Covered Electrode For Low-Alloy Steel

LOW ALLOY STEEL—STICK ELECTRODE

 

1.SELECTION RECOMMENDATION::


Material of Base metal, tensile strength, assembly structure, and method of welding are important for selecting welding consumable. For example, ASTM A387 G.11 contains 1.25%Cr + 0.5%Mo. Its  tensile strength range from 515 to 690 N/mm2, so the suitable consumable are E8018-B2, E8018-B2, or ER80S-B.

 

 

According to AWS A5.5, the classification and features of stick electrodes are as below:

Classification

Characteristic

Group

Features

Carbon molybdenum steel

Heat resistant

A1

1.The heat resistance and anti-corrosion abilities increase because of adding 0.5%Mo, however the impact toughness decreases.


2.Suitable for the welding for steel plates of ASTM A204 or pipes of A355 P1. 

Chrome molybdenum steel

Heat resistant

B2B3B4B5B6B7B8

1.The heat resistance and anti-corrosion abilities increase because of adding 0.5%~10%Cr - 0.5%~1.25%Mo, however the impact toughness decreases.


2.Suitable for the welding for steel plates of ASTM A387 or pipes of A213 or A335.

Heat resistant

B23

1.Under high temperature, the creep and anti-fatigue, impact toughness, and Anti-oxidation and corrosion abilities increase because of adding 2.5% Cr–1.5% W–0.2%Mo–0.20% V–0.04% Nb.


2.Suitable for the welding for ASTM A283.

Heat resistant

B24

1.Under high temperature, the creep and anti-fatigue, impact toughness, and Anti-oxidation and corrosion abilities increase because of adding 2.5% Cr–1.0% Mo–0.20%V–0.10% Ti–0.04% Nb.


2.Suitable for the welding ASTM A283.

Heat resistant

B91

1.Under high temperature, the creep and anti-fatigue, impact toughness, and Anti-oxidation and corrosion abilities increase because of adding 9% Cr–1% Mo and minor Nb&V.


2. Suitable for the welding for steel plates of ASTM A387 Gr.91 or A213 T91, or pipes of A335 P91.


3.The heat input, temperature, and post heat treatment must be strictly followed.  

Heat resistant

B92

1.Under high temperature, with excellent creep and anti-fatigue, impact toughness, and Anti-oxidation and corrosion abilities because of adding 9% Cr–2% W–0.5% Mo–0.20%V–0.05% Nb.


2.Suitable for the welding for pipes of ASTM A213 T92 or A335 P92.


3.The heat input, temperature, and post heat treatment must be strictly followed.

Nickel steel

Low Temperature

C1C2C3C4C5

1.The material is with 1~6.5%Ni , and classified to 5 grades. With excellent impact toughness when the temperature ranges –115℃~room temperature.


2.Suitable for the welding for steel plates of ASTM ASTM A203 Gr.91 or A645.

Nickel molybdenum steel

Special purpose

NM1

1.The material, with 1%Ni - 0.5%Mo and minor V&Cu, is for high tensile strength under special circumstance.


2.Not require post heat treatment.

Special purpose

NM2

1.The material, with 2%Ni - 0.4%Mo, is for high tensile strength under special circumstance.


2.For the equipment of Nuclear power plant because of longer time of post heat treatment. To remain the strength, there is usually falling weight test.

Manganese Molybdenum Steel

Special purpose

D1D2D3

1.The material, with 1.5~1.8%Mn - 0.3~0.5%Mo – 0.2~0.4%Ni , has better performance of tensile strength and impact toughness than Carbon molybdenum steel and Nickel molybdenum steel.


2.PWHT is required. 

Regular

Muti-classification

G

1.Classified to 6 materials and range E70~E120 by tensile strength. 


2. The requirement for the chemical composition of G series is that, P&S need to be under its upper limit, and at least one of the others need to be above its lower limit. 


3. The requirement for the chemical composition of G series is that, P&S need to be under its upper limit, and at least one of the others need to be above its lower limit. 

Military

Military

M

1.For Military, with multi-alloy, especially Ni, to meet the requirement of low temperature impact toughness. 


2.Diffusible hydrogen is required, and heat input need to be strictly controlled, but post heat treatment is not required.


Pipe

Cellulose

P1

1.Designed for first bead of pipe’s vertical welding, and normally with V-down position. 


2.Used for the welding of pipes of API–5L-X52,API–5L-X65,API–5L-X70.

Low hydrogen

P2

1.Designed for pipe welding, and suitable for the layer after first bead. With all positions and V-down.


2.Designed for API–5L series, up to X80 grade pipe. 

Atmospheric Corrosion  Resistant

Anti-pitting corrosion

W1W2

1.With minor Ni, Cr, and 0.5%Cu, to improve Anti-pitting corrosion.


2.Designed for the welding of Atmospheric Corrosion Resistant steel (e.g ASTM A242 or A588)

 

 

 

2.Welding Operation:


(1)Storage


①The cover of low alloy steel is normally low hydrogen, which need to avoid the environment of high humidity (≧80%R.H) and high temperature(≧30℃), to avoid humid cover of electrode.

 

②Re-bake low tungsten electrode need to be put in the oven or containers with temperature 100~150℃. Taking proper quantity to reduce the humidity and avoid high diffusible hydrogen. See annex for drying condition.

 

(2)Note


①The temperature of heat input, preheat, bead temperature, post heat, and post heat treatment must be strictly controlled, to avoid crack or quality problem. 

 

Oxide layer, water, oil, rust, and anything on surface will increase gas and diffusible hydrogen, and case the defects, so the surface must be clean before welding.

 

Low hydrogen electrode need to be welded with short arc to avoid water and nitrogen into the beads and causing air hole or crack.

 

Low hydrogen electrode need to take the method of forward-back welding for arcing. The arcing point should be 1~2cm in front of welding start point, to eliminate air holes. 

 

The current is suggested as low as possible, and the width of weave is also suggested as small as possible, to avoid the alloy damaged by burning, and the grain enlarge. 

 

⑥When B3(2.25%Cr-1%Mo) Heat resistant steel is heated under the temperature 400-500℃ for long period of time, the trace elements(P、Sb、As、Sn) in the bead will spread to the cell of Austenitic, and cause the strength of cell reduce and the toughness degrade. This is so called temper brittleness. To avoid this, the composition need to be managed, and the temperature of bead need to be controlled in 160~190℃.

 

View:

SN-88G

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8018-G
JIS Z3211 E5518-G
EN ISO 2560-A E 50 5 2Ni B 3 2
GB T5118 E5518-G

SN-86G

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8016-G
JIS Z3211 E5516-G
EN ISO 2560-A E 50 5 2Ni B 1 2
GB T5118 E5516-G

SN-86C3

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8016-C3
JIS Z3211 E5516-N2
EN ISO 2560-A E 46 4 1Ni B 1 2
GB T5118 E5516-C3

SN-86C2

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8016-C2
JIS Z3211 E5516-N7
EN ISO 2560-A E 46 6 3Ni B 1 2
GB T5118 E5516-C2

SN-86C1

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8016-C1
JIS Z3211 E5516-N5
EN ISO 2560-A E 46 6 2Ni B 1 2
GB T5118 E5516-C1

SR-592

低合金耐熱鋼SMAW銲接
AWS A5.5 E9015-B92
JIS --
EN --
GB --

SR-591

低合金耐熱鋼SMAW銲接
AWS A5.5 E9015-B91
JIS --
EN --
GB --

SR-96B3

低合金耐熱鋼SMAW銲接
AWS A5.5 E9016-B3
JIS Z3223 E6216-2C1M
EN ISO 3580-A E CrMo2 B 1 2
GB T5118 E6016-B3

SR-86B6

低合金耐熱鋼SMAW銲接
AWS A5.5 E8016-B6
JIS Z3223 E5516-5CM
EN ISO 3580-A E CrMo5 B 1 2
GB --

SR-78A1

低合金耐熱鋼SMAW銲接
AWS A5.5 E7018-A1
JIS Z3223 E4918-1M3
EN ISO 3580-A E Mo B 3 2
GB T5118 E5018-A1

SR-86B8

低合金耐熱鋼SMAW銲接
AWS A5.5 E8016-B8
JIS Z3223 E5516-9C1M
EN ISO 3580-A E CrMo9 B 1 2
GB --

SR-96B9

低合金耐熱鋼SMAW銲接
AWS A5.5 E9016-B91
JIS --
EN --
GB --

SR-76A1

低合金耐熱鋼SMAW銲接
AWS A5.5 E7016-A1
JIS Z3223 E4916-1M3
EN ISO 3580-A E Mo B 1 2
GB T5118 E5016-A1

SC-70A1

低合金耐熱鋼SMAW銲接
AWS A5.5 E7010-A1
JIS Z3223 E4910-1M3
EN ISO 3580-A E Mo B 2 2
GB T5118 E5010-A1

SL-120

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E12016-G
JIS Z3211 E8316-G
EN ISO 18275-A E 79 2 Mn2NiCrMo B 1 2
GB T5118 E8516-G

SL-110

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E11016-G
JIS Z3211 E7616-G
EN ISO 18275-A E 69 2 Mn2NiMo B 1 2
GB T5118 E7516-G

SL-108M

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E10018-M
JIS Z3211 E6918-N3M2
EN ISO 18275-A E 62 5 1.5NiMo B 3 2
GB T5118 E7018-M

SL-80

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E9016-G
JIS Z3211 E6216-G
EN ISO 18275-A E 55 3 B 1 2
GB T5118 E6016-G

SL-63

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E8013-G
JIS --
EN --
GB --

SW-78W1

低合金耐候性鋼SMAW銲接
AWS A5.5 E7018-W1
JIS Z3214 DA5016-G
EN --
GB T5118 E5018-W

SW-88W2

低合金耐候性鋼SMAW銲接
AWS A5.5 E8018-W2
JIS Z3214 DA5816-W
EN --
GB T5118 E5518-W

SR-88B2

低合金耐熱鋼SMAW銲接
AWS A5.5 E8018-B2
JIS Z3223 E5518-1CM
EN ISO 3580-A E CrMo1 B 3 2
GB T5118 E5518-B2

SR-98B3

低合金耐熱鋼SMAW銲接
AWS A5.5 E9018-B3
JIS Z3223 E6218-2C1M
EN ISO 3580-A E CrMo2 B 3 2
GB T5118 E6018-B3

SN-88C2

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8018-C2
JIS Z3211 E5518-N7
EN ISO 2560-A E 46 6 3Ni B 3 2
GB T5118 E5518-C2

SN-88C3

低合金耐低溫鋼SMAW銲接
AWS A5.5 E8018-C3
JIS Z3211 E5518-N2
EN ISO 2560-A E 46 4 1Ni B 3 2
GB T5118 E5518-C3

SL-118M

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E11018-M
JIS Z3211 E7618-N4M2
EN ISO 18275-A E 69 5 Mn2NiCrMo B 3 2
GB T5118 E7518-M

SN-98G

低合金耐低溫鋼SMAW銲接
AWS A5.5 E9018-G
JIS Z3211 E6218-G
EN ISO 18275-A E55 4 Mn1NiMo B 3 2
GB T5118 E6018-G

SL-60

≧550N/mm2級高張力鋼SMAW銲接
AWS A5.5 E8016-G
JIS Z3211 E5516-G
EN ISO 2560-A E 46 3 B 3 2
GB T5118 E5516-G

SR-86B2

低合金耐熱鋼SMAW銲接
AWS A5.5 E8016-B2
JIS Z3223 E5516-1CM
EN ISO 3580-A E CrMo1 B 1 2
GB T5118 E5516-B2