High-Carbon Martensitic Stainless Steel and Production Method Therefor

Abstract

The present invention relates to a production method for high-carbon martensitic stainless steel as used in razorblades, knives and the like, which contains, as percentages by weight, 0.40 to 0.80% carbon and 11 to 16% chromium as main components. Provided is a production method for high-carbon martensitic stainless steel in a strip-casting device, wherein a stainless-steel thin sheet is cast by supplying a stainless molten steel containing, as percentages by weight, 0.40 to 0.80% carbon and from 11 to 16% chromium to a molten steel pool from a tundish via a nozzle, and the cast stainless-steel thin sheet is made into a hot-rolled annealed strip using in-line rollers to a rolling reduction of 5 to 40% immediately just after the casting so that the size of primary carbides within the microstructure of the hot-rolled annealed strip is 10 μm or less, and also provided is martensitic stainless steel produced by means of the production method. By reducing the size of the primary carbides formed in the cast structure and the hot-rolled sheet to 10 μm or less, the present invention produces high-carbon martensitic stainless steel having outstanding blade-end quality for use in cutting implements.

Description

TECHNICAL FIELD[0001]An aspect of the present invention relates to a high-carbon martensitic stainless steel and a production method therefor, and more particularly, to a high-carbon martensitic stainless steel and a production method therefor, which decreases the size of primary carbides by producing the high-carbon martensitic stainless steel, which contains, by percentages by weight, 0.4 to 0.8% carbon and 11 to 16% chromium, using a strip-casting process.BACKGROUND ART[0002]In general, a high-carbon martensitic stainless steel containing, as percentages by weight, more than 0.40% carbon has excellent corrosion resistance, hardness and abrasion resistance, and thus is used for razors, knives and the like. When a razor produced using the high-carbon martensitic stainless steel is used, the razor comes in contact with moisture in a shaving process.[0003]Since the razor is kept under a humid atmosphere, its corrosion resistance is required. Such an atmosphere is very severe when a h...

AI Technical Summary

Benefits of technology

[0025]As described above, according to the present invention, it is possible to apply a strip-casting method for directly producing a hot-rolled coil from a molten steel produced through a steelmaking process. Since the strip-casting method can remarkably decrease the size of primary carbides formed in a solidified structure, the strip-casting method can be usefully applied to the production of a high-quality razor. Particularly, since the hot-rolled coil is directly produced from the molten steel, the production process of the hot-rolled coil is simpler than the conventional ingot-casting method. Thus, it is possible to improve the quality of a razor and to considerably reduce production cost.

Problems solved by technology

Such an atmosphere is very severe when a high-carbon steel is used, and therefore, a martensitic stainless steel containing, as percentages by weight, about 13% chromium, is frequently used.

However, the content of carbon increases, the primary carbides are coarsely formed during the solidification process, and therefore, it is difficult to produce a high-quality razor.

Particularly, serious segregation occurs in an ingot-casting method generally used to produce a material for razor, and therefore, primary carbides are coarsely formed.

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