SU555961A1 - Method of forging forgings like rolls with an axial bore of ingots - Google Patents

Description

one

The invention relates to the field of metal forming and can be applied in the engineering industry in the manufacture, for example, of support rolls for rolling mills.

There is a known method of forging forgings of the type of rolls with an axial orifice of large ingots, including ingot ingot operations, block cutting of an ingot, sludge, an axial bore piercing and preliminary drawing on the mandrel.

The disadvantage of this forging method is the following: the method is available for the inner hole through the necks for a limited group of stepped hollow forgings with a small section of the barrel and necks. If there is a significant difference in the cross sections of the bore hole on the necks, this can lead to the appearance of longitudinal cracks at their ends.

The known forging method also does not sufficiently work out the structure along the section of large forgings such as hollow rolls, in which grain growth from the surface to the hole is observed. The unevenness of the structure over the section of the forging causes a decrease in the mechanical properties and durability of the part in operation.

The aim of the invention is to expand the range of forging of stepped hollow rolls with a large cross section difference between the necks and the barrel, reducing the internal hole bore on the necks of the stepped hollow of the empty rolls, increasing the metal flow in

longitudinal direction after zdaleniya mandrel.

This is achieved by the fact that according to the proposed method, after preliminary drawing on the mandrel, the inner surface of the workpiece

is cooled to a temperature of 150-200 ° C and lower than the temperature of the sprinkled surface of the workpiece, after which it is forged to the final dimensions, continuing to cool the surface of the axial bore without a mandrel.

The essence of the invention is as follows.

Known methods of forging are as follows: by biliteration, block cutting, draft, and hollow piercing of the hole, and the hollow billet with technological projections under the forks is forged on the mandrel. To obtain the final dimensions of the forging, the forging of the workpiece is conducted without a mandrel.

with preliminary compulsory cooling of the surface of the hole, providing the temperature difference between the outer layers of the product and the surface of the hole at 150–200 ° C and with the preservation of this pin in

forging process.

The proposed method is illustrated in the drawing.

In the drawing, the following designations are given: 1 - billet after forging on the ground; 2 — sprayer for cooling the surface of the hole; 3 - forging, forged without a mandrel with forced cooling.

After making the hollow blank 1, a sprayer 2 is installed in the opening of the blank, which has multiple openings for spraying the coolant (for example, compressed, humidified air or other energy carrier). After cooling the surface of the hole to a temperature of 150-200 ° C below the temperature of the outer layers, forging 3 is forged to the required size without a mandrel. Cooling is carried out throughout the forging process.

The described forging method can be applied for the manufacture of support rolls for rolling mills and will ensure satisfactory study of the metal structure during forging and heat treatment, improve the quality of the support rolls and thereby increase their service life.

The durability of rolls made in this way will increase by 5--8%.

An example of the method. Held forging roll with an axial bore. Forging weight 75,000 kg, material 9HF. As a blank, an ingot weighing 120,000 kg is used. The forging is carried out for five removals under pressure with a force of 10,000 ton-force.

In the first removal, a chuck was made for profit, chambered to a diameter of 1850 mm, a cabin was cut, and a block was cut off with a length of 4250 mm. Then the block is sent for heating to 1200 ° C.

During the second removal of the workpiece, the billet is upset to a diameter of 2500 mm and pierced with a hollow forgiveness with a diameter of 600 mm. Next, the workpiece is again heated to 1200 ° C.

In the third removal, a mandrel is made on a mandrel with a diameter of 415-485 mm to a billet with technological projections with a diameter of 2000 mm and a length of 1025 mm each. The mandrel is then removed and a pipe having a diameter of 50 mm is introduced through which an air mixture is supplied. With this mixture, the surface is cooled to 850 ° C.

Next, the protrusions are made up to a diameter of 1750 mm and the barrel is hooked up. Forced cooling continues until the end of the forging in this removal. The degree of deformation should not exceed 10-15%. And the temperature interval is maintained in the range of 1200-750 ° C.

The fourth and fifth removals were performed in the range of 1050–750 ° C with forced cooling of the surface of the axial orifice to 800 ° C in the metal deformation zone, i.e., when the tapped end was pulled, forced cooling was conducted from the treated bone. The notched end extends to a diameter of 1190 mm and

then with a tapered transition to a diameter of 700 mm and a length of ISO, mm. After the roll neck has been formed, a technological overhang on the barrel is produced to a diameter of 1675 mm. Forging the opposite end is carried out in a similar manner.

After the formation of the second neck is completed, the supply of the air / water mixture is stopped and the forgings are smoothed and axially edited.

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Claims (1)

Invention Formula The method of forging forgings of the type of rolls with an axial hole with a hole of ingots, including the operation of heating the ingot, cutting down the block from it, precipitations, piercing of the axial hole and preliminary stretching on the mandrel, characterized in that, in order to remove the bore hole and increase the metal flow in the longitudinal direction, after preliminary stretching on the mandrel, the inner surface of the workpiece is cooled to a temperature of 150-200 ° C below the temperature of the outer surface of the workpiece, after which the forging is made to the final dimensions, without mandrels continue to cool the surface of the axial hole. i.O.eS