SU1563796A1 - Method of producing hollow billet having a bottom - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular to methods for producing a hollow billet with a bottom. The purpose of the invention is to expand technological capabilities and improve the quality of products. The original billet of hard steel or alloy is heated to a hot deformation temperature. After that, the blank is stamped on a hydraulic press into a semifinished product in the form of a glass with a bottom. After punching, a core of ductile metal is installed in the cavity of the cup. The resulting assembly (C) is additionally heated to the required temperature. Screw rolling C is carried out with a draw ratio of 1.3 - 1.6. After rolling, C is sewn in the helical rolling mill to the depth of the mandrel. In this case, screw rolling and piercing C is carried out with a total draw of at least four. C is drawn through rings on a hydraulic press. Expansion of technological capabilities and improving the quality of the workpiece is provided by improving the physicomechanical properties of the workpiece material. 1 tab., 1 Il.

Description

The invention relates to the processing of metals by pressure and can be used for the production of hollow billets with a bottom of high-strength steels and alloys used for heavy-duty loaded parts for special purposes.

The purpose of the invention is to expand technological capabilities and improve quality by improving the physicomechanical properties of the workpiece material.

The drawing shows a flow chart for the production of hollow billets with a bottom.

The main operations are: 1 - heating of the initial billet (ingot); 2 - stamping the workpiece with obtaining a semi-finished product in the form of a glass; 3 - placement in the cavity of the semifinished rod of plastic material and additional heating of the assembly of the semifinished product with the rod; 4 - screw rolling with a stretch ratio of 1.3-1.6; 5 - flashing of the assembly in the helical rolling mill on the mandrel to the depth of the rod; 6 — stretching a semifinished product through rings on a hydraulic press; 7 - prefabricated.

The process is as follows.

The initial billet or ingot of hard-to-deformed steel or alloy of a relatively short length is heated to the temperature of hot deformation and stamped on a hydraulic press to obtain a semi-finished product in the form of a glass. A plastic metal rod is placed in the cavity of the semifinished product;

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heating the assembly to a temperature of hot deformation and subjected to helical rolling in one or several passes. Then, the assembly is stitched in a helical rolling mill to the depth of the core and is drawn through rings on a hydraulic press. When stamping the original billet in the press, the ratio of the depth of the pierced hole and the diameter should not exceed 4 (L / d.4), otherwise, due to the high resistance of the metal deformation, the press tool (punch) can be bent or broken.

Based on the experimental dango alloy in this case, the insignificant and important advantage of the helical rolling process (transverse rolling) is essentially not realized. When large axial forces occur on the mandrel, since the cross-sectional area of the mandrel used in helical rolling will be less than 1/4 of the cross-sectional area of the mandrel used in the drawing process, therefore, the effect of the mandrel on the gain in this case is hardly noticeable. Large axial forces of the metal on the mandrel cause loss of stability of the reference rod, its accidental failure.

Firmware billet with mandrel osuschestnyh, obtained as a result of deformed ... for ° Dean passage before touching toe

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vanilla hollow billets of high-strength alloy EK-31, equipped with a rod of ductile metal, such as carbon steel, in a three-roll helical rolling mill, and further metallographic

mandrel bottom of the workpiece. The amount of reduction in this case is limited by significant metal forces on the deforming tool and intensive deformation by heating the alloy. Firmware inserts from studies of rolled specimens of the set-20 EC-31 juice-resistant alloy with a mandrel from

It has been found that the depth of penetration of plastic deformation into the central zones of the workpieces depends on the magnitude of the stretch ratio. In those zones of cross-sections of the samples where plastic-carbon steel took place, it was shown that with an increase in the stretching ratio above 1.6, there was a discontinuity in the outer layers of the workpiece due to deformation heating, and with its significant deformation, there was a fine 25 less than 1, L dramatically increases the level of the equiaperist structure, predetermined by the u - - - in--

schA high physical and mechanical properties. At small values of the stretch ratio (, 8), the deformation was concentrated in the peripheral zones of the workpiece, located at a distance of 0.6–1.0 from the cross-section radius from the center. However, with an increase in the stretching ratio to –C, 4, the penetration of plastic deformation into the central zones of the workpiece was observed. In this case, the structure of the samples was 3g fine-grained and uniformly worked over the entire cross section of the wall, which led to an increase in the basic mechanical characteristics of the alloy by 1.5-1.8 times. At the same time, the antizotropic properties that took place after the pressing process almost disappeared.

Rolling high-strength alloys is accompanied by intense deformation heating of the outer layers, which, with a certain critical value, may be an example of the study of the material of the product.

Thus, for the structure to be evenly processed over the cross section, it is necessary to obtain at least 4 stretches by means of helical rolling and piercing, while the stretching should be 1.3-1.6 when piercing.

After flashing, the sleeve is drawn through the matrix rings on the hydraulic press, whereby the outer surface takes the form of a regular circle, the traces of the helix on the outer surface after the piercing mill are smoothed.

The results of the research are summarized in the table.

40 This is followed by mechanical treatment by traditional methods.

Example 1. According to this method, thick-walled hollow billets with a diameter of 67 mm with a wall thickness of 19.7 mm and a bottom thickness of 30 mm were made from hard-to-distant material. . , lh,., „..„ ........ -r -... ,,

lead to annular destruction of the workpiece. nickel based alloy

Therefore, high exhaust ratios of 5 or more are usually achieved in several passes.

The ratio of the diameter of the mandrel to the stitched hole in the liner plays an important role in flashing the core bar.

On the basis of experimental studies, it was also established that the inner diameter of the sleeve d, should be larger than 50

EK-31. The initial billet is an ingot of electroslag remelting with a diameter of 120 mm and a length of 180 mm. The ingot was heated to 1160-180 ° C and subjected to stamping on a hydraulic press with a force of 6300 tons into a glass with an outer diameter of 130 mm.

The diameter of the pierced cavity was 60 mm, depth 158 mm. In the cavity, a core made of plastic material, for example carbonaceous material, was placed on a hot fit.

do core meter after helical rolling55 steel 45, heated the billet to 1160

1.1-2 times. Fulfillment, ld0 scool-1180 ° C and rolled in a three-roll mill sets to poor quality and increased helical rolling to a diameter of 75.8 mm

noostennosti stitched sleeves, as burn - (, 94) for several passes (core

This wall of the rod from hard-to-reduce to a diameter of 15 mm). Further

In this case, the alloy is insignificant and the important advantage of the helical rolling process (transverse rolling) is essentially not realized. When large axial forces occur on the mandrel, since the cross-sectional area of the mandrel used in helical rolling will be less than 1/4 of the cross-sectional area of the mandrel used in the drawing process, therefore, the effect of the mandrel on the gain in this case is hardly noticeable. Large axial forces of the metal on the mandrel cause loss of stability of the reference rod, its accidental failure.

The workpiece with the mandrel is pierced through the ° Dean before it is touched

ppp and u p h tp s R nuuuuQ pLmgatma t

mandrel bottom of the workpiece. The amount of reduction in this case is limited by significant metal forces on the deforming tool and intensive deformation by heating the alloy. Firmware blanks of high-strength alloy EK-31 with a mandrel of

Juice strong alloy EK-31 with a mandrel of

carbon steel showed that with an increase in the stretching ratio above 1.6, there is a discontinuity in the outer layers of the workpiece due to deformation heating, and when its value is less than 1, L increases by the right level.

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dimensionality of the study of the material of the product.

Thus, for the structure to be evenly processed over the cross section, it is necessary to obtain at least 4 stretches by means of helical rolling and piercing, while the stretching should be 1.3-1.6 when piercing.

After flashing, the sleeve is drawn through the matrix rings on the hydraulic press, whereby the outer surface takes the form of a regular circle, the traces of the helix on the outer surface after the piercing mill are smoothed.

The results of the research are summarized in the table.

0 This is followed by mechanical processing by traditional methods.

Example 1. According to this method, thick-walled hollow billets with a diameter of 67 mm with a wall thickness of 19.7 mm and a bottom thickness of 30 mm were made from difficult-to-wear materials

nickel-based alloy

EK-31. The initial billet is an ingot of electroslag remelting with a diameter of 120 mm and a length of 180 mm. The ingot was heated to 1160-180 ° C and subjected to stamping on a hydraulic press with a force of 6300 tons into a glass with an outer diameter of 130 mm.

The diameter of the pierced cavity was 60 mm, depth 158 mm. In the cavity, a core made of a floating bar was placed on a hot fit with a drill with a diameter of 15 mm, heated to 1160–1180 ° C and pierced in a two-roll helical rolling mill MISiS-1ZOD on a mandrel with a diameter of 30 mm (dr / dc 2 ratio, Q) into a sleeve with a diameter of 69.4 mm with a wall thickness of 19.7 mm (p. 1.47). The firmware process was stable, the spacing of a batch of 10 Le pieces of sleeves exceeded 1.5 mm. The resulting liners had a clean outer and inner surface. At the same time, the metal of the core evenly covered the hole along the entire length. The total stretching during rolling and flashing was 4.32. Next, the sleeve-glass heated to 980-1000 ° С was subjected to the operation of drawing through rings on a hydraulic press with a force of 6300 tons with deformation on the outer diameter from 69.48 to 67 mm. After that, the outer surface had the shape of a regular circle, no scratches and burrs were found on the surface. The resulting liners also had a clean inner surface, the core metal evenly covered the inner surface.

Example 2. The spiral-rolled rods from the MISiS-130T mill, rods of high-strength EK-31 alloy with a diameter of 75.8 mm and a steel core of 15 mm with a diameter of 15 mm were pierced in a two-roll helical rolling mill MISiS-130D on a mandrel with a diameter of 26 mm (dr / dc ratio 1.73) before touching the bottom of the workpiece with the toe of the mandrel. Hollow sleeves with an outer bottom diameter of 65.3 mm and a wall thickness of 19.6 mm were obtained. The sweep rate was 1.6. The process of the firmware flowed steadily, the difference in the batch of 6 pieces. did not exceed 1.7 mm. The resulting sleeves had a clean internal surface without captivity and scratch, the grain was uniformly crushed on the macrosections along the wall thickness, and there was no anisotropy of properties. Attempting to achieve, when flashing, a draw ratio of more than 1.6, due to the reduction of the rolls, led to a breakdown of the metal continuity in the outer layers of the workpiece due to the large deformation heating and, as a result, significant thermal stresses

Thus, in order to obtain a fine-grained structure uniformly worked through the wall thickness, the stretch ratio for flashing should not be more than 1.6.

Example 3. An electroslag remelting ingot of high-strength EK-31 alloy with a diameter of 120 mm and a length of 180 mm was heated to 1160-1180 ° C and subjected to stamping on a hydraulic press with a force of 6300 tons into a glass with an outer diameter of 130 mm. The diameter of the stitched cavity sos

50

five

0

tavl 60 mm. depth - 158 mm. In the cavity, a core of carbon steel 45 was placed on a hot fit, the billet was heated to 1160–1180 ° C and rolled in a MISiS-130 T three-roll helical rolling mill to a diameter of 82.2 mm with a draw, 5 (core was reduced to 16 mm). The obtained bar was centered with a drill with a diameter of 16 mm, heated to 1160-1180 ° C and pierced in a two-roll helical rolling mill MISiS-130D on a mandrel with a diameter of 30 mm into a sleeve with a diameter of 71.6 with a wall thickness of 20.8 mm (, 6)

The processes of screw rolling and firmware proceeded steadily. The total stretching was equal to 4. The sleeves obtained had a well-developed internal structure, the grain being evenly crushed both along the wall / hook thickness and along the thickness of the liner bottom. This led to an increase in the basic physical and mechanical properties of 1.5-1.8 times compared with the same characteristics of the alloy after the punching operation. However, with a decrease in the total exhaust to the values, metallographic studies showed the presence of unworked areas of the internal structure, especially in the central zones of the bottom of the liner. This made it possible to conclude that it is necessary to use large extrusions during helical rolling of coils (, 5), which make it possible to achieve a good design of the structural components throughout the cross section of the billet.

The invention allows to expand the technological capabilities and improve the quality by improving the physicomechanical properties of the material of the workpiece.

Claims (1)

Invention Formula A method of producing a hollow billet with a bottom, predominantly of a high-strength alloy, including heating, stamping the original billet to produce a semi-finished product in the form of a glass and drawing it through rings, characterized in that, in order to expand the technological capabilities and improve the quality of products by improving the physicomechanical properties materials of the workpiece, after punching into the cavity of the semifinished product, a rod of ductile metal is installed, the assembly is additionally heated, after which its screw rolling is carried out with With a draw ratio of 1.3-1.6, and before drawing, the assembly is stitched in a screw rolling mill on a mandrel at the depths of the rod, while screw rolling and piercing is carried out with a total stretch of at least four.