Martensitic stainless steel and method for manufacturing same

Abstract

The present invention relates to a martensitic stainless steel for use in knives such as a kitchen knife, and to a method for manufacturing same. More particularly, the present invention provides a martensitic stainless steel manufactured by strip casting and a method for manufacturing the martensitic stainless steel, in which the components of the steel are controlled such that C is 0.4 to 0.5%, N is 0.1 to 0.2%, Cr is 13 to 15%, Si is 0.1 to 1.0%, Mn is 0.1 to 1.0%, Ni exceeds 0 and is lower than 1.0%, C+N is 0.5% or higher and N / C is 0.2% or higher, wherein the remainder comprises Fe and other inevitable impurities. The size of the residual carbide of the martensitic stainless steel is 10 [mu]m or lower and the hardness of the residual carbide is 55HRC or higher. The martensitic stainless steel of the present invention is manufactured by strip casting in such a manner that the length of the residual carbide remaining after strengthening heat treatment becomes 10 [mu]m or lower when performing the strengthening heat treatment on the annealed hot -rolled steel strip having a thickness of 1mm or higher manufactured by strip casting. Thus, a martensitic stainless steel to be used in knives such as a kitchen knife having excellent blade tip quality and superior hardness and corrosion-resistance can be obtained.

Description

technical field [0001] The present invention relates to a martensitic stainless steel and a manufacturing method thereof, and more particularly to a martensitic stainless steel to which a rapid cooling casting method is applied for high-grade kitchen knives and a manufacturing method thereof. Background technique [0002] Martensitic stainless steel is essentially a steel composed of iron (Fe)-chromium (Cr)-carbon (C) as the main component. 1% carbon. For such martensitic stainless steels, alloy manufacturers apply a batch annealing process to produce hot-rolled annealed sheets composed of ferrite phase and Cr carbonitrides, followed by pickling of the hot-rolled annealed sheets, and then It is cold-rolled to meet the thickness required by the final customer and supplied. Next, the final customer applies an intensive heat treatment process to the stainless steel, thereby transforming the soft material composed of ferrite and carbide into a high-hardness martensitic structu...

AI Technical Summary

Problems solved by technology

However, even with the rapid cooling casting method, coarse carbides condense at the crystal grain boundaries in the final strengthening heat-treated structure and may still appear unsuitable for use as a knife.

Images