Nodular castings will have defects similar to pores and dirty eyes, and some of them are on the processing surface. It is a pity that such defective products are scrapped. The following methods
might help you.
1. Clean up the defects;
2. Use oxygen to burn the defect to the critical melting temperature;
3. Pour molten iron of the same grade on the defect;
4. Keep 900 degrees Celsius for one hour;
5. Cool down to 500 degrees in 2 hours;
6. Reduce to room temperature to room temperature.
Another way:
1. Clean up the defects;
2. Use oxygen to burn the defect to the critical melting temperature;
3. Repair welding with cast iron electrode to qualified;
4. Use oxygen to keep the repair weld at 900 degrees and then put it in the furnace for 1 hour;
5. Cool down for 2 hours to 500 degrees Celsius and bring it out to room temperature.
