Research On The Welding Procedure Of SA335-P92 Steel

P92 steel is a new type of heat-resistant steel which is consisted of martensitic lath structure.The steel is strengthened by M23C6,MX-carbonitrides,Laves phase and solute atoms.It will be widely used in the boiler pipe under the supercritical pressure conditions.The paper has studied the P92 steel welding technology and postweld heat treatment process.The paper has made many examination on the both metallography and mechanical properties to the P92 steel weld joint and also conducted a further study on the toughness characteristics of the weld.The experiment result indicates the welding technology and postweld heat treatment process can make P92 steel weld joint meet the regulation of DL/T868《The code of welding procedure qualification》.This paper point out that impact toughness of the weld increases with the proportion of fine grain in the direction of cracking and the difference of the pipe wall temperature between inside and outside should be reduced when it is postweld heat treatment at the scene.