Degenerated pearlite
Degenerate pearlite is an irregular, fragmented microstructure with dissolved or coarsened cementite lamellae. It forms due to unfavorable cooling conditions or thermal pretreatments and leads to poor strength and increased risk of cracking.
Physical-Chemical Mechanism of Action
Pearlite forms when steels cool, through the simultaneous formation of austenite and cementite. Under unfavorable cooling conditions or thermal pretreatments, the austenite can transform too quickly, leading to dissolution or coarsening of the cementite lamellae.
Metallurgical Relevance & Welding Risks
Degenerate pearlite reduces the strength and toughness of the steel. It increases the risk of cracks and hot cracks, since the material is less ductile. Mechanical performance is compromised, which can lead to earlier failure under load.
Shop Practice & Action Guidelines
To avoid degenerate pearlite, ensure controlled cooling after welding. Use suitable shielding gases and protect the steel from thermal shocks. If suspected, run a metallurgical test and consider rework or hardening methods.