Method for welding high-grade wear-resistant steel under protection of carbon dioxide

A technology of gas shielded welding and carbon dioxide, applied in the direction of welding medium, welding equipment, welding equipment, etc., can solve the problems of large hardening tendency, embrittlement, etc., achieve improved impact toughness, simple welding process, and improve welding construction conditions Effect

Active Publication Date: 2012-08-15
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the improvement of wear-resistant steel grade, the content of carbon element in the steel is also increased to 0.24% ~ 0.30%, and Cr, Mo, B and other elements that can improve hardenability are added, and the hardening tendency is relatively large. Under the welding conditions of rapid heating and rapid cooling, it is easy to produce hardened martensite structure, which leads to the generation of welding cold cracks and the embrittlement of welding heat-affected zone

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A carbon dioxide gas-shielded welding method for high-grade wear-resistant steel. The selected degree is HB500 high-grade wear-resistant steel plate, the thickness of which is 25mm, and the combination of thick plates is 25mm+25mm. The size of the test plate is 450mm×400mm×25mm;

[0019] The chemical composition and weight percentage of welding wire are: C: 0.06%, Mn: 1.85%, Si: 0.80%, P: 0.025%, S: 0.025%, and the balance is Fe and unavoidable impurities;

[0020] The gas shielded welding groove adopts asymmetric double-sided X-shaped groove, the groove angle is 60??, the groove gap is 1mm, and the blunt edge is 0mm;

[0021] Grinding and removing the rust and oil stains on the groove surface and the surrounding area within 20mm before welding;

[0022] For fixed point butt welding and bottom welding, the preheating temperature before welding is 120°C, and the preheating range is not less than 75mm on both sides of the welding groove;

[0023] Welding process paramet...

Embodiment 2

[0026] A carbon dioxide gas-shielded welding method for high-grade wear-resistant steel. The selected degree is HB500 high-grade wear-resistant steel plate, the thickness of which is 25mm, and the combination of thick plates is 25mm+25mm. The size of the test plate is 450mm×400mm×25mm;

[0027] The chemical composition and weight percentage of welding wire are: C: 0.15%, Mn: 1.40%, Si: 1.15%, P: 0.020%, S: 0.020%, and the balance is Fe and unavoidable impurities;

[0028] The gas shielded welding groove adopts asymmetrical double-sided X-shaped groove, the groove angle is 60??, the groove gap is 0.5mm, and the blunt edge is 0.5mm;

[0029] Grinding and removing the rust and oil stains on the groove surface and the surrounding area within 20mm before welding;

[0030] For fixed point butt welding and bottom welding, the preheating temperature before welding is 120°C, and the preheating range is not less than 75mm on both sides of the welding groove;

[0031] Welding process p...

Embodiment 3

[0034] A carbon dioxide gas-shielded welding method for high-grade wear-resistant steel. The selected degree is HB500 high-grade wear-resistant steel plate, the thickness of which is 25mm, and the combination of thick plates is 25mm+25mm. The size of the test plate is 450mm×400mm×25mm;

[0035] The chemical composition and weight percentage of welding wire are: C: 0.10%, Mn: 1.55%, Si: 0.95%, P: 0.015%, S: 0.010%, and the balance is Fe and unavoidable impurities;

[0036] The gas shielded welding groove adopts asymmetrical double-sided X-shaped groove, the groove angle is 60??, the groove gap is 1mm, and the blunt edge is 0.5mm;

[0037] Grinding before welding to remove rust and oil within 20mm around the weld;

[0038] For fixed point butt welding and bottom welding, the preheating temperature before welding is 120°C, and the preheating range is not less than 75mm on both sides of the welding groove;

[0039] Welding process parameters: welding current 300A, arc voltage 32V,...

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Abstract

The invention belongs to the technical field of welding steel materials and discloses a method for welding high-grade wear-resistant steel under protection of carbon dioxide. The method comprises the following steps of: utilizing a high-grade wear-resistant steel plate with the hardness grade of HB500 and the thickness of below 25mm, combining and butt jointing the steel plates with the same thicknesses; according to different requirements of a structure on mechanical property, respectively selecting CO2 gas and a welding wire with the extension strength Rm of larger than or equal to 500MPa or the extension strength Rm of larger than or equal to 690MPa; selecting the welding wire with the extension strength Rm of larger than or equal to 500MPa, pre-heating to 120 DEG C before welding when butt welding and back welding are performed on a fixed point; continuously welding, wherein the temperature of an interval between filling and cap weld welding beads is not lower than 120 DEG C and is not higher than 200 DEG C, and welding heat input amount is controlled within 8-20KJ/cm in welding; or selecting the extension strength Rm of larger than or equal to 690MPa, pre-heating to 150 DEG C before welding when butt welding and back welding are performed on a fixed point; and continuously welding, wherein the temperature of an interval between filling and cap weld welding beads is not lower than 150 DEG C and is not higher than 200 DEG C, and welding heat input amount is controlled within 8-20KJ/cm. The method for welding high-grade wear-resistant steel under the protection of the carbon dioxide, disclosed by the invention, ensures that a welding joint has higher strength so that a welding bead has excellent anti-cracking performance, the welding joint has higher low-temperature impact toughness storage and safety margin, the construction condition is modified and the production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of iron and steel material welding, and relates to a carbon dioxide gas shielded welding method for high-grade wear-resistant steel with a hardness level of HB500. Background technique [0002] With the accelerated construction of my country's infrastructure and the implementation of the western development strategy, the demand for wear-resistant steel in industries such as cement building materials, metallurgical mines, and engineering machinery has gradually increased, and the requirements for the strength and hardness of wear-resistant steel have also tended to be higher. High level, which is represented by high-grade wear-resistant steel with a hardness of HB500. With the improvement of wear-resistant steel grade, the content of carbon element in the steel is also increased to 0.24% ~ 0.30%, and Cr, Mo, B and other elements that can improve hardenability are added, and the hardening tendency is relatively...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K9/16B23K9/23B23K35/30B23K103/04
Inventor 李丽尹雨群吴年春汪晶洁
Owner NANJING IRON & STEEL CO LTD
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