Blowhole segregation at the ingot centre or below the ingot surface

Blowhole segregation at the ingot centre or below the ingot surface - ESR ingot defects

Figure 1: Blowhole segregation at the ingot centre or below the ingot surface.

Defect name: Blowhole segregation at the ingot centre or below the ingot surface
Record No.: 35
Type of defect (Internal/Surface): Internal
Defect classification: ESR ingot defects
Steel name: Steel
Steel composition in weight %: No data.
Note: Definition and appearance: Local pipe-like differences in concentration.
Cause/Occurrence:
- Excessive hydrogen, nitrogen or oxygen content of the electrode
- Use of moist slag
- Excessive FeO content in the slag
- Insufficient deoxidation of the electrode material
- Use of rusty, oily or moist chips for start-up
- Inappropriate start-up practice.
Identification: Only becomes apparent during the subsequent processing stages.
Location: Over the entire ingot length.
Possibility of mistaken identity: None
Avoidance or possible corrective action:
Avoidance possibilities:
- Use of dry slags of appropriate composition
- Use of vacuum-treated electrodes with controlled deoxidation
- Use of dried or annealed chips for start-up Correction possibilities
- None.
Reference: Not shown in this demonstration version.