| 摘要 |
PROBLEM TO BE SOLVED: To develop a welding rod and a joining method by welding wherein chill is restrained in welding between a spherical graphite cast iron member and a mild steel member. SOLUTION: A rod core wire is made of hyper eutectic piece-like graphite cast iron, a metal or alloy such as Al and Ni which promotes to graphitize cast iron is used as an insert material an inoculant such as Ca-Si-Ba and RE-Ca- Si is fitted inside a welding groove to weld. After welding, a heat generating and keeping agent is sprinkled on a bead part or the like to execute an after- heat treatment. The rod core wire is composed of, by mass, 3.3-3.8% C, 4.0-5.0% Si, and a CE value of C+0.31×Si is preferably 4.8-5.3. The adding quantity of the insert material is preferably 0.3-1.5 mass % of the weight of the rod core wire penetrated into a weld zone. Also, repairing by welding for spherical graphite cast iron is executed by the above welding method using the above welding material. Thus, welding for the spherical graphite cast iron which have been conventionally difficult is allowed.
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