About cast iron welding issues
Thread Content
When welding cast iron in our company, we used medium carbon steel electrodes as welding materials. After welding, we drilled holes in the weld bead. The hardness was very high and we couldn’t drill. I don’t know why? Therefore, the following problems arise: 1. Is it reasonable to use medium carbon steel electrodes for welding? 2. If it is unreasonable, what welding rod should be used? Why is the hardness of medium carbon steel electrodes so great after welding? Please ask experts in this field for answers! Thanks
Preparation work must be done to ensure that the welding current is appropriately small and short, and the welding is intermittently dispersed and hammered immediately after welding! 0. Welding with Z308 small diameter electrode ； 1. Stop cracks and prevent crack expansion ； 2. Before welding, the rust, oil, moisture, etc. on the surface of the workpiece must be strictly cleaned. 3. Use as little current as possible for welding. 4. Use short-section, intermittent, and dispersed welding when welding.: The length of each weld should generally not exceed 20 to 40 mm. After each weld, the next weld should be welded as far away as possible to avoid excessive local temperature and increased stress. 5. Faster welding speed and short arc operation should be used during welding, and the lateral swing of the electrode should be small during the welding process. 6. When welding, after each welding seam, you should immediately use a pointed hammer with a rounded corner to quickly hammer the weld metal until dense pits appear on the welding seam. You should wait until the temperature of the welding seam and the surrounding area cools down to not hot (50~60℃) before welding the next one.
For less important occasions, J507 can be used for welding.