Martensitic stainless steel and manufacturing method thereof

Abstract

The invention discloses martensitic stainless steel, which comprises the following components in percentage by mass: 0.10-0.15 percent of carbon, 0.20-0.50 percent of silicon, 0.50-1.50 percent of manganese, 2.00-4.00 percent of nickel, 15.00-17.00 percent of chromium, 0.03-0.30 percent of molybdenum, 0.020-0.200 percent of nitrogen, 0.01-0.10 percent of rare earth, less than or equal to 0.25 percent of copper, less than or equal to 0.025 percent of sulfur, less than or equal to 0.040 percent of phosphorous and the balance of Fe and inevitable impurities. The martensitic stainless steel has strength and plasticity, high low-temperature impact ductility and corrosion resistance, and can be applied to a hydraulic cylinder shaft for manufacturing a ship. The invention also discloses a manufacturing method of the martensitic stainless steel.

Description

technical field [0001] The invention relates to martensitic stainless steel, in particular to the martensitic stainless steel which can be used to manufacture hydraulic cylinder shafts of ships, and has high strength plasticity, high and low temperature impact toughness and corrosion resistance. Background technique [0002] The ship's hydraulic system is the hub of the power transmission of the hull. It uses liquid as the working medium and uses the pressure energy of the liquid to realize a transmission mode of motion and power transmission. In recent years, with the development of large-scale and high-speed ships, higher requirements have been put forward for the comprehensive performance of ship steel (marine steel). According to the certification requirements of European classification societies (high standard requirements), the The comprehensive performance of such materials should reach: tensile strength (Rm) 800MPa, yield strength (Rp0.2) 600MPa, elongation (A) 15%, ...

AI Technical Summary

Problems solved by technology

[0005] Ni-free stainless steel (such as 17Cr16Ni2, 14Cr16Ni2 and X17CrNi16-2) has a lower manufacturing cost (low Ni, or Ni-free), which can meet the needs of ordinary ocean transportation, but its low-temperature impact toughness is poor, only 10-20J (such as 17Cr16Ni2 -20 ℃ impact A kV -20℃ impact A for 10-15J, 14Cr16Ni2 and X17CrNi16-2 only kV Only 15-20J), which cannot meet the needs of marine transportation in low-temperature marine environments (the high standard certification requirements of the European Bureau of Shipping -20°C Shock A kV greater than 27J)

[0006] Ni-containing stainless steel (such as X4CrNiMo16-5-1) has better low-temperature impact (-20°C impact A kV It can reach more than 100J), which can meet the needs of marine transportation in low-temperature marine environments. However, the Ni content is as high as 5.0%-6.0%. Since Ni is a precious metal element, the cost of steel limits the popularization and application of this type of material

[0007] There are some patent applications related to high-toughness martensitic stainless steel, such as the high-toughness martensitic stainless steel disclosed in CN200710099335.3 and CN200310104844.2, but the content of Mo and Ti elements is relatively high, so the smelting cost is obviously too high

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