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Chromium ferritic stainless steel in precipitation strengthening, strip steel and making method thereof

A technology of precipitation strengthening and manufacturing method, which is applied in the direction of manufacturing tools, metal rolling, temperature control, etc., can solve the problems of corrosion, cost increase, formability, weldability and tensile strength not as good as 304 stainless steel, etc., to reduce production cost, Effect of improving yield strength and good ductility

Inactive Publication Date: 2008-12-24
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The price of 400 series stainless steel is low, the thermal expansion coefficient is low, and the resistance to chloride stress is worse than that of 300 series. 400 series stainless steel is low, and it will be corroded when used in an environment with severe chemical atmosphere, so its application is limited. However, if a trace amount of niobium, titanium, copper or aluminum is added to 400 series stainless steel, its deep drawing performance can be improved. Weldability, corrosion resistance in atmospheric fresh water and oxidizing media (such as nitric acid)
[0007] At present, the microstructure of Cr17 ferritic stainless steel produced at home and abroad is mainly ferrite. The corrosion resistance and mechanical strength of the steel are improved by adding a small amount of trace alloying elements titanium and niobium. Some steel types also add molybdenum. However, due to the rising price of molybdenum in recent years, the addition of molybdenum will increase the cost of steel

Method used

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  • Chromium ferritic stainless steel in precipitation strengthening, strip steel and making method thereof
  • Chromium ferritic stainless steel in precipitation strengthening, strip steel and making method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Stainless steel is smelted by electric furnace and oxygen-argon decarburization converter (AOD) according to the chemical composition shown in Table 3, and the molten steel after smelting is poured into a slab on a continuous casting machine. The crystal ratio reaches 36%. After the slab is cut into the required length, the slab is cooled to room temperature, and the surface defects of the slab are removed with a grinding wheel, and then transferred to a heating furnace to be heated to 1055°C. After the high-temperature iron oxide surface is removed by high-pressure water, the The rolling mill is rolled into strip steel in multiple passes, and coiled to form a steel coil. The final rolling temperature is 823°C, the coiling temperature is 680±30°C, and air-cooled to room temperature. Then the above-mentioned hot-rolled steel coils are first annealed in a bell annealing furnace at an annealing temperature of 845°C, kept for more than 12 hours, slowly cooled at a cooling ra...

Embodiment 2

[0041] The implementation method is the same as in Example 1, wherein the equiaxed crystal ratio is 39%, the slab heating temperature is 1070°C, the strip finish rolling temperature is 840°C, the hot-rolled coil annealing temperature is 860°C, and the hot-rolled coil annealing cooling rate is 40°C / S, and the annealing temperature of cold-rolled strip steel is 870°C.

Embodiment 3

[0043]The embodiment is the same as in Example 1, wherein the proportion of equiaxed grains is 38%, the slab heating temperature is 1090°C, the strip finish rolling temperature is 850°C, the hot-rolled coil annealing temperature is 870°C, and the hot-rolled coil annealing cooling rate is 30°C / S, and the annealing temperature of cold-rolled strip steel is 860°C.

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Abstract

The invention provides a precipitated and strengthened medium chromium ferritic stainless steel, a strip steel manufactured by a steel grade and a method for manufacturing the strip steel. The precipitated and strengthened medium chromium ferritic stainless steel consists of the following chemical compositions: less than or equal to 0.04 weight percent of C, 0.2 to 0.6 weight percent of Si, 0.25 to 0.6 weight percent of Mn, less than or equal to 0.02 weight percent of S, less than or equal to 0.03 weight percent of P, 16.0 to 18.0 weight percent of Cr, 1.2 to 1.6 weight percent of Cu, less than or equal to 0.02 weight percent of N, the balance being Fe and inevitable impurities. Electromagnetic stirring is adopted to carry out smelting and casting to the steel grade; and a proper hot rolling temperature, a crimping temperature, a cold rolling reduction and other process conditions are controlled, thereby manufacturing the precipitated and strengthened medium chromium ferritic stainless steel. The ferritic stainless strip steel has high yielding strength and tensile strength and good plastic extendibility and meets the requirement of deformation machining.

Description

technical field [0001] The invention relates to stainless steel materials, in particular, the invention relates to a precipitation-strengthened medium-chromium-ferritic stainless steel, a strip made of the steel and a method for manufacturing the strip. Background technique [0002] In the entire stainless steel consumption market, 300 series stainless steel accounts for more than 70%, of which ferrite accounts for about 20%. Series stainless steels are less affected in this regard because they do not contain nickel. The traditional 400 series represents steel grades including ferritic 430 (17% Cr) and martensitic 410, 420 (13% Cr), among which 430 is used in the largest amount. The price of 400 series stainless steel is low, the thermal expansion coefficient is low, and the resistance to chloride stress is worse than that of 300 series. 400 series stainless steel is low, and it will be corroded when used in an environment with severe chemical atmosphere, so its application...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/20C21C7/068B22D11/115B21B37/74B21D5/00C21D8/00C21D1/26B21B37/16
Inventor 李步明余海峰戚国平
Owner BAOSHAN IRON & STEEL CO LTD
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