Degenerated Pearlite Microstructure
An atypical, disrupted form of pearlite in which the lamellar structure is fragmented due to thermal influences or unfavorable cooling parameters. This results in altered strength properties.
Pearlite is a mixed structure of ferrite and cementite, present in lamellae. If you cool too quickly during welding or distribute the heat unevenly, this structure can decompose or degenerate. The result is a tougher but softer and more crack-prone material that will cause you trouble in the long run. To prevent this, you have to control the cooling. Rapid cooling is the main enemy, so don't leave the part in a draft or cool it with compressed air. Also, adapt your heat input to the material and ensure proper preheating if the material is thick or sensitive. If you control the cooling time, the structure will remain stable and the weld will hold.