How to repair cracks in pig iron depends on the importance of the workpiece you are welding, such as ordinary household necessities such as cast iron tools, furnace rods, etc. For these types of things, use ordinary 506 welding rods before welding. Heat it to 600 degrees until it turns red, then quickly weld it and then use a pile of lime to keep it warm and slowly cool it down.
If it is a pig iron crack on important equipment, considering the importance and success rate, it is recommended to use WEWELDING777 cast iron electrode with high crack resistance for welding. This type does not require preheating and insulation. Generally, such as cast iron engine water channel cracks, You can also use carbon steel plates to fill the pig iron holes after pounding the cylinder. You will use this special cast iron welding rod. I wish you good luck!