What is crack metallography
Sep. 18, 2020
What is crack metallography
The cracks produced in the metal solidification process are called hot cracks; the cracks produced after solidification are called cold cracks. Cracks destroy the integrity of the metal. Except for a few that can be removed by timely processing, they will usually expand along the stress concentration area during subsequent processing and use, and eventually lead to cracks.
Hot cracking is when the ingot has not completely solidified or there is a small amount of low-melting phase between the grain boundaries and dendrites. The shrinkage and solidification shrinkage of the metal are hindered when the shrinkage stress exceeds the current metal strength or line. The shrinkage is greater than the elongation of the alloy. According to different locations, thermal cracks can be divided into surface cracks, central cracks, radial cracks and lateral transverse cracks. Thermal cracks usually extend along the grain boundary, with irregular twists and branches, and often branching. There may be an oxide film in the crack or a slight oxidation color on the surface.
