SU1353830A1 - Method of heat treatment of massive articles - Google Patents

Abstract

The invention relates to the field of mechanical engineering and is intended for cooling bulk products during their heat treatment. The purpose of the invention is to improve the quality of products, ensuring uniform cooling of products of variable cross section. The method includes multiple dipping of the products in a quenching medium with perforation in air until the temperature equalizes over the cross section of the product. The product is held in a quenching medium until the end of its surface luminescence, and after cooling below the temperature of the onset of the elastic state, the product is cooled without hardening in the quenching medium. Cooling is carried out in a perforated casing, the holes in which are opposite to the more massive parts of the product have a larger diameter than the holes in front of the less massive parts. 1 hp f-ly, 1 tab., 1 ill. i (L 00 SL CO 00 with

Description

one

The invention relates to mechanical engineering and is intended for cooling bulk products during their heat treatment.

The purpose of the invention is to improve the quality of products and ensure uniform cooling of products of variable cross section.

135

The drawing shows the scheme of realization — IQ was placed in a perforated casing, of the proposed method.

The method is carried out as follows.

The product 1 heated to the quenching temperature is placed in a perforated casing 2, lowered into the quenching medium and kept there until the end of its surface glow, after which the product is removed from the quenching medium

until the temperature equalizes over its cross section. After that, the product is again lowered into the quenching medium, suspended in it until the end of the luminescence of its surface, then removed from the quenching medium and held in air, lowered into the medium again, etc. Such a bathing of a product with exposure to a quenching medium and the possibility of openings of which opposite to more massive parts of the product was greater than the density of openings opposite to less massive parts. Cooling of the product in the casing from the temperature of heating for quenching to the temperature of the beginning of the elastic state (500 ° C)

It was carried out by repeatedly dipping it into a bath of water and removing the product with a holder for cooling.

its surfaces up to 500 ° C. After each dip, the part was held above water for 5–8 s to determine its temperature in section 25. The temperature was controlled by a thermocouple installed in the casing with an accuracy of + 16 ° C. Further cooling to the temperature of the martensitic transformation was also carried out at the expense of the spirit before the product reaches repeated dipping of the part at any temperature at the beginning of the elastic joint into the water, but without turning it back into water, after which the cooling in the quenching medium was used are without exposure in it, i.e. after being lowered into the quenching medium, the product is immediately taken out of it, drained in air, lowered into the medium and removed from it, etc. After the end of martensitic

35

crippling medium. After filling the casing with water, the part with the casing rose from the bath, after which it was also held above the water to equalize its temperature for 15 seconds. .

After quenching, the part was subjected to tempering (650 ° С - 2 h).

transformations in the product, its cooling is completed. The diameter of the holes 3 of the casing 2 opposite the more massive parts 4 of the product is larger than the diameter of the holes 5 opposite the less massive parts 6.

The proposed method was tested with g with the modes used are given in

heat treatment of preventer bodies

the table.

Normalization

380 720 19 197 Ferrite, 4-5

perlite

Normalization, zakr13538302

from steel 40XH. Since this product has different wall thicknesses, to increase the uniformity of cooling of its cross sections, the coolant was supplied unevenly: more massive parts were supplied with a larger amount of cooling medium than less massive ones. For this product, the openings of which, opposite the more massive parts of the product, were greater than the density of the holes opposite the less massive parts. Cooling of the product in the casing from the heating temperature for quenching to the temperature of the beginning of the elastic state (500 ° C)

its surfaces up to 500 ° C. After each dipping, the part was held above water for 5–8 s to determine its temperature in section 5. The temperature was controlled by a thermocouple installed in the casing with an accuracy of + 16 ° C. Further cooling to the martensitic transformation temperature was also carried out due to repeated dipping of the part in the casing into water, but without putting it into the water.

five

crippling medium. After filling the casing with water, the part with the casing rose from the bath, after which it was also held above the water to equalize its temperature for 15 seconds. .

After quenching, the part was subjected to tempering (650 ° С - 2 h).

The results of mechanical tests and studies of the structure of steel after heat treatment of the body of preventers according to the proposed method in comparison

the table.

As shown by the test results, the proposed method as compared with the known method provides a higher level of mechanical characteristics and a finer structure;

Claims (2)

1. The method of heat treatment of massive products from iron-carbon alloys, including cooling by repeatedly dipping them into the quenching medium with exposure in it and exposure to air until the temperature equalizes over the cross section of the product, characterized in that, in order to improve the quality of products, exposure in the quenching medium, is carried out until the end of the candle. and its surface is cooled until the product reaches the temperature of the beginning of the elastic state, and then they are repeatedly dipped without exposure to the quenching medium. 2. The method according to claim 1, about t and h and y - y and so that, in order to ensure uniform cooling of products of variable cross section, cooling is performed in a perforated casing, the holes in which opposite the more massive parts of the product have a larger diameter, and opposite the less massive parts - holes of a smaller diameter. Level liOHa / iovHou among / Compiled by G. Maksimenko Editor V. Petrash Tehred M. Khodanych Proofreader M. Maksimishinets Order 5673/26 Circulation 550Subscribe VNIIPI USSR State Committee for cases of discoveries and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4