Martensitic stainless steel and a production method therefor

Abstract

The present invention relates to a martensitic stainless steel as used in tableware, knives, scissors and the like, which contains, as percentages by weight, from 0.10 to 0.50% of carbon and from 11 to 16% of chromium, and relates to a production method therefor; and the invention relates to a production method for mid-carbon martensitic stainless steel in a strip-casting device comprising a pair of rollers which rotate in opposite directions, an edge dam which is provided so as to form a molten steel pool at both side surfaces, and a meniscus shield for supplying inert nitrogen gas to the upper surface of the molten steel pool, wherein steel for stainless steel containing, as percentages by weight, from 1.10 to 0.50% of carbon and from 11 to 16% of chromium is supplied from a tundish, via a nozzle to the molten steel pool in such a way that a stainless-steel thin sheet is cast,; and the cast stainless-steel thin sheet is made into hot-rolled annealed strips using in-line rollers to a rolling reduction of from 5 to 40%, and relates to martensitic stainless steel produced by means of the production method. The present invention suppresses lamination defects by reducing carbide centre segregation and makes it possible to obtain martensitic stainless steel with little difference in hardness between carbide-segregated zones and non-segregated zones and hence with uniform hardness overall.

Description

Technical field [0001] The invention relates to a martensitic stainless steel and a manufacturing method thereof, in particular to the use of a thin strip continuous casting method to manufacture medium-carbon martensitic stainless steel containing 0.10-0.50% carbon and 11-16% chromium to reduce the laminated structure, Medium-carbon martensitic stainless steel with uniform hardness and its manufacturing method. Background technique [0002] Generally, martensitic stainless steel is manufactured by the following manufacturing process. That is, a continuous cast sheet is manufactured by casting molten steel and then reheated and hot rolled. In the state of hot rolling, the structure of the steel is mixed with martensite phase, tempered martensite phase, and retained austenite. The state exists. This hot-rolled coil undergoes a box furnace annealing process for hot-rolled sheet annealing, and is transformed into ferrite and carbides to be softened. In order to remove the formed r...

AI Technical Summary

Problems solved by technology

[0004] In the case of producing the existing 200-250mm plate, in order to minimize the center segregation, the casting speed is reduced to 70-80% of the usual continuous casting process, but the continuous casting production efficiency may be significantly reduced. question

In addition, in order to solidify the coarse carbides formed at the center during casting, the annealing temperature and holding time of batch annealing after hot rolling are too long, which leads to a sharp drop in production efficiency.

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