How to weld the WC9 grade casting if heavy crack developed?

To weld WC9 grade casting with heavy cracks, first ensure proper surface preparation by cleaning the area to remove any contaminants. Use a suitable filler material that matches the alloy composition, typically a nickel-based or low-alloy steel electrode. Preheat the casting to a temperature of about 300-500°F (150-260°C) to reduce thermal shock and minimize further cracking. Finally, employ a controlled cooling process post-welding to reduce residual stresses and prevent new cracks from forming.