SU1102816A1 - Method for making steel ring-shaped products - Google Patents

Abstract

METHOD OF MANUFACTURING STEEL RING PRODUCTS, including anti-flocation treatment by heating and holding for 3-6 hours, heating to a rolling temperature, rolling and heat treatment, characterized in that, with the aim of increasing productivity and improving quality by more complete removal of hydrogen, aging t at 900-1000 ° C. (L

Description

I The invention relates to heat treatment and can be used in the manufacture and heat treatment of ring products such as rings, flanges, bearing rings, etc. A method is known for the manufacture of ring products, including heating the billet, piercing it, molding, rolling and subsequent anti-floc treatment of finished products C 13K the disadvantages of this method include the low quality of the finished product due to incomplete removal of hydrogen from the metal, due to low temperature products in the feet up to 15 That, ultimately, it is reflected on the end-use characteristics of the product. Closest to the proposed by the technical essence and the achieved result is a method of manufacturing railway wheels by heating the billet, its molding, rolling and anti-flocking processing, carried out in two stages: the first is by heat recovery of billets for 3-6 hours ; the second is by isothermal holding of finished wheels for 4 hours at 650680 ° C. 2. A disadvantage of the known method is the lack of substantial removal of hydrogen from the metal at 650bVO C on both stages. In addition, this method is characterized by low productivity due to 4 hours of anti-flock processing of finished products (wheels). The purpose of the invention is to increase productivity and improve quality by more completely removing hydrogen. This goal is achieved by the fact that according to the method of manufacturing steel ring products, including anti-flocation treatment by heating and holding for 3-6 hours, heating to the rolling temperature, rolling and heat treatment is carried out at 900-1000 ° C. Lower limit (900 ° C ) was determined from the conditions of the most efficient removal of hydrogen and the minimum metal loss. Heating above 1000 ° C leads to significant irretrievable metal losses in the scale, as well as to significant energy consumption. 16 Example. In the open-hearth shop at the casting, samples are taken of low-alloyed liquid steel with a carbon content of 0.55% and analyzed for hydrogen content. Ingots weighing 4.5 tons, cut into blanks weighing 500 kg. Billets analyze n-and the hydrogen content, then treated according to the proposed and known 22 methods. According to the proposed spostebu, the anti-flocking processing of the blanks is carried out at 950 C for 5 hours, then heated to 1200 C under deformation, held for 3 hours, rolled on a rough and finishing cage, receiving power rings with an outer diameter of 1000 mm, an inner diameter of 700 mm and a height of 150 mm Laminated rings are collected in the foot and, not allowing the temperature to drop below 600 ° C, are set in a furnace, where they are heated for 800 hours under heat treatment. At this temperature, the stresses after rolling are removed and, therefore, the protofloc processing of finished isdetsikl production. After heating for heat treatment, the rings are quenched and released at 450 ° C for 3 hours. The kinetics of hydrogen removal in the manufacture of steel ring products using the proposed method and the prototype method are shown in the table. The abrupt decrease in the solubility of hydrogen in the steel when it is transferred from the liquid to the solid state causes the elimination of this element in the process of crystallization. The concentration of hydrogen naturally increases from the periphery to the center and from the profitable part of the ingot to the bottom. The average hydrogen content in the blanks from the bottom of the ingot is 8.0-6.0 cm / 100 g, which is 2-1.5 g higher than in the blanks of the head and central part of the ingot. Pre-anti-floc treatment of workpieces at 650 ° C does not lead to a noticeable removal of hydrogen, so its content remains at the same level as when cutting ingots. when heating blanks for rolling up to 1200 C, hydrogen is noticeably removed throughout the cross section of the blank and remains 1 s depending on the initial distribution in the billet at the level of 3.85, 0 cm / OO g. After hot plastic deformation, there is no noticeable change in hydrogen content in the elements of the product. Anti-flocation treatment, further heating under heat treatment up to 800 ° C and tempering to noticeably removing hydrogen from the product does not result. Hydrogen is intensively removed from massive billets of medium-carbon, low-alloyed (open-hearth 1x steels at the high-temperature heating stage. The remaining heating operations are almost do not lead to the release of hydrogen from the metal and the flocculation of the steel of the aetc lows is insignificant. Due to the deeper removal of hydrogen during the anti-flocation quipment, prior plastic deformation, there is no need for a second stage protivoflokennoy treatment after plastic deformation. As a result, the reduction is achieved of the production cycle by about 20%, which in turn leads to increased productivity. annual economic effect is about 640 thousand.

12549 Temperature, with

20

Holding time, h

5.0

5.05, 2 5.2

31551 Temperature, ° С

20

Time exposure.

h

Content

Ng

cmE / 100 g 7.0 7.0

1200 1200

950

650

4.04, 12, 83, 94, 8, 5 3.6 3.0

1200 1200

650

950

3

4.24, 5З. Ог 4.9 3,2 5,0 4,8

12549 Temperature, with

20

800

Table continuation

450

450

20

20

Claims (1)

METHOD FOR PRODUCING STEEL RING ITEMS, including anti-flock treatment by heating and holding for 3-6 hours, heating to rolling temperature, rolling and heat treatment, characterized in that, in order to ^: increase productivity and improve quality by more complete removal of hydrogen, aging carried out at 900-1000 ° C.