RU2307198C1 - High-speed steel - Google Patents

Abstract

FIELD: ferrous metallurgy; composition of steels used for manufacture of cutting tools working at high cutting speeds under rugged conditions.

SUBSTANCE: proposed steel contains the following components, mass-%: carbon, 0.5-0.9; silicon, 0.05-0.1; manganese, 0.1-0.2; chromium, 5.0-6.0; tungsten, 3.0-4.0; molybdenum, 5.0-6.0; vanadium, 1.0-2.0; nickel, 4.0-5.0; cobalt, 2.5-3.5; titanium, 0.4-0.6; strontium, 0.001-0.002; the remainder being iron.

EFFECT: increased impact strength.

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Description

The invention relates to the field of ferrous metallurgy, in particular to compositions of steels used for the manufacture of a variety of cutting tools operating at high cutting speeds, in severe conditions.

Known high-speed steel containing, wt.%: Carbon 0.82-0.89; silicon 0.27-0.4; manganese 0.2-0.28; chrome 3.7-4.3; tungsten 5.6-6.2; molybdenum 5.1-5.7; vanadium 1.81-2.05; nickel 0.18-0.26; strontium 0.03-0.08; iron the rest [1].

Known high-speed steel, containing, wt.%: Carbon 0.35-1.5; silicon 0.1-2.0; manganese 0.1-1.5; chrome 2.0-10.0; tungsten 0.5-23.0; molybdenum 0.5-12.0; vanadium 0.5-5.0; nickel 0.25-2.0; cobalt 1.0-20.0; titanium ≤2.0; REM 0.005-60.0; iron - the rest [2].

The objective of the invention is to increase the toughness of steel.

The technical result is achieved by the fact that high-speed steel containing carbon, silicon, manganese, chromium, tungsten, molybdenum, vanadium, nickel, cobalt, titanium, iron, additionally contains strontium in the following ratio of components, wt.%: Carbon 0.5-0 ,9; silicon 0.05-0.1; manganese 0.1-0.2; chrome 5.0-6.0; tungsten 3.0-4.0; molybdenum 5.0-6.0; vanadium 1.0-2.0; nickel 4.0-5.0; cobalt 2.5-3.5; titanium 0.4-0.6; strontium 0.001-0.002; iron is the rest.

The table shows the compositions of high speed steel.

Impact strength of steel will be ~ 450 kJ / m ² for all the compositions listed in the table.

The increase in toughness of high-speed steel is due to the complex effect of its constituent components. Chromium, molybdenum, tungsten, and vanadium form carbides that are soluble in steel upon heating, but are hardly released from solution. Molybdenum in combination with tungsten sharply increase the resistance of steel to plastic deformation. Titanium forms stable carbides that are not soluble in austenite. Chrome and manganese increase the hardness of steel, but manganese gives the steel thermal brittleness, which is eliminated by the introduction of nickel. Nickel combined with cobalt reduces the tendency of steel to crack. Strontium contributes to obtaining a fine-grained structure.

Table Components Composition, wt.%: one 2 3 Carbon 0.5 0.7 0.9 Silicon 0.1 0,07 0.05 Manganese 0.1 0.15 0.2 Chromium 6.0 5.5 5,0 Tungsten 3.0 3,5 4.0 Molybdenum 5,0 5.5 6.0 Vanadium 2.0 1,5 1,0 Nickel 4.0 4,5 5,0 Cobalt 3,5 3.0 2.5 Titanium 0.4 0.5 0.6 Strontium 0.001 0.0015 0.002 Iron rest rest rest

Steel can be smelted in electric furnaces. Heating of high-speed steel for hardening is carried out to a temperature of 1280-1300 ° C for the most complete dissolution of carbides. After hardening, the steel is subjected to tempering at a temperature of 560-580 ° C. Steel after hardening and tempering may be subject to cold working.

Information sources

1. SU 1583462, C22C 38/46, 1990.

2. JP 57143471, C22C 38/48, 1982.

Claims (1)

High-speed steel containing carbon, silicon, manganese, chromium, tungsten, molybdenum, vanadium, nickel, cobalt, titanium and iron, characterized in that it additionally contains strontium in the following ratio, wt.%: carbon 0.5-0.9 silicon 0.05-0.1 manganese 0.1-0.2 chromium 5.0-6.0 tungsten 3.0-4.0 molybdenum 5.0-6.0 vanadium 1.0-2.0 nickel 4.0-5.0 cobalt 2.5-3.5 titanium 0.4-0.6 strontium 0.001-0.002 iron rest