Method for improving abrasion resistance of stir head for stir-friction welding of high-strength aluminum alloy

Abstract

The invention relates to a method for improving abrasion resistance of a stir head for stir-friction welding of a high-strength aluminum alloy. The method aims at solving the problems that abrasion resistance of a stir head for stir-friction welding of the high-strength aluminum alloy in the prior art is poor. According to the method for improving abrasion resistance of the stir head for stir-friction welding of the high-strength aluminum alloy, strip-shaped laser cladding abrasion-resistant layers are evenly cladded on the surfaces of a shaft shoulder and a stir pin of the stir head through the laser cladding technology, wherein the strip-shaped laser cladding abrasion-resistant layers are formed by mixing a laser clad alloy and WC particles. The weight percentage of the WC particles and the laser clad alloy is that the WC particles counts for 10-20% of the total weight, and the laser clad alloy comprises, by weight, 5-15% of Cr, 5-15% of Co, 2-5% of Si, 3-6% of W and 1-4% of Pd, and the remaining is Ni. The surfaces of the shaft shoulder and the stir pin of the stir head are heated through laser beams with high energy density to form the strip-shaped laser cladding abrasion-resistant layers, the width of the strip-shaped laser cladding abrasion-resistant layers is 2-3mm, the height is 0.05-0.2mm, and the number of strips on the surfaces of the shaft shoulder and the stir pin is 3-8.

Description

technical field [0001] The invention relates to a method for improving the wear resistance of a stirring head of a friction stir welding high-strength aluminum alloy, belonging to the technical field of welding and connection. Background technique [0002] Aluminum alloy has the advantages of low density, high strength, good thermal conductivity, corrosion resistance, easy forming and recycling. Body, wheel hub, etc. are developing towards the direction of body parts and structural parts, becoming the second largest automotive material after steel. The increasing application of aluminum alloys in automobiles is the development trend of the automobile industry and the demand of social development. At present, the aluminum alloys suitable for automotive structural parts are mainly heat-treated high-strength aluminum alloys, including Al-Mg (5000 series), Al-Mg-Si (6000 series) and Al-Mg-Zn (7000 series). Manufacture body parts and structural parts with high strength requirem...

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Problems solved by technology

[0007] It is difficult for a stirring head made of a single metal material to meet the requirements for high temperature thermal stability and wear resistance at the same time, and the wear resistance of metal materials is very limited. The wear of the stirring head shaft shoulder and stirring needle will inevitably make the mechanical force and frictional heat change, affecting the reliability and stability of subsequent welded joints

However, the composition, structure, and performance of the stirring head shaft shoulder and clamping part of the double-material combination are quite different from the stirring needle material, and the connection interface changes suddenly, resulting in poor impact resistance of the joint; at the same time, the stirring head of the double-material combination only considers improving the stirring The wear resistance of the needle does not take into account the function and wear resistance of the shaft shoulder. The wear resistance of the shaft shoulder is lower than that of the stirring needle. The wear resistance of the two does not match. The shaft shoulder wears before the stirring needle. The result is Premature failure of the mixing head due to wear on the shoulder

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