The casues leading to weld seam cracking on thermocouple sleeves used for main steam pipeline of unit no.1 in one power plant of Henan Province have been analysed

it is believed that the causes of cracking are as follows:the base metal hasn't warmed up

and the heat treatment hasn't been carried out

as well as defects and stress existing in welding

etc..For this

the welding process of M+A different steels has been worked out

such as:selecting Inconel type welding electrode;the base metal must be warmed up to 250 ℃~300 ℃;in the process of welding

adopting small criterion weld as possible;after welding

the welded metal should be applied with thermal insulation for being slowly cooled;and choosnig suitable temperature for heat treatment etc..