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Submerged arc welding process for low-temperature high-toughness niobium micro-alloy steel and welding wire thereof

A technology of micro-alloy steel and submerged arc welding, which is applied in the direction of welding medium, welding equipment, welding equipment, etc., can solve the problems of low-temperature toughness decrease of welded joints, difficult control of welding quality, and too far difference in toughness index, etc., and achieve fast welding speed , high safety margin, excellent low temperature impact and crack resistance

Inactive Publication Date: 2010-06-09
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the welding of high-toughness low-temperature steel has high requirements on welding materials, welding processes, especially heat input, and the welding quality is not easy to control
The low-temperature toughness of welded joints is significantly reduced, and the impact energy of the deposited metal and heat-affected zone is far from that of the base material.
In submerged arc welding with multiple layers and large heat input, the performance degradation of this joint is more significant, which cannot meet the requirements of the current automated manufacturing industry

Method used

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  • Submerged arc welding process for low-temperature high-toughness niobium micro-alloy steel and welding wire thereof
  • Submerged arc welding process for low-temperature high-toughness niobium micro-alloy steel and welding wire thereof
  • Submerged arc welding process for low-temperature high-toughness niobium micro-alloy steel and welding wire thereof

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Experimental program
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Effect test

Embodiment 1

[0035] Substrate: Low-temperature high-toughness niobium microalloy steel plate produced by thermomechanical controlled rolling process (TMCP) + normalizing, the thickness combination is 30mm+30mm; the mechanical properties of the steel plate are: yield strength R p0.2 : 380MPa, tensile strength R m : 490MPa, Elongation A: 33%, -70℃CA KV Impact energy: 181J. The size of the test plate is 600mm×400mm×12mm; the submerged arc welding groove adopts X-shaped symmetrical groove, the groove angle is 60°, and the blunt edge is 6mm.

[0036] The results of welding heat simulation are shown in the table below:

[0037] Table 1

[0038] Line energy / (kJ / cm)

10

20

30

40

50

A KV (-70℃) / (J)

345 370

410 427

423 301

102 98

27 18

[0039] From the above thermal simulation results, it can be seen that the welding input energy is not more than 30kJ / cm, and the sample has high impact toughness. Select the following w...

Embodiment 2

[0044]Substrate: Low-temperature high-toughness niobium microalloy steel plate produced by thermomechanical controlled rolling process (TMCP) + normalizing, the thickness combination is 52mm+52mm; the mechanical properties of the steel plate are: yield strength R p0.2 : 370MPa, tensile strength R m : 480Pa, Elongation A: 32%, -70℃CA KV Impact energy: 192J. The size of the test plate is 600mm×400mm×30mm; the submerged arc welding groove adopts X-shaped symmetrical groove, the groove angle is 60°, and the blunt edge is 6mm.

[0045] The results of welding heat simulation are shown in the table below:

[0046] Table 2

[0047] Line energy / (kJ / cm)

10

20

30

40

50

A KV (-70℃) / (J)

327 351

370 384

208 231

87 78

30 28

[0048] From the above thermal simulation results, it can be seen that the welding input energy is not more than 30kJ / cm, and the sample has high impact toughness. Select the following weldin...

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Abstract

The invention relates to a welding process and a welding wire thereof, in particular to a submerged arc welding process for low-temperature high-toughness niobium micro-alloy steel and a welding wire thereof. The process comprises the following steps of: performing a welding heat simulation experiment on steel plates to determine the welding line energy range which can be adopted during the welding; adopting an X-shaped symmetrical groove as a submerged arc welding groove, wherein the angle of the groove is 60 degrees, and the length of a truncated edge is 6mm; adopting a welding wire with the tensile strength of between 540 and 620MPa and the impact work Akv of between 120 and 170J; ensuring that the welding current is between 500 and 580A, the welding voltage is between 31 and 35V, the welding speed is between 30 and 45cm / min, and the baking rule of a welding flux is 350 DEG C*1h; and ensuring that the submerged arc welding adopts multi-layer multi-channel continuous welding and the inter-layer temperature is controlled to between 100 and 150 DEG C, and immediately performing stress relief treatment at the temperature of 580 DGE C after the welding. The method has excellent welding processing properties, and can ensure that the mechanical property of a welding joint of the low-temperature high-toughness niobium micro-alloy steel meets design requirement and particularly various positions of the joint maintain higher low-temperature impact toughness.

Description

technical field [0001] The invention relates to a welding process and its welding wire, in particular to a submerged arc welding process of low-temperature high-toughness niobium microalloy steel and its welding wire. Background technique [0002] With the rapid development of my country's petrochemical industry, large-scale ethylene, synthetic ammonia, and urban coal pressurized vaporization projects have developed rapidly. Gas liquefaction, separation, and production, storage, and application of liquefied gases have become quite common. The development of low-temperature technology and equipment Development has promoted the development of low temperature pressure vessel steel, and the demand for low temperature steel at -60°C or -70°C is becoming increasingly urgent. [0003] In order to meet the needs of various low-temperature pressure vessel storage tanks, NISCO has developed a high-toughness low-temperature vessel steel, whose comprehensive mechanical properties are sup...

Claims

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Application Information

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IPC IPC(8): B23K9/18B23K9/235B23K9/095B23K33/00B23K35/30
Inventor 何烈云龚云芳何宜柱楚觉非方俊飞
Owner NANJING IRON & STEEL CO LTD
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