Process for welding duplex stainless steel

A duplex stainless steel, welding process technology, applied in welding equipment, manufacturing tools, arc welding equipment, etc., to achieve the effect of excellent welding effect

Active Publication Date: 2011-02-16
CHINA NAT CHEM ENG NO 7 CONSTR
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] In particular, the welding process of the present invention adopts a specific shielding gas that is beneficial to the welding of duplex stainless steel, and at the same time adjusts the heat input and i...

Method used

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  • Process for welding duplex stainless steel
  • Process for welding duplex stainless steel
  • Process for welding duplex stainless steel

Examples

Experimental program
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Effect test

example 1

[0061] Example 1. Welding of duplex stainless steel SAFUREX and duplex stainless steel SAFUREX

[0062] 1. Adopt single V-shaped butt weld. Groove angle α: 35±2.5°; gap b: 2-4mm; blunt edge p: 0.8-2.5mm, for assembly, welding position is 6G (45°fixed welding).

[0063] 2. Duplex stainless steel is welded without preheating and post-weld heat treatment.

[0064] 3. The bottom welding and the second layer of welding bead are welded by tungsten argon arc welding, and the argon arc welding machine is WS-400IGBT, and the polarity of the power supply is DC positive connection. For the back protection gas, the flow rate is 6-10L / min; for the front side, a mixture of 98% argon + 2% nitrogen is used as the protection gas, and the flow rate is 8-15L / min. The welding wire is Swedish SAFUREXφ2.4 or AWS: ER2209, when the wall thickness is ≤3mm, the line energy is 10-20KJ / cm; when the wall thickness is 3-12mm, the line energy is 20-30KJ / cm; welding by certified welders, And measure the i...

example 2

[0083] Example 2. Welding of duplex stainless steel and carbon steel

[0084] There are two ways: one is to surfacing a transition layer on one side of the carbon steel with a transition electrode E309L before formal welding, and then smooth it and pair it with the duplex stainless steel on the other side for welding. details as follows:

[0085] 1. Adopt single V-shaped butt weld. Groove angle α: 35±2.5°; gap b: 2-4mm; blunt edge p: 0.8-2.5mm. The welding position is 6G (45° fixed welding).

[0086] 2. Duplex stainless steel welding does not require preheating and post-weld heat treatment.

[0087] 3. The bottom welding and the second layer of welding bead are welded by tungsten argon arc welding. The argon arc welding machine is WS-400IGBT, the polarity of the power supply is DC positive connection, and 100% nitrogen or 90% nitrogen + 10% hydrogen ( volume percentage) as the back protection gas, the flow rate is 6-10L / min, and the front side uses a mixture of 98% argon +...

example 3

[0113] Example 3. Welding of duplex stainless steel and 316L

[0114] 1. Adopt single V-shaped butt weld. Groove angle α: 35±2.5°; gap b: 2-4mm; blunt edge p: 0.8-2.5mm, for grouping, welding position is 6G (45°fixed welding).

[0115] 2. Duplex stainless steel welding does not require preheating and post-weld heat treatment.

[0116] 3. The bottom welding and the second layer of welding bead are welded by tungsten argon arc welding. The argon arc welding machine is WS-400IGBT, the polarity of the power supply is DC positive connection, and 100% nitrogen or 90% nitrogen + 10% hydrogen ( volume percentage) as the back protection gas, the flow rate is 6-10L / min, and the front side uses a mixture of 98% argon + 2% nitrogen as the protection gas, the flow rate is 8-15L / min. The welding wire is Swedish φ2.4, ER316L or Sandvik25, 22, 2L Mn welding wire. When the wall thickness is ≤3mm, the line energy is 10-20KJ / cm; when the wall thickness is 3-12mm, the line energy is 20-30KJ / cm;...

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Abstract

The invention relates to a process for welding duplex stainless steel, in particular to the process for welding the duplex stainless steel used for high-sulfur content refining equipment, highly-corrosive petrochemical equipment and pipelines, high-parameter power devices, and the chloridion-corroded environments of seawater and the like. In the process, a specific protective gas favorable for the welding of the duplex stainless steel is adopted, and simultaneously limited linear energy and inter-layer temperature are regulated in the welding process, so that the unfavorable defects of the conventional welding process can be overcome, and a metallographic structure with the ferrite content of 30 to 70 percent and a ferritic phase in percentage equivalent to that of an austenitic phase is obtained. A welding joint obtained by the welding process has high mechanical properties, high strength and hardness, particularly high yield strength which is about twice that of austenitic stainless steel, high thermal fatigue resistance, pitting corrosion resistance, crevice corrosion resistance, intercrystalline corrosion resistance and high weldability.

Description

technical field [0001] The invention relates to a welding process of duplex stainless steel, especially for duplex stainless steel in the environment of high sulfur content refining equipment, highly corrosive petrochemical equipment, pipelines and high-parameter power devices, and chloride ion corrosion environments such as seawater. Welding process for stainless steel. Background technique [0002] Duplex stainless steel is a new type of stainless steel material that has developed rapidly in recent years. It has a variety of models, and there are 25 types of steel listed in the ASME code (American Society of Mechanical Engineers), and its classification number is P10H. Since the microstructure of duplex stainless steel is austenite + ferrite structure , so it has good corrosion resistance. Duplex stainless steel has better resistance to stress corrosion cracking than 316L austenitic stainless steel (hereinafter referred to as 316L), especially in H 2 This is the case in ...

Claims

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Application Information

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IPC IPC(8): B23K9/00B23K9/16
Inventor 孙逊
Owner CHINA NAT CHEM ENG NO 7 CONSTR
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