Unlock instant, AI-driven research and patent intelligence for your innovation.

A self-fluxing welding method for 2507 super duplex stainless steel sheets

A duplex stainless steel and welding method technology, applied in welding equipment, arc welding equipment, manufacturing tools, etc., can solve problems such as weld oxidation, welding speed reduction, concave or convex, etc.

Active Publication Date: 2022-05-20
UNIV OF SCI & TECH BEIJING
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Compared with the prior art, the self-fluxing welding method for 2507 super duplex stainless steel sheets provided by the present invention has a welding speed not greater than 6mm / s, which prevents the molten pool from being separated from the protection of the argon gas of the welding torch without complete cooling due to excessive welding speed. , resulting in weld oxidation; in addition, the welding speed is reduced. For weldments with different plate thicknesses, a current selection formula is proposed. When the current I is (44~47)*h, the heat input can be effectively controlled. In the above current range The heat input within is just within the appropriate heat input range for penetration of the weldment, avoiding deformation caused by incomplete penetration or excessive welding area, and appearance defects such as concave or convex weld seams

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A self-fluxing welding method for 2507 super duplex stainless steel sheets
  • A self-fluxing welding method for 2507 super duplex stainless steel sheets
  • A self-fluxing welding method for 2507 super duplex stainless steel sheets

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The selected steel plates to be welded are two 1.2mm thick 2507 super duplex stainless steel cold-rolled plates, and the steel plate size is 75mm×300mm×1.2mm. Chemical composition of 2507 super duplex stainless steel sheet: C: 0.027% Si: 0.65% Mn: 0.92% P: 0.025% S: 0.001% Cr: 24.83% Ni: 6.95% Mo: 3.99% N: 0.261%, the rest is iron and unavoidable impurities.

[0029] Step 1: Degrease, derust, and remove dirt on the surface of the 1.2mm thick 2507 super duplex stainless steel cold-rolled sheet. One or more of the above treatment methods can be selected based on the actual conditions of the cold-rolled sheet.

[0030] Step 2: Fix the cold-rolled 2507 super duplex stainless steel sheet to be welded with a piano-type fixture, and pair them together to form an I-shaped groove without leaving any gaps.

[0031]Step 3: Welding with a TIG welding machine directly connected to DC, the diameter of the tungsten electrode is 2.4mm; the shielding gas of the welding torch nozzle is...

Embodiment 2

[0033] The material and welding method of this embodiment copper embodiment 1, the only difference is that in step 3, a direct current TIG welding machine is used for welding, and the diameter of the tungsten pole is 2.4mm; the shielding gas of the welding torch nozzle is pure argon, and the flow rate of argon is 9L / min; the back shielding gas is pure nitrogen, and the nitrogen flow rate is 8L / min; no copper welding pad is used, the welding voltage U is 10V, the welding speed v is 5mm / s, and the welding current I is (45~46)*h, Namely 54~55.2A, the value of this embodiment I is 55A, and the welding heat input is 110J / mm at this moment. Welding heat input is the product of current and voltage divided by welding speed.

Embodiment 3

[0045] The selected steel plates to be welded are two 0.9mm thick 2507 super duplex stainless steel cold-rolled plates, and the steel plate size is 75mm×300mm×0.9mm. Chemical composition of 2507 super duplex stainless steel sheet: Chemical composition of 2507 super duplex stainless steel sheet: C: 0.027% Si: 0.65% Mn: 0.92% P: 0.025% S: 0.001% Cr: 24.83% Ni: 6.95% Mo: 3.99% N: 0.261%, the rest is iron and unavoidable impurities.

[0046] Step 1: Degrease, derust, and remove dirt on the surface of the 0.9mm thick 2507 super duplex stainless steel cold-rolled sheet.

[0047] Step 2: Fix the 2507 super duplex stainless steel cold-rolled sheet to be welded with a piano-type fixture, and form an I-shaped groove in a team without leaving any gaps.

[0048] Step 3: Welding with a TIG welding machine with direct current connection, the diameter of the tungsten electrode is 2.8mm; the protective gas of the welding torch nozzle is pure argon, and the flow rate of argon is 10L / min; the ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
diameteraaaaaaaaaa
diameteraaaaaaaaaa
Login to View More

Abstract

An embodiment of the present invention provides a self-fluxing welding method for 2507 super duplex stainless steel sheets, which is aimed at cold-rolled 2507 super duplex stainless steel sheets with a thickness of 0.3-1.5 mm. Using Ar+2~5%N 2 The mixed gas is used as the shielding gas of the welding torch, and the non-filling TIG welding method using pure nitrogen as the shielding gas on the back of the welding can effectively suppress the escape of N from the molten pool during the welding process, and control the welding current to ensure proper welding heat input range, so that the proportion of austenite and ferrite in the weld is kept within a reasonable range, so as to ensure that the corrosion resistance of the welded joint is as close as possible to the base metal. And adopting this current control method makes the weld seam smooth and clean, the weld seam does not produce concave or convex, the deformation of the weldment after welding is small, and the post-processing process is omitted.

Description

technical field [0001] The invention relates to the field of stainless steel welding, in particular to a self-fluxing welding method for 2507 super duplex stainless steel sheets. Background technique [0002] 2507 (UNS S32750) super duplex stainless steel sheet weldments are mainly used in special industries such as the transportation and handling of acidic dangerous goods, which requires 2507 super duplex stainless steel welded joints to have excellent corrosion resistance. There are two criteria for judging the welding quality of duplex stainless steel welded joints: 1. Whether the weld is well formed; 2. Whether the pitting resistance of the weld (pitting resistance index-PREN value) is close to that of the base metal. The smaller the deformation of the welded joint, the lower the oxidation degree of the weld, and the closer the PREN value of the weld to the base metal, the better the welding quality, and vice versa. At present, due to the difficulty in producing 2507 su...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): B23K9/167B23K9/235C22C38/44C22C38/02C22C38/04
CPCB23K9/167B23K9/235C22C38/44C22C38/001C22C38/02C22C38/04
Inventor 赵志毅栗宏伟薛润东李国平
Owner UNIV OF SCI & TECH BEIJING