ZG15 Cr2 Mo1 is the common material used for large castings in thermal power plants. The welding repair technology of ZG15 Cr2 Mo1 main steam combined regulating valve in the thermal power plant is introduced

including the removal of defects

welding preparation

heat treatment procedure

welding technology and inspection. The main steam combined regulating valve is repaired by manual metal arc welding with ENi Cr Fe-2 electrode

single U groove and preheating temperature of 100 ℃～150 ℃. To get a good result

the manual metal arc welding with low current is used for the backing weld

and the multi-layer and multi-pass welding is also used for continuous welding. After welding

the penetration test and hardness test are carried out

no effect is found

and the hardness test results also meet the standard requirements

the results show that the technology can repair the large castings of ZG15 Cr2 Mo1 in thermal power plants.