Double phase stainless steel strip for steel belt

A dual-phase stainless steel strip for use as steel belts, which has:

• a chemical composition consisting of 0.04-0.15 mass % C, 10.0-20.0 mass % Cr, 0.5-4.0 mass % Ni and the balance being Fe except inevitable impurities,
• a transformed structure composed of 20-85 vol. % martensite grains and the balance being ferrite grains with prior austenite grains controlled to 10 μm or less in size, and
• hardness of HV 300 or more. cm 2. The dual-phase stainless steel strip defined by claim 1, wherein the chemical composition further contains one or more of Si up to 2.0 mass %, Mn up to 2.0 mass %, not more than 0.050 mass % of P, not more than 0.020 mass % of S, 0-0.10 mass % of Al, 0-0.10 mass % of N, 0-1.0 mass % of Mo, 0-2.0 mass % of Cu, 0.01-0.50 mass % of Ti, 0.01-0.50 mass % of Nb, 0.01-0.30 mass % of V, 0.01-0.30 mass % of Zr, 0.0010-0.0100 mass % of B, 0-0.02 mass % of Y, 0-0.05 mass % of Ca. and 0-0.1 mass % of REM (rare earth metals). cm 3. The dual-phase stainless steel strip defined by claim 1 or 2, wherein an expansion rate during martensitic transformation of austenite is controlled to 9% or less in average.