Billet surface defects nature and classification
Billet surface morphology is not the only basis for determining ownership of the waste, it is because of the different processes, different process stages, macroscopic morphology of different reasons billet surface defects may be the same, such as surface cracks, both may arise from over-burning, may also arise in the hot brittle, also may be associated with low rolling related. The hair crack, both may produce bubbles in the skin, may also have pores on the surface, but also may be related to the ingot surface inclusions (slag) and surface pits related. Therefore, this article is common billet surface defects with a high degree of generality and practicality. On the difficult surface defects or to sampling, experimental methods and procedures applied in this paper for further analysis in the laboratory characterization.
The surface defects Beiman Special Steel Co., Ltd. Over the years rolling production appeared, based on forensic analysis, according to the defect surface features, shape and metallurgical nature, will be divided into 12 kinds of slab surface defects, which are:
1) longitudinal stress cracking (cis split);
2) hair crack;
3) Internal burnt crack;
4) Surface burnt crack;
5) columnar crystals developed serious cracks caused by burning;
6) hot brittle crack;
7) low rolling crack;
8) scarring crack;
9) cracking five elements caused harm;
10) "grinding cracks";
11) super "white spots" brittle fracture;
12) stress cracking.