304LN/Inconel 690 Thick Wall Component Laser Welding Process Research

In recent years,with the need of economic development,it is an important developing strategy for our country to devote major efforts to developing nuclear power.In the development of nuclear power manufacturing industry we encounter difficulties in different respects,such as material,welding,machining,etc.Among them up to now the thick wall component welding is a topic which is inevitable and difficult to handle in nuclear power manufacturing.This article is for thick wall component welding between 304 LN and Inconel 690 of control rod drive mechanism,one of the main equipment for nuclear island.Respectively use GTAW and narrow-gap laser welding process?narrow-gap laser welding process with filler metal,and fill in ERNiCr-7A wire.A variety of welding testing has been carried out for this weld,by the study of welding process and parameters we analyze surface shaping of the welds and microstructure of welds and fusion zone.Research the effect on weld forming and properties by welding process and parameters.The main content of weld and base metal is austenite.At the same time by RT,mechanical testing and stereoscanning of welds under the condition of different testing data,provide beneficial theoretical base to improve welds' property.And determine the process and parameters to achieve optimized welding organization,to form good metallurgical bonding between weld and base metal,at the same time to reduce the deformation during welding.The testing results show that by narrow-gap laser welding process for the joint of 30 mm thick 304 LN and Inconel 690,filling in ERNiCrFe-7A wire,with 10°chamfer,20 mm defocusing amount,4KW power,42cm/min welding speed and 150cm/min wire feed rate,we can obtain the weld with optimized microstructure and mechanical properties.Good safeguard is provided for the safe running of nuclear island equipment.