Method for welding copper oxygen lance end for steelmaking with steel pipe sub

Abstract

A method for welding a copper oxygen lance end for steelmaking with a steel pipe sub uses a medium frequency induction heating device, the copper end and the inner and outer steel pipe sub are rapidly heated by two induction heating coils to respectively reach different optimal preheating temperatures in a short time and then are welded, and induction heating and isothermal annealing treatment is performed for a welding line after welding to sufficiently eliminate residual stress. By adjusting the current strength of an induction heater, the preheating temperatures of the copper end and the inner and outer steel pipe sub can be precisely regulated and controlled according to process requirements, heating is rapidly performed, an oxidation layer is decreased, the strength of the welding line is improved, and production efficiency is improved while the welding quality of the oxygen lance end is ensured.

Description

technical field [0001] The invention relates to a workpiece welding method, in particular to a method for welding a copper end of an oxygen lance used for steelmaking and a short joint of a steel inner pipe or an outer pipe. Background technique [0002] The copper end of the oxygen lance nozzle used in steelmaking is integrated with the short joints of the steel inner and outer pipes by argon arc welding. In order to reduce the welding stress and increase the width of the transition zone of the weld alloy composition to ensure the welding quality, the current method is to preheat the machined copper end and the short joint of the steel pipe to about 600 in the electric furnace. ℃, then take it out from the electric furnace, install it on a special argon arc welding machine for welding, and complete the manufacturing of the product after cooling after welding. The disadvantages of this processing method are as follows: First, the preheating process is heating and heat p...

AI Technical Summary

Problems solved by technology

The disadvantages of this processing method are as follows: First, the preheating process is heating and heat preservation in an electric furnace, which takes about one hour. Due to the long heating time, the oxide layer on the outer surface of the workpiece is thick, and the slag inclusion in the weld seam is serious, which affects the weld seam. Mechanical properties; second, the copper end and the short joint of the steel inner and outer pipes are installed at a high temperature, which is difficult for workers to operate, and there is a danger of being scalded; third, the difference in melting point between copper and steel is about 400 ° C, and the difference in thermal conductivity is large , and the same preheating temperature makes the workpiece prone to cold shut defects after welding; the fourth is that effective heat treatment is not carried out after welding, the residual stress is large, and the weld strength is low, which affects the quality of the oxygen gun head

Images