What is the welding performance of 40Cr steel plate?

Welding performance of 40Cr steel plate
It is easy to segregate during crystallization and is more sensitive to crystallization cracks (a kind of thermal cracks). It is easy to crack in the arc crater and the concave part of the weld during welding. The high carbon content makes it easy to obtain a hardened structure (martensitic structure) sensitive to cold cracks during rapid cooling. When the cooling rate of the superheated zone is high, it is easy to form hard and brittle high-carbon martensite to make the superheated zone brittle.
 
Key points of 40Cr steel plate welding process:
1) Generally, welding is carried out under annealing (normalizing) state.
2) Unrestricted welding method
3) Use larger heat input to appropriately increase the preheating temperature. Generally, the preheating temperature and interlayer temperature can be controlled between 250 and 300°C.
4) The welding material should ensure that the composition of the deposited metal is basically the same as that of the base metal, such as J107-Cr
5) Quenched and tempered heat treatment should be carried out in time after welding. If it is difficult to carry out the quenching and tempering treatment in time, intermediate annealing or holding at a temperature higher than the preheating temperature for a period of time can be carried out to eliminate the diffusive hydrogen and soften it. For products with complex structures and many welds, an intermediate annealing can be performed after a certain number of welds have been welded.
Pig iron filing protection swing tempering specification (670±10)℃×2h, heating up with the furnace, (710±10)℃×2h, cooling with the furnace, (670±10)℃×2h, heating up with the furnace, (710±10) )℃×2h, then cool down with the furnace, (670±10)℃×2h, heat up with the furnace, (710±10)℃×2h, cool down with the furnace, a total of 3 cycles, then cool to 550°C, air-cooled out of the furnace. The hardness after treatment is 153HBS.