SU1423610A1 - Method of manufacturing steel strips - Google Patents

Abstract

The invention relates to rolling production and can be used in workshops for the production of cold rolled strip and sheet with high strength and ductility requirements. The purpose of the invention is to increase the strength and ductility of steel strips. After cold rolling, the strips are wound into a coil with a tension of 0.4-0.9 of the yield strength of the material and, in the wound State, are tempted at 370-440 ° C. 1 hp f-ly, 1 tab.

Description

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The invention relates to rolling production and can be used in workshops for the production of cold rolled strip and sheet with high requirements for strength and ductility.

The purpose of the invention is the behavior of the strength and plastic properties of steel strips.

In the cold rolling shop, containing a five-millite continuous mill 630 and single-stop bell-type furnaces for processing coils, produce strips of 65G steel of 0.7–1.2 mm thick and 250–465 mm wide after cold rolling. The relative rolling reduction is 45-50%. The tension of the bands during winding on the drum of the winder is adjusted from zero to 150 kN. After winding the strips into coils, they are vacated at 350-500 ° C.

After heat treatment, the metal is tested and the temporary tensile strength (C) and relative elongation (S) are determined.

In the cold rolling process, different levels of tension are set on different coils and tempering is carried out 5 by varying the heating temperature.

The results of the test bands are presented in the table.

The tension of the strip during rolling is set in kN, the specific tension (CJ) is determined as the ratio of the tension to the cross-sectional area of the strip, and the tension level (K) is defined as the ratio of the specific tension to the conditional limit of honor (G) to be wound . stripes.

Deviation from the proposed modes causes a decrease in strength (experiments 2 and 8), either leads to frequent strip stripes and the impossibility of winding it into a roll (test 4), or it is not possible to obtain the required plasticity of the strip (test 6).

Winding the strips into coils with a tension of 0 °, 68-0.85 yield strength (a known method) allows to reduce

crescent bands and their flatness. However, by itself, this method of producing steel strips does not provide a combination of high strength and ductility properties, primarily in the production of strips of medium and high carbon steel grades. After cold rolling and winding the strips into a coil with a tension of 0.6-0.9, the yield strength of a strip with a thickness of 0.1-1.2 mm made of 65G steel has a temporary resistance of razg ragau (CJg) within 800-900 MPa at relative elongation () 1-2%, i.e. the bands have low ductility and insufficient strength.

In the production of steel strips by the proposed method, i.e. winding with tension O, 4-0.9 of yield strength and subsequent heat treatment at 370-440 ° С, get bands with G 960-1020 MPa at 54 10-12%, i.e. with a combination of high ductility and strength. Bands with such properties allow replacing less durable and ductile strips with stronger and ductile ones with a smaller cross-sectional area and, thus, saving metal.

Claims (2)

1. A method of producing steel strips, mainly from medium to high carbon steels, including cold rolling the billet and winding the strips into coils with a given tension, characterized in that, in order to increase the strength and ductility properties of the steel strips, after winding the strips, they are spent - start at 370-440 ° С. 2. Method pop. 1, which differs from the fact that the tension of the strips during winding is carried out at voltages of 0.4-0.9 from the yield strength of the material after cold rolling. "" Frequent pistons when rolling. The ductility of the strip is low; an increase in the strip cross section is required.