RU2239531C2 - Thick-wall parts welding method - Google Patents

Abstract

FIELD: processes for welding thick-wall parts of hard-to-weld high-alloy high-strength materials, possibly in different branches of machine engineering for making important constructions operating in aggressive gases and liquids at high and low temperatures.

SUBSTANCE: additive material in the form of thin-wall members with thickness equal to thickness of welded edges or more than it is tack welded to surfaces of edges of welded parts. Butt is assembled on backing without gap. Compression load is applied to butt indirection normal to it. Then additive material is fused by means of narrow unfocused electron beam in modes providing minimum fusion of near-seam zone and welding is realized at the same modes.

EFFECT: possibility for providing high-strength welded joint without cracking and flaws.

2 dwg, 1 ex

Description

The invention relates to the welding of thick-walled parts from difficult to weld, high alloy, high strength materials and can be widely used in various industries in the manufacture of critical structures operating in aggressive liquids and gases at high and low temperatures.

A known method of producing a welded joint a, in which the edges are grooved and metal beads are deposited onto the bevels of the edges, is a filler material, and in the process of filling the grooves, the gaps between the rollers are melted (SU 1127727, 23K 33/00, 12/07/1984).

However, the known method is time consuming and is applicable only to certain types of products. The results of the verification of the method when welding products from high alloy steels did not give positive results.

A known method of welding corner joints of high strength steel, in which, at least partially, pre-clad the welded surface with low carbon steel with a thickness of 1.5-3 mm, after which welding is performed in the cladding zone (JP No. 50-2868, 01/29/1975, B 23K 31/00).

However, when welding using this method, it is impossible to provide a strictly dosed amount of the additive during welding.

Closest to this invention is a known method of welding thick-walled parts from difficult to weld, high alloy, high strength materials, which is carried out using a strictly metered filler metal. As the filler metal, two rings are used, one of which is inserted into the gap between the edges to be welded and melted in the first pass, and the second ring is melted in the second pass, forming a weld reinforcement (FR 2527491, 23K 33/00, 12/02/1983) .

This method is also quite time-consuming, while it is not acceptable for compounds with a complex configuration of parts, the degree of alloying of the welded edges to suppress cracking is different due to the possible displacement of the additive to one of the welded edges.

The objective of the invention is to obtain high-quality welded joints from hard-to-weld steels and alloys with desired strength properties.

For this, in the method of welding thick-walled parts from difficult to weld, high alloy, high-strength materials, which is carried out using a strictly dosed filler metal, filler metal in the form of thin-walled elements with a thickness equal to or greater than the thickness of the welded edges is seized to the surfaces of the edges of the welded parts, the joint is assembled without a gap on the lining, apply a compressive load to the joint in the direction perpendicular to it, melt the filler metal by narrow defocusing electron beam in the modes providing minimum fusion of the heat-affected zone, and then welding in the same modes.

The drawings show the scheme of welding.

Example.

Welded parts made of high-strength steel VNS25 30 mm thick. An element of 12X18H10T material with a thickness of 0.8 mm and a height equal to the thickness of the welded edge or greater by 0.5-1 mm by spot welding was welded to each welded edge. Assembling the parts to be welded was performed end-to-end without a gap with a load perpendicular to the joint axis of 200 kg. Welded by an electron beam in two passes on a lining 15 mm thick. In the first pass, the filler metal was melted by a narrow defocused electron beam in the modes providing the minimum fusion of the heat-affected zone, the focus was shifted by 2-3 mm (Fig. 1). In the second pass, the welding itself was carried out in the same modes, while the focus was shifted by 5-10 mm (Fig. 2). After welding, the lining was cut off. X-ray inspection of the weld showed no cracks.

Claims (1)

A method of welding thick-walled parts from difficult-to-weld, high-alloy, high-strength materials, which is carried out using a strictly metered filler metal, characterized in that the filler metal in the form of thin-walled elements with a thickness equal to or greater than the thickness of the welded edges is seized to the edge surfaces of the welded parts, the joint is assembled without the gap on the lining, is applied to the joint in the direction perpendicular to it, compressive load, perform the melting of the filler metal with a narrow ra a focused electron beam on modes providing minimal heat affected zone melting, and then welding at the same conditions.

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