SU1567649A1 - Method of producing semifinished product from high-carbon steels - Google Patents

Abstract

The invention relates to metallurgy and can be used in enterprises of the metallurgical industry in the manufacture of billets of high carbon steels. The purpose of the invention is to improve the quality of the workpiece and reduce the specific consumption of metal for rolling. The ingots of steel of grade 54 PP were heated by rolling to 850 ° C, kept at this temperature for 0.5 h and further heated to 1250 - 1270 ° C, and 2.5 hours before the end of heating, the ingots were turned around its axis. 180 °. After rolling ingots on the blooming, it was found that the use of the method allows to increase the yield by 0.9-1.2%, and the specific consumption of metal per rolling is reduced by 15-20 kg / ton. 1 tab.

Description

one

(21) 4449687 / 23-02

(22) 05.23.88

(46) 05.30.90. Bul Number 20

(71) West-Siberian Metallurgical Combine named after 50th Anniversary of the Great Oct. Br.

(72) V.G. Bukhteev, V.A.Saprykin, V.M.Golubev, I.S. Kuznetsov, S.V.Belikov, Yu.T.Rubtsov, V.V.Semakhin and S.S. Zhdanov

(53) 621.785.79 (088.8)

(56) USSR Copyright Certificate No. 1238820, cl. B 21 B 3/00, 1984.

USSR author's certificate 1315042, cl. B 21 B 3/00, 1986.

(54) METHOD OF MANUFACTURING PREPARATIONS OF HIGH-CARBON STEELS

(57) The invention relates to metallurgy and can be used in enterprises of the metallurgical industry in the manufacture of billets of high carbon steels. The purpose of the invention is to improve the quality of the workpiece and reduce the specific consumption of metal for rolling. The ingots of steel grade PP 54 are heated by rolling to 850 ° C, kept at this temperature for 0.5 hours, and further heating to I250-I270C takes place, and 2.5 hours before the end of heating, the ingots are rotated around its axis by 180 °. After the ingots were rolled on the blooming, it was found that the use of the method allows to increase the yield by 0.9-1.2%, and the specific metal consumption per rental is reduced by 15-20 kg / ton. 1 tab.

with s

(L

The invention relates to rolling production, in particular to the production of blanks from ingots of a large mass of high carbon steels.

The purpose of the invention is to improve the quality of the workpiece and reduce the specific consumption of metal for rolling.

The essence of the method is that at the beginning of heating, at isodes of 800-870 ° C, isothermal aging is carried out for 0.4-0.6 hours, and 2-3 hours before the end of heating, ingots are rotated around its axis by 180 °

In order to uniformly heat the ingot over the grains over the cross section and thereby ensure high ductility of the metal, the ingots are turned around

on its axis by 180 °, since the face of the ingot, which is near the wall of the heating well, is not heated, it enters the torch flame zone and is heated evenly. Rotation of ingots around its axis to a smaller or larger angle, for example 90 or 270 °, does not ensure uniform heating of the ingot surface due to the fact that the face of the ingot located near the wall of the well does not fall into the torch torch zone. Different temperatures of different metal layers, causing their different ductility, cause additional napr / foni 11 at rolling blinks, resulting in cracking of the n surface and inside the spit, .1 and therefore,

SP

about 1

deterioration in the quality of ingots of high carbon steel. When the ingot is rotated around its axis by 180 ° less than 2 hours before the end of heating, it does not have time to warm up evenly over the cross section. When an ingot is deformed, this causes additional stresses resulting in the formation of cracks on the surface and inside the ingot, and a deterioration in the quality of the blanks obtained from such ingots. When the ingot is rotated around its axis by 180 more than 3 hours before the end of heating, the temperature of the face that falls near the wall of the heating wells decreases, which leads to uneven heating and, when rolled, causes cracks on the heated side of the ingot, the quality of the blanks deteriorates.

Examples As an assessment of the effectiveness of the method, the yield of the suitable metal is expressed, expressed as a percentage of the metal being smelted, and the consumption of metal per rental in kilograms per tonne of good rolled metal. In the oxygen converter shop under the same conditions for the known and proposed methods for obtaining the preform were made (smelting, casting, crystallization) ingots of high-carbon steel grades 54-60 PP with a mass of 11.7 tons.

In the blooming workshop, the ingots are heated from a temperature of 830 ° C for 8.3 hours to 1260 ° C, and at an temperature of 830 ° C, isothermal aging is carried out for 0.5 hours, and 2.5 hours before the end of heating, the ingots are turned around its axis on

180s

Then from these ingots receive

blanks for the known and proposed methods. Ingot rolling is carried out on 1300 blooming on an intermediate section of 350x350 mm according to the reduction mode to a total reduction of 66% on one side and 62% on the other. The deformation in the first passes is carried out with a reduction of 27% along one and 25% along the other side of the ingot during subsequent reductions along the sides 20 and 19% of the total reduction along the side, respectively, after which the position of the roll is changed in the rolling line by turning to 90 ° counterclockwise during the roll and the final rolling is performed to the required size

0

five

0

five

0

five

0

five

0

five

150x150 mm with single crimping x 10-11% of the total crimping on the side.

The quality of the workpiece obtained by the proposed method is better compared with the known. The marriage of the workpiece on surface defects (flaw, crack) by a known method is higher by 1.2% than on the proposed. The yield and specific consumption of metal per rolled product by a known method is 77.0% and 1299 kg / ton, and according to the proposed method - 78.2% and 1279 kg / ton, respectively.

The results of testing the method of producing blanks from high carbon steel at the optimum, boundary and extreme parameters of the method, as well as by a known method, are shown in the table.

From the data of the table it is seen that when obtaining a billet of high carbon steels by the proposed method, the yield of the product due to an increase in the quality of the blanks increases by 0.9-1.2%, and the specific metal consumption per rolled is reduced by 15-20 kg per ton of good compared to with the famous.

Isothermal holding of ingots at 800 870 ° C less than O, A h does not limit the rate of their heating, which leads to a temperature difference between the outer and inner layers of the heated metal, causing significant thermal stresses between them, resulting in the formation of surface cracks and flaws on the workpiece, which reduces the yield.

Isothermal holding of ingots at 800–870 ° С and more than 0.6 h is not economically feasible, since this leads to an increase in the total heating time of the billet.

Claims (1)

Invention Formula Method for the production of billet of high carbon steels, including heating to 1250-1270 ° C, rolling on an intermediate section at a temperature not lower than 1100 ° C to a total reduction of 62-66% on each side of the ingot with compression in the first passes of 25-27% and subsequent single reduction of 19-20% of the total reduction, on the side, turning the roll at 90 ° and final rolling to the required size with single reductions by 10-11% of the total reduction on the side, characterized in that, in order to improve the quality of the workpiece and reduce the specific consumption Proposed In the process of heating, metal is rolled at 800-870 ° C isothermal aging for 0.4-0.6 hours, and 2-3 hours before the end of heating, the ingots are rotated around its axis by 180.