Nodular cast iron will inevitably produce casting defects in production .It can be use welding repair according to the technical requirements , however, nodular cast iron with high carbon content, poor welding performance, easy to produce white structure and crack during welding process. This paper study on the QT400-18 iron welding process. formulate strict welding process, compared with the matrix material. The results show that the hardness is slightly high and not suitable for reinforcing treatment for machining surface after selected Z408 welding rod . The hardness was closed to the base material selected Z308 welding rod , it can be complement treatment for machining surface, tensile strength and the yield strength were closed to the base material after using Z408 welding rod and Z308 welding rod , the welding quality does not affect the properties of castings.%球墨铸铁铸造生产中难免产生铸造缺陷，根据铸件技术要求可以采用焊补修复。然而，球墨铸铁含碳量高，焊接性能差，焊补过程中易产生白口组织和裂纹。通过对QT400-18球墨铸铁焊补工艺进行研究，制定严格的焊补工艺，通过与母材对比结果表明，选用Z408焊补后的硬度稍高，不适合用于加工面的焊补处理，Z308焊条焊补后的硬度与母材接近，可以用于加工面的焊补处理，Z308焊条和Z408焊条焊补后的抗拉强度和屈服强度基本与母材一致，不影响铸件的使用性能。
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