martensitic steel containing Cr of low carbon

摘要

martensitic chromium steel containing low carbon content comprising: from 0.02% to 0.10 mass% carbon and 0.02% to 0.10 mass% of nitrogen, the total content of carbon and nitrogen 0.08% to 0.16% by mass; 0.5 mass% or less of silicon; 0.1 mass% or less of aluminum; 0.3% to 3.0 mass% manganese; 10.5% to 13.5% by mass of chromium; 0.05% to 0.60% by mass of niobium and 0.15% to 0.80% by mass of vanadium, the total content of niobium and vanadium 0.25% to 0.95 mass% ; 0.02% to 2.0 mass% of nickel; 1.5% by mass or less of copper; optionally further comprising one or more elements selected from 0.1% to 2.0 mass% of molybdenum, tungsten and tantalum, 0.0030% to 0.0002% by mass of calcium and magnesium, and 0, 0002% to 0.0060% by mass of boron; comprising balance iron and incidental impurities, wherein the steel a value of Fp of 80.0 to 96.0, a hardness after tempering of HRC 31 to 40 and a hardness after tempering at 700oC for one hour of HRC 31 or more , the value of Fp by the equation (1) is represented: Fp value = -230C + 5Si - 5Mn - 6Cu + 10CR - 12Ni + 32Nb + 22V + 8W + 10Ta + 12th + 40Al - 220N (1) in the that the symbols of elements indicating the contents of respective elements (mass%).