SU1148889A1 - Steel - Google Patents

Description

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I; D I The invention relates to ferrous metallurgy, in particular to steelmaking production, and can be used, for example, in the production of hot rolled sheet used for frame parts of heavy trucks. Famous steel 1 mark 15P) T, soda ryascha, ma s.%: Carbon0.11-0.16 Manganese1.0-1.4 Silicon0.15-0.35 Phosphorus 0.035 Sulfur 0.030 Titanium0.08-0.14 Aluminum0, 02-0.08 Iron. Remaining The disadvantage of this steel is low ductility characteristics () with the following strength characteristics: yield strength of 40 kg / mm, tensile strength 6b 50 kg / mm. Known steel containing, in May.%: Carbon 0.1-0.2 Manganese 0.6-2.5 Silicon 0.15-0.7 Copper0.1-0.5 Chromium 0.7-1.5 Molybdenum 0.15-0.4 Nickel 0.05-0.3 Vanadium 0.01-0.12 Zirconium 0.001-0.1 Aluminum 0.01-0.1 Iron Others This steel does not have sufficiently high mechanical properties (after improvement, 83 kg / mm; & 77.5 kg / mm2, cG 24%). The current level of engineering, in particular the automotive industry, requires the creation of new steel grades with higher plastic properties with an adequate stock of strength properties. In order to obtain a more durable, on a row with good formability, hot rolled sheet, low alloy 22G2YT steel with a higher carbon content, additionally alloyed with manganese and titium, is used. Closest to the proposed software, the content of alloying elements and the achievable hardening effect is steel 3, containing ftac. %: Carbon 0.19-0.26 Manganese t.3-1.7 Silicon 0.3-0.5 Sulfur 0.035 Phosphorus 0.030 Titanium 0.12-0.18 Aluminum 0.02-0.08 Iron Rest Disadvantages of the Known steels are a high content in the composition of the deficient elements of manganese and titanium, contamination by non-metallic inclusions such as titanium sulfides, aluminum oxides, which lower the strength characteristics of steel. Increased manganese content with a higher carbon content reduces ductility and increases structural heterogeneity. The purpose of the invention is to increase the strength and plastic properties. The goal is achieved by the fact that boron, barium, calcium and rare-earth metals are added to steel containing carbon, manganese, silicon and iron in the following ratio, wt.%: Carbon 0.15-0.20 Manganese 0.20-0-0, 50 Silicon 0.70-1.50 Bor0.001-0.01 Barium0,0005-0.005 Calcium0.001-0.025 RZM0.10-0.20 IronOtherly The introduction of boron in the steel in an amount of 0.001-0.01 wt.% Provides an increase strength and reduces the manganese content from 1 to 0.2-0.5%, and also exclude titanium from the steel composition. The content of m-arganese, 0.200, 50 wt.% With the introduction of boron in steel turned out to be optimal, with a content below 0.20 wt.%, The strength characteristics of the steel decrease (Table 2, smelting 5), and with a content above 0.50 wt. the strength of the steel is increased, but the plastic CBOPs are deteriorated (Table 2, melting 4). For silicon, the optimum content is 0.7-1.5 wt.%. The content below 0.7 wt.% Does not give the desired effect of hardening the ferritic matrix (Table 2, smelting 5), and the content of Bbmie 1.5 wt.% Leads to a significant decrease in ductility (Table 2, smelting 4). 31 The introduction of barium in the composition of the steel in the range of 0.0005-0.005 wt.%, Calcium in the range of 0.001-0.025 wt.% And REM in the amount of 0.10-0.20 wt.% Makes it possible to reduce the contamination of steel to nonmetallic inclusions. m, significantly improve the quality over the bone of the ingot steel, as well as improve the ductility. Steel is smelted in a 100 kg induction furnace. In this case, three compositions of the proposed steel and the known one are melted, two melts of the base composition and two melts with the limiting content of the components. The chemical composition of the experimental heats is presented in Table. 1. Ingots are hot forged, then, after heating to 1250 ° C, they are rolled into 8 mm thick strips in a laboratory mill (duo 400). The end temperature of the burnout is 900-930 ° C. Then heat treatment is performed (normalization is 950 ° C). 9 "Mechanical testing and experimental steels are manufactured according to GOST 1497-73 on samples manufactured in C (X according to the specification for this GOST. The result of the mechanical tests is given in Table 2. After the improvement, the steel has the following properties: be" 86-90 kg / mm; & f 79- 82 kg / mm; if 24.5-28%. The obtained data show that the steel of the proposed composition has strength and plastic properties above the steel of a known and basic composition. The calculation of the economic efficiency of the proposed technical solution richesLim method of pricing of new products, showed that one ton of steel proposed soe- Thane cheaper by 1-2 rubles in comparison with the equivalent amount of steel known composition.

Table 2

Strength 4,

Melting kg / mm Steel of the proposed composition 860 -790 880800, 900820 Steel with a limiting content of com 7357 4537.5 Steel of known composition 5946 6349.5 6954 Steel of basic composition 5142 5444

Relative.

Yield point (0, -, elongation (,% kg / mm iO 32 23 22 18 18 23

Claims (1)

- STEEL containing carbon, manganese, silicon and iron, which is characterized in that, in order to: increase strength and plastic properties, it additionally contains boron, barium, calcium and rare-earth metals in the following ratio of components, wt.%: Carbon 0.15-0.20 Manganese 0.20-0.50 Silicon 0.70-1.50 Boron 0.001-0.01 Calcium 0.00140.025 Barium 0.0005-0.005 REM 0.10-0.20 Iron Rest