Comparison of strength characteristics of nodular graphite cast iron welded joints by various welding processes

Abstract

On the welding of the nodular graphite cast iron, many researches have been carried out until now. The shielded metal arc welding and TIG welding using the filler material with nickel, and oxy-acetylene welding have been recommended as a welding process of the nodular graphite cast iron. And, the execution of preheating, postheating, peening and interlayer thermal management is required in the welding procedure. But the expertise, experiences and high skills are needed to carrry out these executions. Thus, it is the fact that these executions are too complicated to be spread widely.In the research on the welding of the nodular graphite cast iron, there are many papers that heat input, interlayer thermal management, welding materials and welding conditions are examined and the results are discussed. However, it is hard to find a paper that compares the welding results by using several kinds of welding process and welding materials.In this study, 9 kinds of weld test pieces are produced by using 4 kinds of generally used welding process. And the welding of nodular graphite cast iron is examined not only on its hardness, tensile strength and bending strength, but also its workability, efficiency and cost. As we emphasized its practicability, we didn't consider preheating, postheating, peening and interlayer thermal management.