SU1617018A1 - Method of producing cold-rolled low-alloy plate steel - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular to methods for processing hot rolled strip of low carbon steels in the manufacture of cold rolled sheets for deep drawing. The aim of the invention is to improve the homogeneity of the microstructure of cold-rolled steel and the level of mechanical properties. After etching, the strip is cold rolled to a strip with a thickness of 2.0-0.5 mm with variation of the total degree of deformation in the range of ε _in -ε _N , ε _in = [82-K ₁ (T _cm -500) ±%, ε _N = [50 + К ₂ (T _cm -500) ± 2%, where ε _N is the lower limit of the degree of total deformation, ε _in - the limit of the degree of total deformation is true. K ₁ and K ₂ dimensional coefficients,% ° С, equal respectively to 0.028 and 0.0114. The application of the method makes it possible to increase the homogeneity of the structure: the radio grain size parameter D _max / D _{or op} is the ratio of the maximum grain size to the average for the invention and the protopite was 1.56 and 1.96 respectively. 1 tab.

Description

The invention relates to black iron and steel, in particular to methods for treating hot rolled low carbon steel strips in the production of cold rolled .UICTOB for deep-drawing.

The purpose of the invention is a higher uniformity of the cold rolled steel and the level of mechanical property.

PRI mme RO Method tested in the production of shzou1: cold-rolled cold-rolled steel for cold extrusion on steel grade 08KI under the conditions of CarMCo

Processing by the proposed method included the following operations

Hot rolling slabs on NShPS 1700 per strip 2.5–4.5 mm thick (temlera 7 Typia end of rolling was in the range of 840–900 o, coiling temperature varied in the range of 500–675 ° C)

Etching

Cold rolling on a 5-stand mill 1700 per strip with a thickness of 2.0-0.5 mm with variation of the total steCX5

KI category VG "Testing with deformation wire in the range of 42-85%"

Heat treatment in pack ovens at the final annealing temperature; 620 - for cold-rolled strips with a thickness of less than 1.2 mm; 650-675 ° С - hb L1,2 mmo

Training annealed strips with a degree of deformation of 055-0.9%

Measurement of mechanical properties (J, IE according to GOST 9045-80 for steel category VG

The specific parameters of the implementation of the proposed method in comparison with the known are given in the table

As can be seen from the table, the application of the proposed method for the production of cold-rolled low-carbon sheet steel allows, in comparison with the known method, to improve the uniformity of the structure of cold-rolled strip and the level of mechanical properties. Thus, for batch No. 2 (cMc table), the grain-difference parameter grain to average) for the proposed and known methods were respectively 1.56 and 1.96. The spread of the values of mechanical properties (G jp. O) the average level was also: for 28-37 26-41

. . . 2 "-J /, .D- I (Jg kg / mm -, -j and -3276

but for

I

29-31 27-30 29.4

It is convenient to compare the level of the depth values of the extruded hole, which characterizes the ability of steel to deep-draw, for a constant final

five

five

0

thirty

35

Which band (sms batch 5 in the table): for the proposed method IE, it is 10.46 mm; for the known method - 10.16 pts. Finally, the processing in accordance with the proposed method resulted in 5 -6% „

Claims (1)

Invention Formula Method for the production of cold-rolled low carbon steel sheet, including hot rolling, cooling from a rolling end temperature of 840 - 900 C to a coiling temperature of 675-500 C, pickling, cold rolling, heat treatment and training, By the fact that, in order to improve the homogeneity of the microstructure of cold-rolled steel and the level of mechanical properties, cold rolling is carried out with a total degree of deformation within g-6 based on the relation: e, -50 +, - 500) i2%; (82 - K, (t - 500) D ± 1%, where is the lower limit of the total strain; fg is the upper limit of the total strain;  size coefficients,%, C, equal, respectively, 0.028 and Os1l4; coiling temperature. In the numerator are factual nachsggil IE, and z.chmsiltsls - according to GOST 9045-80. Note, Values of O bp f according to GOST 9045-80, respectively 26-37 kg / mm and 281 for h, - 0.5-1.5 mm; 29L - days “1.5-2 nm.