Martensitic stainless steel, method for the production of a semi-finished product from said steel, and cutting tool produced from the semi-finished product

Abstract

The invention relates to a martensitic stainless steel characterized in that its composition consists of, by weight percent: 0.10%<=C<=0.45%; traces<=Mn<=1.0%; traces<=Si<=1.0%; traces<=S<=0.01 %; traces<=P<=0.04%; 15.0%<=Cr<=18.0%; traces<=Ni<=0.50%; traces<=Mo<=0.50%; traces<=Cu<=0.50%; traces<=V<=0.50%; traces<=Nb<=0.03%; traces<=Ti<=0.03%; traces<=Zr<=0.03%; traces<=Al<=0.010%; traces<=O<=0.0080%; traces<=Pb<=0.02%; traces<=Bi<=0.02%; traces<=Sn<=0.02%; 0.10%<=N<=0.20%; C+N>=0.25%; Cr+16N-5C>=16.0%; preferably 17Cr+500C+500N<=570%; the remainder being iron and impurities resulting from production. The invention also relates to a method for the production of a semi-finished product from the aforementioned martensitic stainless steel, and a cutting tool produced from said semi-finished product.

Description

technical field [0001] The invention relates to a martensitic stainless steel. This steel is mainly used in the manufacture of cutting tools, especially knives, such as scalpels, scissors blades or table knife blades or household food processors. Background technique [0002] Steel used for knives must have high corrosion resistance, polishability and hardness. [0003] Martensitic stainless steels currently used for the production of cutting tool inserts, such as steels of grades EN 1.4021, EN 1.4028 and EN 1.4034, have Cr content levels less than or equal to 14 wt% or 14.5 wt% and variable C content levels, i.e. , EN 1.4021 is 0.16% to 0.25%, EN 1.4028 is 0.26% to 0.35%, and EN 1.4034 is 0.43% to 0.50%. The hardness level of the steel mainly depends on this C content level. [0004] When pursuing better corrosion resistance, EN 1.4419 can be used, which has 0.36~0.42%C, 13.0~14.5%Cr and 0.60~1.00%Mo. [0005] During the manufacturing process, these steels are usually m...

AI Technical Summary

Problems solved by technology

Corrosion resistance is also insufficient because the level of Cr content in the matrix is ​​not high enough, especially part of Cr is trapped in undissolved carbides

In addition, the cutting edge of the insert is often subject to crevice corrosion due to cracks in most of the carbides that appear at the end of solidification during continuous casting

[0011] EN 1.4021 and 1.4028, which contain less C, are less hard and do not have sufficient corrosion resistance due to too low levels of Cr

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