rheostat---- The composition of chemical gradesmajor%impurity%NiCuFeMnCSiTi6J4039-41remaining0.51-20.150.20.1 The result of tensile test grades diametermm Tensile strength (N/m) elongationM(sofe)Y(hard)M(sofe)Y(hard) 6J400.05--0.1 8----0.1--0.5 12----0.50-- 15----