SU1458420A1 - Die steel - Google Patents

Abstract

The invention relates to metallurgy, in particular to high strength heat resistant die steels. forming tool manufactured by hot plastic deformation and subjected to nitriding. The purpose of the invention is to increase the ultimate strength, technological plasticity, fatigue strength at 600 ° C after nitriding. Steel additionally contains boron in the following ratio of components, wt%: carbon 0.34-0.46; silicon 0.15-0.4; manganese 0.15-0.4; chromium 2-2.8; tungsten 2.6-3.4; molybdenum 0.8-1.5; vanadium 0.3-0.8; titanium 0.01-0.06; aluminum 0.06-0.45; boron 0.0005-0.002; iron balance, at ratios: vanadium / titanium 5-80; Aln 1ini / titanium 1-45, with more and less. the values of the ratio of vanadium and titanium correspond to larger and smaller values of the ratio of aluminum and titanium, respectively. The use of steel will increase the durability of the tool under cyclic loads. 2 tab. ID ate With

Description

The invention relates to metallurgy, in particular, to high-strength heat-resistant die steel for forming tools, produced by hot plastic deformation and subjected to nitriding, and can be used in metallurgical and machine-building industries.

The purpose of the invention is to increase the ultimate strength, technological strength, fatigue strength at 600 ° C after the nitriding of steel. The chemical composition of the experimental heats is given in Table 1. Steel is smelted

iron based direct reduction.

Steel properties were determined on heat-treated samples according to the following mode: quenching from 1140 ° С to oil, tempering at 1.5 h and second time tempering at 580 ° С 1.5 h. Nitriding according to the following mode: 520 ° С, 10 h degree ammonia dissociation 25-30%, 620 ° C, 0.5 hours without ammonia and 4.5 hours without ammonia.

The tensile strength was determined on standard shortened specimens.

Fatigue strength was evaluated by the limit of fineness (6.,) with

four:

: l

thirty

four

N0

about

tests on the machine MUI-6000 with a base of N 10 cyclo in

 Technological plasticity was determined by twisting the ruptured specimens at 1100 ° C by the number of revolutions before failure.

The test results are shown in Table 2.

The proposed steel has the best complex of properties that have a decisive influence on the tool durability under cyclic loads, and, moreover, it is better subjected to pressure treatment in hot pressing.

From the proposed and well-known steels, dies were made for pressing a U-shaped profile. The stability of nitrated matrices of the proposed steel was 42 m (7 compacts 6 m each), | - while 30 m (5 compacts) each of the famous steel .

Claims (1)

Invention Formula Die-cutting steel, predominantly for nitriding, containing carbon 58420 silicon, manganese, chromium, tungsten, molybdenum, vanadium, titanium, aluminum, iron, characterized in that, in order to increase the tensile strength, technological plasticity, fatigue strength after nitriding, it additionally contains boron in the following ratio of components, %: ten 15 20 25 Carbon0.34-0.46 Silicon0.15-0.40 Manganese 0.15-0.40 Chrome 2.00-2.80 Tungsten 2.60-3.40 Molybdenum 0.80-1.50 Vanadium 0.30-0.80 Titan0,01-0,06 Aluminum 0.06-0.45 Bor0,0005-0,002 IronErest with the proviso that the ratios j are vanadium / titanium 5-80; aluminum / / titanium 1-45, with a larger and a smaller value of the ratio of vanadium to titanium corresponds to a larger and smaller value of the ratio of aluminum to titanium, respectively The content of elements, wt.% Note. The content of sulfur and phosphorus in the steel of 1-3 is no more than 0.012%, in steel 4 it contains cejw 0.0241, phosphorus 0.0261, the rest is iron; -3 steel smelted on the basis of direct reduced iron; steel 4 - on steel scrap Table 1 Table. 2