Nitrogen protection device and method in laser welding process

Abstract

A nitrogen protection device in the laser welding process adopts the structure that nozzles are connected with nitrogen supply conducts, and the nozzles comprise an external nozzle and an internal nozzle. The concrete operation method comprises the following steps: the nozzles are simultaneously arranged inside and outside a welding point of a stainless steel tube; the external nozzle and the internal nozzle are respectively connected with a liquid nitrogen container through the nitrogen supply conducts; the internal and external nozzles are opened at first to allow nitrogen to be jetted on the welding point, and then a laser welding machine is started; the nitrogen supply quantities of the internal and external nozzles are determined by the welding speed and the power of the laser welding machine, and after welding is finished, the laser welding machine is stopped at first and then the internal and external nozzles are closed. The nitrogen protection device has a simple structure and can protect the welding point in real time in the laser welding process of the stainless steel tube so as to prevent the welding point from serious oxidation, guarantee the internal and external brightness of the tube and improve the corrosion resistance, and all detections show that the tube welding quality is high; the nitrogen protection method is simple to operate, saves both time and labor and can be conveniently used by welders of all levels.

Description

technical field

[0001] The invention relates to nitrogen protection in the laser welding process, in particular to a nitrogen protection device and method used in the laser welding process of stainless steel pipes. Background technique

[0002] In the actual production process, the stainless steel pipe is generally welded on the outside of the pipe by laser. After the welding of the stainless steel pipe is completed, the surface of the welded joint often appears the oxidation phenomenon that the groove becomes black. The groove will be deepened during the drawing process, thereby causing a deeper groove at the weld on the surface of the pipe, which not only affects the strength and service life of the stainless steel pipe, but also affects the smoothness of the surface of the pipe body. What's more serious is that after the stainless steel pipe is welded, the inside and outside of the pipe body are black, severely oxidized, poor in corrosion resistance, and have seams and un...

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