Non-penetration copper build up welding method on D406A steel surface

Abstract

The invention discloses a non-penetration copper build up welding method on a D406A steel surface. The non-penetration copper build up welding method on the D406A steel surface is characterized by including the following steps: (1) conducting thermal refining process on D406A steel, (2) soaking and fixing the D406A steel which is processed through thermal refining in the step (1) in quenching liquid, keeping the surface to be welded above the liquid surface of the quenching liquid, or spraying the quenching liquid to a reverse face of the to-be-welded surface of the D406A steel, and (3) conducting copper build up welding on the to-be-welded surface of the D406A steel by using CuSi3 welding wires through the cold metal transfer (CMT) welding method. According to the non-penetration copper build up welding method on the D406A steel surface, heat input is extremely low in welding process, a heat affected zone is extremely small, diffusion amount of copper to a substrate is fewer and even, diffusion depth is not more than 0.1 millimeter, interfaces between different kinds of materials are distinct, neat and regular, no burning loss occurs, and high strength metallurgical bonding is achieved and influence from the welding process on steel substrate performance is reduced at the same time.

Description

technical field [0001] The invention relates to the field of metal processing, in particular to a welding method for depositing copper without penetration on the surface of D406A steel. Background technique [0002] With the development of the aerospace industry, the application of ultra-high-strength steel is becoming more and more extensive. D406A steel is a kind of ultra-high-strength steel developed by my country. It is widely used in solid rocket motor shells. In order to improve the surface resistance of steel Wear performance, usually need to deposit a thinner copper layer on the surface of the D406A steel substrate, such as the exposed section of the combustion chamber shell, in order to improve its launch guidance performance and avoid damage to the guide rail during launch, it is necessary to deposit on the steel substrate surface of the front and rear sliders The copper layer is welded to achieve metallurgical bonding between the deposited layer and the steel substr...

AI Technical Summary

Problems solved by technology

However, the D406A steel has a high carbon content, coupled with the effect of alloying elements, the heat sensitivity of the steel is high, the hardening tendency is increased, the weldability is poor, and serious welding defects such as cold cracks are prone to occur after welding; and the steel matrix is ​​now In the quenched and tempered state, the copper layer is surfacing on its surface. It is required to minimize the welding heat input during the surfacing process, and reduce the influence of heat diffusion on the performance of the substrate.

[0003] For the above situation, researchers at home and abroad have conducted research on the process of depositing copper on the surface of steel substrates using arc surfacing technology in the early stage. Inhomogeneity, the matrix is ​​easily melted and burned, and the performance of the product after welding is greatly reduced, which has become a technical difficulty affecting the surfacing process; Methods such as medium deposition welding and fusion casting deposition welding have achieved surface deposition without penetration, but the deposition process is cumbersome and the efficiency is low; while CMT welding technology (cold metal transition welding technology) is based on molten electrode argon arc welding. A new type of welding technology, the fundamental difference between it and CIGA welding is that the arc is quickly extinguished when the welding wire droplet transition short-circuits with the workpiece after the arc is started, and the welding wire is withdrawn at the same time, and then the arc is restarted, and the cycle is repeated to form a reliable connection , although its welding heat input is low, it still has a certain influence on the properties of the matrix