Binary iron-carbon phase diagram

A graphical representation of the thermodynamic equilibrium states of iron-carbon alloys as a function of temperature and concentration. It forms the fundamental basis for understanding heat treatments and phase transformations in steels.

The iron-carbon diagram shows you which structures in steel are stable at what temperature. This is important to understand what happens during welding and subsequent cooling in the workpiece. If you don't control cooling, the structure can become too hard or brittle, which causes cracks. In practice: after welding, you have to decide depending on the steel grade whether to stress-relieve anneal or normalize the weld to get the desired properties.

MetallurgieSchweißtechnik