Friction stir welding method for ferritic/austenitic dissimilar steels

A technology of friction stir welding and friction stir, which is applied in welding equipment, welding/welding/cutting items, non-electric welding equipment, etc. It can solve problems such as slag inclusions and thermal cracks, and achieve small post-weld stress, good performance, and high automation Effect

Inactive Publication Date: 2016-05-25
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The invention provides a friction stir welding method suitable for ferritic / martensitic steel, which optimizes the parameter conditions for obtaining good-quality welds, and effectively solves the problem of coldness easily caused when fusion welding is used to weld dissimilar steels. , thermal cracks, slag inclusions and other issues

Method used

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  • Friction stir welding method for ferritic/austenitic dissimilar steels

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] use figure 1 The steps shown are for friction stir welding of ferritic / austenitic dissimilar steels. There is no need to preheat the steel plate to be welded before welding, and no heat treatment is required during the welding process; the thickness of the selected ferritic steel plate is 1.5mm , the thickness of the austenitic steel plate is 1.6mm; the diameter of the shaft shoulder is 10mm, the diameter of the end of the stirring needle is 2mm, the diameter of the root is 6mm, and the length is 1.3mm; the tapered stirring needle with a flat end face is used, and the austenitic steel is used as the forward side. The ferritic steel is used as the retreat side, the stirring head is located on the side of the austenitic steel, the distance between the center of the stirring head and the butt joint surface, that is, the offset is 0mm, the inclination of the stirring head is 2.5°, and the welding is carried out along the direction of the weld; press down The amount is 0.1mm...

Embodiment 2

[0025] use figure 1 The steps shown are for friction stir welding of ferritic / austenitic dissimilar steels. Preheating of the steel plates to be welded is not required before welding, and no heat treatment is required during welding. The thickness of the selected ferritic steel plates is 2 mm. The thickness of the austenitic steel plate is 2.2mm; the diameter of the shoulder is 12mm, the diameter of the tip of the stirring pin is 4mm, the diameter of the root is 8mm, and the length is 1.8mm; The element steel is used as the retreat side, the stirring head is located on the side of the austenitic steel, the distance between the center of the stirring head and the butt joint surface is 0.2mm, the inclination of the stirring head is 1.5°, and the welding is carried out along the direction of the weld; press down The amount is 0.2mm; the travel speed of the stirring head is 50mm / min, and the rotation speed is 500rpm; after the welding is completed, the fixing device is loosened af...

Embodiment 3

[0027] use figure 1 The steps shown are for friction stir welding of ferritic / austenitic dissimilar steels. There is no need to preheat the steel plate to be welded before welding, and no heat treatment is required during the welding process; the thickness of the selected ferritic steel plate is 3.8mm , the thickness of the austenitic steel plate is 3.9mm; the diameter of the shaft shoulder is 18mm, the diameter of the end of the stirring needle is 5mm, the diameter of the root is 9mm, and the length is 3.6mm; the flat-end tapered stirring needle is used, and the austenitic steel is used as the forward side. The ferritic steel is used as the retreat side, the stirring head is located on the side of the austenitic steel, the distance between the center of the stirring head and the butt joint surface is 0.3mm, the inclination angle of the stirring head is 3°, and the welding is carried out along the direction of the weld; The pressure is 0.3mm; the travel speed of the stirring h...

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Abstract

The invention relates to friction-stir welding method of ferrite / austenite dissimilar steel, and belongs to the technical field of welding of metal materials. The method comprises the steps that a ferrite steel plate and an austenite steel plate are fixed in an abutting-joint manner through a fixing device and are fixed to a friction-stir welding device through a clamp; the distance from a stirring head of the friction-stir welding device to an abutting-joint surface is set, that is, the offset amount and the shaft shoulder pushing amount are set; and the inclined angle, the rotating speed and the advancing speed of the stirring head are adjusted, and then welding is carried out. According to the method, in the welding process, heat input is small, an overheated area existing in fusion welding cannot be generated, and common defects, such as impurity blending and cold and heat cracks, do not exist. A welding joint with the more excellent performance can be obtained. The technology problem of welding of a dissimilar steel plate is solved.

Description

technical field [0001] The invention relates to the technical field of metal material welding, in particular to a friction stir welding method for ferrite / austenite dissimilar steels. Background technique [0002] The welding of ferritic / austenitic dissimilar steels involves many industries such as nuclear reactors and thermal power generation, and plays an important role in the national economy. However, for the current welding technology, the welding of dissimilar steels is still a difficult point. This is due to the great differences in the chemical composition, mismatch of thermophysical properties and chemical properties of dissimilar metals. During the welding process using traditional welding methods (such as fusion welding), thermal cracks in the weld zone, thermal Cold cracks in the affected area, carbon migration, uneven microstructure, and coarse-grained areas are prone to occur, resulting in poor mechanical properties of welded joints and failures (I. Hajiannia,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K20/12B23K20/227B23K103/02B23K101/18
CPCB23K20/122B23K20/227B23K2101/18B23K2103/02
Inventor 常永勤李晓林张静梁亚超龙毅
Owner UNIV OF SCI & TECH BEIJING
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