
 
TS
(MPa)
 
EL
(%)
 
IV
(J)
 
[H]d*1
(ml/100g)
 
480 560 31 –29°C: 80 3.5
Described  here  are  the  characteristics  that  have
 
made LB-52U the best for one-sided pipe welding.
 
(1) EXCELLENT USABILITY IN ALL-POSI- TION WELDING
 
LB-52U features a very stable arc and low spatter over a wide range of welding currents. In particu- lar, it really shines in the melt-through root-pass welding of horizontally fixed pipes due to the smooth, glossy penetration beads that protrude on the reverse side of the groove (Figure 1) and the wider tolerance of the root opening — an advan- tage in site welding.
 
 
 
 
Figure 1: The surface and macrosectional profiles of a pene- tration bead protruding on the reverse side of a single-V- groove weld.
 
(2) SUPERIOR CRACK RESISTANCE AND MECHANICAL PROPERTIES
 
LB-52U offers superior crack resistibility due to a lower amount of diffusible hydrogen in the weld metal. In addition, it excels in mechanical proper- ties, particularly in impact strength at low tempera- tures (Table 1). Therefore, it can be used for low- temperature applications as well as moderate high- temperature applications.
 
1. Diffusible hydrogen in the weld metal made in the welding atmo- sphere of 21°C × 10%RH (Gas-chromatographic method)
 
 
(3) FIELD-PROVEN ELECTRODE IN WORLD- WIDE MARKETS
 
The outstanding usability of LB-52U in the melt- through root-pass welding of pipe joints has satis- fied users around the world. LB-52U has been pop- ular for a variety of piping jobs across Russia, Asia and the pacific region. Particularly in Russia, LB- 52U, with its extraordinary reliability, has made a great contribution to the construction of long, oil and gas pipelines in freezing weather. Since 1982, more than 33,000 metric tons of LB-52U  have been consumed in the construction of the Russian pipelines (Figure 2).
 
 
 
 
Figure 2: A pipeline-welding site in Russia where LB-52U is used for joining the girth joints in freezing weather.
 
 
 
 
 
 
 
 
 
 
$:6 $5.1 (7018
 
 
LB-52-18 is a low-hydrogen electrode with a high deposition rate for mild steel and 490 MPa high tensile steel. It is an excellent choice for a variety of applications.
 
Inception of LB-52-18
 
LB-52-18 was developed around 1962. “L” stands for low hydrogen, while “B” symbolizes a slag- shielding covered electrode. “52” refers to the typ- ical tensile strength of deposited metal at the time the electrode was developed. “1” shows that it can be used in all positions, while “8” is the designa- tion for “iron powder, low hydrogen” as in the AWS E7018 specification.
 
High deposition rate
 
The deposition rate is the weight of metal depos- ited per unit of time. Typical deposition rates of LB-52-18 and an ordinary E7016 electrode, as a function of welding current, are shown in Figure 1. Clearly the deposition rates are dependent on welding current, and LB-52-18 provides approxi- mately 20% higher deposition rates when com- pared with the conventional E7016 electrode.
 
 
32
 
30 /%-52-18
 
28
 
26
 
24
 
22
 
20 (7016
 
18
 
16
 
14
120  130  140  150  160  170  180  190  200
:HOGLQJ FXUUHQW ($PS.)
 
essarily results in a faster welding speed or shorter time for welding a certain mass of groove. Shorter welding time can reduce labor costs. LB-52-18, therefore, can provide savings by up to 20% over ordinary E7016 electrodes when the costs for material and overhead are kept constant.
 
Outstanding features
 
The features that help LB-52-18 stand apart from ordinary E7018 electrodes are:
(1) Superior  welding  performance  with  either DCEP or AC currents
(2) Superior mechanical properties with consistent tensile strength and high impact  toughness (Table 1)
(3) Superior crack resistibility
 
 
Table 1: Typical chemical and mechanical properties of LB- 52-18 weld metal tested per AWS A5.1
 
C%
0.07 Si%
0.59 Mn%
0.97 P%
0.013 S%
0.007
0.2% OS (MPa) TS (MPa) El (%) IV (J) PWHT
(°C x h)
500 560 31 –29°C: 110 As weld
420 520 32 –29°C: 140 620x1
 
 
Highly reputed for 45 years
 
Since it was launched, LB-52-18 has seen its fea- tures refined and its markets expanded. Kobe Steel pursues keen quality control in order to maintain the excellency of LB-52-18 produced in Japan and overseas. The maintenance of quality is an impor- tant factor in the high reputation LB-52-18 has per- sistently earned in such diverse fields as machinery, steel structures, bridge construction and shipbuilding.
 
 
Figure 1: A comparison between LB-52-18 and conventional E7016 electrode in terms of deposition rate.
 
 
The  deposition  rate  is  an  important  variable  in welding economics. A higher deposition rate nec-
 
 
The high deposition rate with LB-52-18 is variable for the maintenance welding of heavy-duty machinery in crushing plants.
 
 
 
 
 
$:6 $5.1 (7016
 
 
The No.1 low-hydrogen type electrode for both mild steel and 490 MPa high tensile strength steel suited for almost limitless applications.
 
Inception of LB-52
 
LB-52 was developed around 1958. “L” stands for low hydrogen, while “B” symbolizes a slag-shield- ing covered electrode. “52” refers to the level of approximate tensile strength of the deposited metal when it was developed.
 
Outstanding features
 
The outstanding features of LB-52 among other E7016 electrodes are:
(1) Excellent usability in out-of-position welding with better arc concentration, easier slag removal and smoother bead appearance
(2) Excellent  mechanical  properties  with  consis-
tent tensile strength and high impact toughness
(3) Excellent X-ray soundness
 
 
260
240
 
tion curves of LB-52 weld metals tested with 2mm-V-notch specimens at a wide range of tem- peratures. Due to high impact toughness in both as- welded and postweld heat treated conditions, LB- 52 is used for low-temperature applications down to –20°C, in addition to room temperature and ele- vated temperature applications. Table 1 shows the typical chemical and mechanical properties of LB-
52 weld metal tested in accordance with AWS A5.1.
 
 
Table 1: Typical chemical and mechanical properties of LB-52 weld metal tested in accordance with AWS A5.1
 
C%
0.08 Si%
0.60 Mn%
0.94 P%
0.011 S%
0.006
0.2% OS (MPa) TS (MPa) El (%) IV (J) PWHT
(°C x h)
500 570 32 –29°C:120 As weld
420 520 33 –29°C:150 620 x 1
 
 
Highly reputed for 50 years
 
Since it was launched, LB-52 has seen its features refined and its markets expanded. Kobe Steel pur- sues keen quality control in order to maintain the outstanding features of LB-52 produced in Japan and overseas. The maintenance of quality is an important factor in persistently earning a high rep- utation for LB-52 in almost limitless applications in such various fields as pressure vessels, storage tanks,  pipelines,  machinery,  offshore  structures,
 
220
200
180
160
140
120
100
80
60
40
20
0
 
625ƒ& [ 1K 65
 
 
 
 
 
$V-ZHOG
 
ships, bridges, and steel structures. Kobe Steel is sure LB-52 will be a reliable electrode for your
workshops.
 
í60 í40 í20 0 ·20
7HVW WHPSHUDWXUH (ƒ&)
 
 
 
Figure 1: Charpy impact energy transition curves of LB-52 weld metals in the as-welded and postweld heat treated conti- tions.
 
LB-52 shines in such applications as structures, pipes and vessels in the construction of chemical plants and oil refiner- ies.
 
 
 
 
 
 
 
 
 
 
$:6 $5.1 (6019
 
 
B-14 is a versatile ilmenite type covered electrode for mild steel, offering unsurpassed usability and weldability in all-position butt and fillet welding and in welding sheet metals and medium-thick (up to 20 mm) plates.
 
 
 
A history of ilmenite type electrodes
 
Kobe Steel developed, in 1942, an epoch-making ilmenite type covered electrode: “B-17,” which used ilmenite (a composition of iron oxide and tita- nium oxide) as the raw material for the major part of the coating flux. After a period of years, Kobe Steel developed other ilmenite type covered elec- trodes, B-10 and B-14, so as to satisfy the require- ments of a variety of users.
 
The consumption of ilmenite type covered elec- trodes increased sharply, particularly in the ship- building industry (Figure 1) as the construction of ships increased through the 1960s and 1970s. The annual production of ilmenite type covered elec- trodes in Japan increased year by year up to 132,000 MT in 1973, comprising a major portion of the market for mild steel covered electrodes.
 
 
 
 
 
Figure 1: Ilmenite type electrodes shined in shipbuilding throughout the 1960s and 1970s due to excellent usability and weldability.
 
However, starting in 1975, right after the first glo- bal oil crisis, ship construction began to dry up, after which the consumption of covered electrodes, including the ilmenite type, rapidly decreased. Since then this trend has accelerated, with covered electrodes being superseded by gas metal arc weld- ing wires in order to save welding costs.
 
But the consumption ratio of ilmenite type covered electrodes was kept high until recent years. In 1995, the annual production of ilmenite type cov- ered electrodes was approximately 17,000 MT, which was approximately 30% of all 56,000 MT of mild steel covered electrode produced in Japan.
 
Ilmenite type covered electrodes classified as D4301 in the JIS standard have been also classified as E6019 (iron oxide, titania potassium type) in the AWS standard since 1991. This standardization per AWS is due to Kobe Steel’s active work in the Japan Welding Engineering Society and the Amer- ican Welding Society.
 
Nowadays, ilmenite type covered electrodes are used for welding general steel structures, pipes, and ships in Japan and overseas. Among these ilmenite type covered electrodes B-14 is one of the leading brands, which is produced by Kobe Steel and overseas subsidiary companies: TKW in Thai- land, KWS in Singapore, and INTIWI in Indone- sia.
 
 
 
What characteristics highlight B-14
 
Compared with conventional E6013 electrodes, B- 14 features the following characteristics.
 
(1) Suitable for welding heavy-duty structures due to superior X-ray soundness, higher ductility, higher notch toughness (Figure 2), deeper pen- etration (Figure 3), and consistent tensile prop- erties (Table 1).
 
(2) Suitable for welding thicker steel plates with a thickness of up to about 20 mm due to superior hot crack resistance.
 
(3) Higher welding efficiency due to longer unit electrode length and higher proper currents (Table 2).
 
 
 
 
 
 
120
 
100
 
80
 
60
 
40
 
20
 
 
 
B-14
 
 
 
 
 
 
 
 
E6013
 
Table 1: Typical mechanical properties of B-14 weld metal tested in accordance with AWS A5.1
C% Si% Mn% P% S% 0.10 0.10 0.43 0.015 0.007
YP (MPa) TS (MPa) El (%) IV (J) 410 460 32 –18°C: 82
Table 2: A comparison between B-14 and E6013 covered electrodes on unit length and proper welding current ranges
 
0 -40 -20 0 +20
Testing temperature (℃)
 
Figure 2: Charpy impact test results of B-14 and conventional E6013 weld metals.
 
 
 
 
 
 
 
 
Figure 3: A comparison between B-14 and E6013 covered electrodes (4.0 mmØ,175 A) in fillet weld penetration; P1, P2, and P3 show sizes of penetration.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Tips for better weld results with B-14
 
The electrode’s performance depends greatly on how it is used. In order to get the better welding results, the following key points should be noted.
 
(1) Use B-14 with welding currents within the proper ranges, because excessive welding cur- rents may degrade X-ray soundness, increase spatter, and cause undercut and irregular bead appearance.
 
(2) Redry B-14 at 70-100°C for 30-60 minutes, if the  electrode picked up excessive moisture. This is because excessive moisture in the coat- ing may   degrade electrode’s usability and cause the occurrence of pits in the weld metal.
 
(3) Avoid excessively high temperatures and long time in redrying B-14, because the excessive redrying may damage the coating, causing less penetration, poor X-ray soundness, and elec- trode burn.
 
(4) Because B-14 is a non-low-hydrogen type elec- trode, medium to thick mild steel work should be  preheated at an appropriated temperature and kept during welding at a proper interpass temperature.
 
 
 
 
 
 
 
 
 
 
$:6 $5.18 (5706-*
 
 
TG-S50 is a versatile TIG welding solid wire with excellent usability and mechanical properties used for mild steel, 490 MPa high tensile strength steel and low-temperature Al-killed steel. Users will also find the mechanical properties approved by the ship classification societies to be reliable.
 
Basic characteristics
 
treatment) conditions. TG-S50 weld metal fea- tures high tensile strengths even after long- hour PWHT as shown in Figure 2. This is why TG-S50 is suitable for multi-pass welding of pressure components with thick sections by using a mechanized welding process.
 
 
 
 
 
600
 
 
550
 
 
500
 
 
 
TG-S50 is a solid wire designed specifically for TIG welding. It is classified as AWS A5.18 ER70S-G. As seen in the classification the mini- mum tensile strength of the deposited metal is 70 kilo-pound per square inch or 480 MPa. TG-S50 uses the DCEN (DC Electrode Negative) polarity
 
 
450
 
 
 
 
 
As Weld 625℃x1hr 625℃x4hr    625℃x8hr
Postweld heat treatment
 
and pure argon gas for shielding.
 
Excellent qualities
 
(1) TG-S50 offers less slag generation and better fusion in the root pass welding of pipes in all positions, providing very smooth penetration beads with regular weld ripples. This usability is advantageous in the welding of process pipes (Figure 1) where stricter X-ray soundness is required.
 
Figure 2: Typical tensile strength of TG-S50 weld metal as a
function of PWHT conditions.
 
(3) TG-S50 provides a quite high level of absorbed energy in Charpy impact tests over a range of testing temperatures as shown in Figure 3. This is why TG-S50 is also used for low-tempera- ture applications at down to –40°C.
 
 
 
250
 
 
 
200
 
 
150
 
 
100
 
 
50
 
$V-ZHOG
 
 
 
 
 
 
 
625ƒ& î 5K
3:+7
 
 
 
 
 
 
Figure 1: TG-S50 is very advantageous in the root pass weld- ing of the process piping in all positions due to unsurpassed usability.
 
(2)  TG-S50  offers  consistent  tensile  strength  in both  as-welded  and  PWHT  (postweld  heat
 
0
í60   í50   í40   í30   í20   í10 0 10 20
7HVWLQJ WHPSHUDWXUH (ƒ&)
 
 
Figure 3: Charpy impact test results of TG-S50 weld metal in as-welded and PWHT conditions.
 
 
 
 
 
$:6 $5.18 (5706-6
 
 
TG-S51T resembles TG-S50 in terms of applications of mild steel, 490 MPa high tensile strength steel, and Al-killed steel for low temperature services but is superior in tensile strength under extended postweld heat treatment conditions.
 
Fundamental properties
 
TG-S51T is classified as ER70S-6 in accordance with AWS A5.18 (Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Weld- ing). The typical chemical composition of the wire and the typical mechanical properties of the weld metal are shown in Table 1 with the AWS require- ments.
 
In addition, the pipe-to-nozzle joints on a thick, large pressure vessel may be welded by a mecha- nized GTAW for better quality and efficiency. In these cases, the PWHT may have to be conducted for long hours according to the thickness of the work: e.g. 4 hours for 100-mm thick work. When the work is too big to conduct PWHT at one time in a particular furnace, the PWHT should necessar- ily be conducted several times — thus the total PWHT hours for some weld joints may be 8 to 16 depending on the number of PWHT times. This is why the GTAW weld metal may also be required to satisfy the mechanical properties after long-hour PWHT.
 
Table 2 shows the typical mechanical properties of TG-S51T weld metal after long-hour PWHT. Fig- ure 1 illustrates the effects of PWHT temper parameter on 0.2% offset strength and tensile strength. Clearly, TG-S51T weld metal can satisfy 490 MPa under an extended PWHT condition.
 
 
 
Table 1 Typical chemical and mechanical properties of TG- S51T in comparison with the AWS requirements*1
 
Table 2: Typical mechanical properties of TG-S51T weld metal after long-hour PWHT
 
 
PWHT (°C × h) 0.2% OS (MPa) TS (MPa) El (%) IV (J) at –30°C
625 × 8 440 560 34 170
625 × 24 420 550 35 160
 
 
 
 
 
650
 
600
 
 
 
7HQVLOH VWUHQJWK
 
 
550
 
 
1. Chemical compositions are for solid wire, and mechanical proper- ties are for weld metal in the as-welded condition. Other chemical elements are specified — Ni, Cr, Mo: 0.15% max. each; V: 0.03% max. Cu% includes that of Cu-coating.
 
500
 
450
 
 
0.2% RIIVHW VWUHQJWK
 
 
 
 
Suitable for extended PWHT applications
 
The gas tungsten arc welding (GTAW) process may partly be used (e.g. for root pass welding) on thick-wall work such as pressure vessels and pro- cess pipes that are subject to postweld heat treat-
 
400
 
350
 
300
$V ZHOG
 
 
 
 
 
 
 
18 19 20
3   7 (20 + ORJ W) î 10í3
 
ment (PWHT), although the major part of the welding joints in such equipment are welded gen- erally by more efficient processes such as shielded metal arc welding (SMAW), submerged arc weld-
 
Figure 1: Tensile strength and 0.2% offset strength of TG- S51T weld metal as a function of temper parameter (T: PWHT temperature by Kelvin; t: PWHT hours).
 
 
 
 
 
 
$:6 $5.18 (5706-2
 
 
The NO65G filler wire is the best choice when the AWS ER70S-2 classification is a must for your weld- ing procedures for the root pass welding of pipe joints in particular.
 
Basic characteristics
 
NO65G is a TIG welding solid wire suitable for mild steel and 490 MPa high tensile strength steel. The classification, ER70S-2, contains the follow- ing useful information. The number 70 indicates the required minimum tensile strength as a multi- ple of 1000 psi (70,000 psi = 480 MPa) of the weld metal made using the wire in accordance with the welding conditions specified in AWS A5.18. The letter S designates a solid wire. The suffix 2 indi- cates the chemical composition of the wire.
 
(1) Use proper welding currents for each diameter of the wire: 60-90A for 1.6 mmØ, 80-110A for
2.0 mmØ, and 100-130A for 2.4 mmØ.
 
(2) Use proper flow rates of pure argon gas for torch shielding: 8-15 liter/min. when there is no apparent ambient wind. No back shielding is needed in root pass welding with the pene- tration beads, unless otherwise specified.
 
(3) Remove such dirt attached on the surfaces of the  groove as mill scale, rust, oil and grease, because it can cause  porosity  in  the  weld metal.
 
(4) Control the weld penetration in the root of the groove by controlling the arc exposure spot or the torch placement and the torch oscillation width as shown in Figure 1.
 
 
A: Exce ssive B: P ro pe r C: Inade quate
 
 
 
As shown in Table 1, NO65G contains small amounts of such deoxidizers as Al (aluminum), Ti (titanium) and Zr (zirconium) in addition to the common elements of C (carbon), Si (silicon) and
Mn (manganese). Due to the added deoxidizers,
 
 
 
 
A: To o much forw a rd
 
 
 
 
B: P ro pe r C: Too much ba ckw a rd
 
 
A: Too
 
NO65G can be more resistant against the rust formed on the surfaces of the welding groove. The rust should be removed as much as possible before welding to get better results.
 
A: Too
na rrow
 
B: Prope r
 
w ide
 
 
 
Table  1:  Typical  chemical  and  mechanical  properties  of NO65G tested in accordance with AWS A5.18*1
 
C% Si% Mn% P% S% Cu% Al% Ti% Zr% 0.04 0.54 1.25    0.007   0.014    0.25 0.07 0.08 0.04
 
 
Figure 1: Penetration (top) relates to the torch placement (middle) and the torch oscillation width (bottom), respectively.
 
(5) The weld crater should be terminated on the groove face to prevent the occurrence of a cra- ter crack (Figure 2).
 
 
 
 
 
 
520 600 30 –29°C: 160 625 × 8
 
Root pass welding direction
 
 
1. Chemical compositions are for solid wire, and mechanical proper- ties are for weld metal. Copper includes that of Cu-coating. Electric polarity is DCEN. Shielding gas is pure Ar gas.
 
 
Turn the crater onto the groove face to terminate
 
Figure 2: Proper crater treatment to prevent a crater crack.
 
 
 
shown in Table 2. Figure 1 shows typical Charpy impact test results of the multi-pass weld metals.
 
 
 
 
$:6 $5.17 )7$6-(+14, )736-(+14
 
 
MF-38/US-36 is a versatile filler metal combination of fused flux and solid wire for submerged arc weld- ing (SAW) of butt and fillet joints in ships, industrial machinery, vessels, steel frames, and bridges.
 
Table 2: Approvals of ship classification societies*1
 
AB LR NV BV NK Others
2T,2YT
3M,3YM 2T,2YT
3YM Ⅱ YT ( Ⅲ YM) A2,2YT A3,3YM KAW52T KAW53M GL,CR KR
1. AB: American Bureau of Shipping; LR: Lloyd's Register of Ship- ping; NV: Det Norske Veritas; BV: Bureau Veritas; NK: Nippon Kaiji Kyokai; GL: Germanischer Lloyd; CR: Central Research of Ships S.A.; KR: Korean Register of Shipping.
 
 
 
Basic properties
 
MF-38 is a fused type flux classified as F7A6- EH14 and F7P6-EH14 when combined with US- 36 solid wire classified as EH-14 in accordance with AWS A5.17 (Specification for Carbon Steel Electrodes and Fluxes for Submerged Arc Weld- ing). According to the classification system each designator is given for the particular information as follows: “F” for virgin flux, “7” for the mini- mum tensile strength of weld metal (70,000 psi or 480 MPa), “A” for as-welded condition, “P” for postweld heat treated condition, “6” for the Charpy impact testing temperature of –60°F (–51°C), “E” for electrode, “H” for high manganese content, and “14” for the nominal carbon content of wire (0.14%). Table 1 shows the typical chemical and
 
 
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70
 
 
 
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30
 
 
 
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mechanical properties of MF-38/US-36 tested as per AWS A5.17.
 
 
Table 1: Typical chemical and mechanical properties of MF- 38/US-36 tested in accordance with AWS A5.17*1
 
 
Wire C% Si% Mn% P% S% Cu%
0.12 0.03 1.95 0.013 0.005 0.11
 
Weld metal C% Si% Mn% P% S% Cu%
0.09 0.32 1.63 0.018 0.011 -
0.2% OS (MPa) TS (MPa) El (%) IV (J) PWHT (°C × h)
490 570 30 –51°C: 59 As weld
420 530 31 –51°C: 64 620 × 1
1. Welding current: AC
 
 
Outstanding features
 
MF-38/US-36 is more resistible to the rust and dirt of the base metal and thus offers excellent porosity resistance and X-ray soundness. The mechanical properties of multiple pass welds are consistent with approvals of ship classification societies as
 
Figure 1: Consistent results in Charpy impact testing of MF- 38/US-36 multi-pass weld metal (Welding current: AC).
 
Tips for successful welding results
 
(1) MF-38 has varieties of flux mesh sizes: 12×65, 20×200, and 20×D. The proper flux size should be selected according to welding current to be used for better usability. In general, coarse par- ticle flux uses lower currents and fine particle flux is suitable for higher currents: 12×65 for 600A max., 20×200 for 600-1000A, and 20×D
for 800A or higher. The most appropriate size of US-36 should be selected from among 1.6, 2.0, 2.4, 3.2, 4.0, 4.8, and 6.4mm according to the thickness of the work and welding current to be used.
(2) MF-38 is a fused flux with glassy appearance and thus is more resistible to moisture pick up. However, the flux should be redried before use by 150-350°C for 60 minutes to remove depos- ited moisture on the surfaces of the flux parti- cles, thereby preventing welding defects.
 
 
 
 
 
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