C Mn Si S P 0.12 0.3-0.6 ≤0.35 ≤0.035 ≤0.040 Test item Tensile strength MPa Yield strength MPa Elongation Impact value(J) Guaranteed ≥420 ≥330 ≥22 ≥47 Tested 490 400 27 60 X-ray radiographic inspection: grade Weld rod diameter(mm) 2.0 2.5 3.2 4.0 5.0 Welding current(A) 35-60 55-95 90-140 140-200 190-240