Gas protection welding method for rack steel with thickness being greater than or equal to 80 mm

A technology of gas shielding and welding method, applied in welding equipment, welding accessories, characteristics of welding rod, etc., can solve the problems of affecting efficiency, many welding passes, etc., to improve welding efficiency, reduce welding passes, high impact toughness reserve and The effect of safety margins

Inactive Publication Date: 2020-09-11
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the use of Φ1.2mm welding wire, there are many welding passes, which affects the efficiency

Method used

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  • Gas protection welding method for rack steel with thickness being greater than or equal to 80 mm

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Experimental program
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Effect test

Embodiment 1

[0031] A gas shielded welding method for rack steel with a thickness ≥ 80mm, the steps of which are:

[0032] 1) Base metal properties: yield strength R eL : 640MPa, tensile strength R m 725MPa, elongation A: 20%, -40 o CKV 2 Impact energy: 100J; A514 steel rack steel thick plate is 114.3mm, test size: 600mm×400mm×114.3mm, for equal thickness butt welding;

[0033] 2) Groove form: double-sided V-shaped and symmetrical, the groove angle is 27° on one side, 12° on the other side, and 1.5mm on the blunt side;

[0034] 3) Welding matching material: gas-shielded welding wire deposited metal tensile strength: 698MPa, mechanical properties of welding wire deposited metal tensile strength R m : 720MPa, elongation A: 31%, reduction of area Z: 66%, -40℃KV 2 Impact energy: 138J; wire diameter: Ф1.6mm;

[0035] Welding process specifications: welding current at 400A, welding voltage at 30V, welding speed at 30cm / min, welding line energy at 24kJ / cm; use argon-rich gas protection, tha...

Embodiment 2

[0042]A gas shielded welding method for rack steel with a thickness ≥ 80mm, the steps of which are:

[0043] 1) Base metal properties: Yield strength ReL: 635MPa, tensile strength Rm: 715MPa, elongation A: 16%, -40oCKV2 impact energy: 110J; A514 steel is rack steel thick plate at 80mm, test size: 600mm×400mm ×80mm, for equal thickness butt welding;

[0044] 2) Groove form: double-sided V-shaped and symmetrical, groove angle, one side is 30°, the other side is 10°, and the blunt side is 1.3mm;

[0045] 3) Welding matching material: gas-shielded welding wire deposited metal tensile strength: 705MPa, mechanical properties of welding wire deposited metal tensile strength Rm: 730Pa, elongation A: 30%, section reduction Z: 68%, -40℃ KV2 impact energy: 120J; wire diameter: Ф1.6mm;

[0046] Welding process specification: welding current at 430A, welding voltage at 31V, welding speed at 34cm / min, welding line energy at 23kJ / cm; using argon-rich gas protection, that is, 80%Ar+20%CO2, ...

Embodiment 3

[0053] A gas shielded welding method for rack steel with a thickness ≥ 80mm, the steps of which are:

[0054] 1) Base metal properties: Yield strength ReL: 640MPa, tensile strength Rm: 745MPa, elongation A: 21%, -40oCKV2 impact energy: 110J; A514 steel is rack steel thick plate at 114.3mm, test size: 600mm× 400mm×114.3mm, for equal thickness butt welding;

[0055] 2) Groove form: double-sided V-shaped and symmetrical, the groove angle is 31° on one side, 11° on the other side, and 1.9mm on the blunt side;

[0056] 3) Welding matching material: gas-shielded welding wire deposited metal tensile strength: 725MPa, mechanical properties of welding wire deposited metal tensile strength Rm: 725MPa, elongation A: 28%, section reduction Z: 66%, -40℃ KV2 impact energy: 132; wire diameter: Ф1.6mm;

[0057] Welding process specifications: welding current at 450A, welding voltage at 31.5V, welding speed at 35cm / min, welding line energy at 24kJ / cm; argon-rich gas protection is used, that ...

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Abstract

A gas protection welding method for rack steel with the thickness being greater than or equal to 80 mm is as follows: the base material performance is greater than or equal to 620 MPa, the Rm is in the range of 690-895 MPa, the extension rate A is greater than or equal to 16%, and -40 DEG CKV2 is greater than or equal to 47 J; butt joint welding is carried out; double-sided V-shape symmetry is conducted; and welding of a matching material is conducted, wherein the ReL of a gas protection welding wire is greater than or equal to 690 MPa, the diameter Phi of the welding wire is 1.6 mm, argon-rich gas protection is adopted, the temperature of preheating before welding is 155-165 DEG C, the interlayer temperature is 150-180 DEG C, and the heat treatment temperature after welding is 405-415 DEGC. According to the method, the -40 DEG C KV2 of a three-zone impact energy weld seam of a joint is 125-135 J; the -40 D EG C KV2 of the fusion line impact energy is 109-127 J, and the -40 DEG C KV2of a heat-affected zone (1 mm) is 128-145 J; a joint overheating area is mainly bainite, the weld seam metal is mainly of an acicular ferrite structure, the three-zone of the joint has high impact toughness reserve and safety margin, and cracks are not generated; and the welding efficiency is improved by at least 25% due to the adoption of the welding wire with the diameter phi of 1.6 mm, and operation is easy.

Description

technical field [0001] The invention relates to a gas shielded welding method, in particular to a method suitable for welding tensile strength R m The gas-shielded welding method of ≥690MPa grade rack steel is specifically used for the gas-shielded welding method of welding rack steel with a thickness of ≥80mm for marine engineering, that is, A514 steel. Background technique [0002] Rack steel A514 is a marine engineering steel smelted by electroslag remelting process. After rolling, the steel is quenched at 940°C + tempered at 680°C×300min. The steel is used in the production of main bearing parts of marine products such as jack-up platform pile legs and platform cranes. This kind of steel tends to be hardened during welding, and a large amount of hard and brittle martensite is easily produced in the heat-affected zone, resulting in severe embrittlement of the welded joint, and in severe cases, the toughness and plasticity of the welded joint will be greatly reduced. ...

Claims

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Application Information

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IPC IPC(8): B23K9/16B23K9/235B23K9/28B23K9/32
CPCB23K9/16B23K9/235B23K9/28B23K9/32
Inventor 牟文广黄治军方要治郑绍鹏刘文艳钟如涛胡因洪何嘉
Owner 武汉钢铁有限公司
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