High-dimension stable corrosion-resistant martensite steel and preparation method of steel structural material

The invention discloses a high-dimension stable corrosion-resistant martensite steel and a preparation method of a steel structural material. The martensite steel comprises the following chemical components of: C being less than or equal to 0.10, Cr being 14.0-15.5, Ni being 4.2-6.0, Cu being 2.0-3.5, Nb being 0.2-0.40, Mn being less than or equal to 0.7, Mo being 0.3-0.8, Si being less than or equal to 1.0, P being less than or equal to 0.02, S being less than or equal to 0.015, and the balance being Fe. The preparation method of the above steel structural material contains the following steps of: 1) weighing each component according to the weight percentage of each component; 2) carrying out vacuum induction melting; 3) casting and remelting electrode bars; 4) remelting electroslag to obtain steel ingots; 5) carrying out homogenization heat treatment; 6) forging wire rod and board strip blank materials; and 7) carrying out finishing, flaw detection and cold machining on the wire rod and board strip blank materials. By the formation of high-toughness low carbon lath-shaped martensite and enhanced means of supplementing molybdenum, copper and other alloy elements, the martensite steel with high strength and toughness, high corrosion resistance and wear resistance is obtained. The preparation method meets requirements such as strong corrosion resistance, excellent abrasion resistance, good machinery processing property, high dimension stability and ferromagnetism.