Eutectoid Transformation

The isothermal transformation of one solid phase into two different finely dispersed solid phases upon dropping below a specific temperature. The classic example is the formation of pearlite from austenite in the iron system.

At its core, this is the transformation of austenite during cooling. When you weld steel, you heat the zone so much that the structure transforms back into austenite. How it cools afterwards determines the result. If you let it cool slowly, you get a soft, tough structure. If you cool too fast, it becomes hard and brittle, and it can crack quickly. The trick is to control the cooling so that you get a structure that suits the application – usually you want a good compromise between hardness and toughness.

MetallurgieSchweißtechnik