Martensitic stainless steel, method for making parts from said steel and parts thus made

Abstract

The invention relates to a martensitic stainless steel characterised in that it comprises in weight percent: - 0.22% <= C <= 0.32% - 0.05% <= N <= 0.15%, with 0.33% <= C+N <= 0.43% - 10% <= Cr <= 12.4% - 0.10% <= V <= 0.40% - 0.10% <= Mo <= 1.0% - traces <= Ni <= 1.0% - traces <= Mn <= 1.0% - traces <= Si <= 1.0% - traces <= W <= 1.0% - traces <= Co <= 1.0% - traces <= Cu <= 1.0% - traces <= Ti <= 0.010% - traces <= Nb <= 0.050% - traces <= Al <= 0.050% - traces <= S <= 0.020% - traces <= O <= 0.0040% - traces <= P <= 0.03% - traces <= B <= 0.0050% - traces <= Ca <= 0.020% - traces <= Se <= 0.010% - traces <= La <= 0.040% - traces <= Ce <= 0.040%, the balance consisting of iron and impurities resulting from the production. The invention also relates to a method for producing a part made of such a steel and to the part thus obtained, as a mould element for the production of plastic articles.

Description

technical field [0001] The present invention relates to steelmaking, and more particularly to martensitic stainless steels for use, for example, in the production of molds for the production of plastic materials by injection moulding. Background technique [0002] In order to produce molds for material injection molding, industrially use a chromium content of 12% to 15% (weight percentage, all contents indicated in the rest of this article are also weight percentages), a silicon content of less than 1%, and a manganese content of less than 1%. , AISI 420 family stainless steel with a carbon content of 0.16% to 0.45% and a nitrogen content naturally introduced due to production operations usually up to 0.03%. Generally, the vanadium content does not exceed 0.1% and is the result of simple fusion of the raw materials. Likewise, molybdenum is contained as a result of raw material fusion and does not exceed 0.2% molybdenum unless 0.2% to 1.0% molybdenum is added for corrosion r...

AI Technical Summary

Problems solved by technology

The high temperature tempering operation decomposes austenite and relieves residual stresses, but reduces strength and corrosion resistance

[0020] There is also a cost issue with these steels as they require high alloying element contents which should be able to be reduced without compromising the desired properties

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