Structure of the transition zone in weld seams of different steels welded together

Conclusions

• 1. Carbon increases the stability of the austenite in the transition zone; in welded samples of base metal containing 0.01 and 0.18% C the austenite in the base metal decomposes with formation of a structure corresponding to that resulting from quenching.

• 2. Carbides are formed from austenite and alloyed martensite in the transition zone during isothermal heating at temperatures ensuring high diffusional mobility of carbon atoms and carbide-forming elements. The precipitation of carbon from the austenite and martensite lattices during crystallization of the carbide phase favors pearlitic and intermediate transformation of these phases.