Abstract
As the result of a few examination about the joint strength of ferritic spheroidal graphite cast iron in insert-type electron beam welding, we found out that the mean hardness of fusion zone by 3 passes welding increased markedly in the case of SUS 304 insert (about Hv 618) compared with SUS 310 S insert (about Hv 152). Concerning the tensile strength of welded joint, SUS 310 S was superior in joint strength to SUS 304 and pure nickel. And especially in the case of SUS 310 S, about 100 % joint efficiency was obtained. As to the impact values of base metal and insert-type welds, higher toughness was shown in the case of base metal than insert-type welds in high temperature, but same tendency was shown for both base metal and insert-type welds in low temperature. As the result of the fatigue tests for both SUS 304 and SUS 310 S welded joints, generally base metal was fractured under repeated stress of 225∼350 MPa, while welds had sufficient fatigue strength. And the fatigue limit of 200 MPa was shown for both. Moreover, when the joint strength of SUS 304 welds using as-cast material was compared to that using annealed material, the static strength of annealed material was superior to that of as-cast material and, regarding dynamic strength, as-cast material showed superior joint performance.
