CN113198967B

CN113198967B - 8 megawatt main shaft die forging production process

Info

Publication number: CN113198967B
Application number: CN202110434746.3A
Authority: CN
Inventors: 闫振伟; 戚振华; 刘圣祥; 徐建东
Original assignee: Zhenhong Heavy Industry Jiangsu Co ltd
Current assignee: Zhenhong Heavy Industry Jiangsu Co ltd
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2022-08-26
Anticipated expiration: 2041-04-22
Also published as: CN113198967A

Abstract

The invention discloses a die forging production process of an 8 megawatt main shaft, which comprises the following working procedures in sequence: forging, heat treatment after forging, inspection, rough machining, secondary inspection, secondary heat treatment, physical and chemical detection and finish machining; in the forging and pressing process, the blank to be forged is placed into a special die to carry out rotary local forming on the blank. According to the invention, as forging and pressing are carried out, the large die forging product can be completed by small equipment only by using a press of 1 ten thousand tons, 46 tons of blanks are required to be fed by using the method in the prior art, and after the die forging process is adopted, 33 tons of blanks are required to be fed, the machining allowance is small, the steel ingot investment is reduced to 13 tons of blanks, and the raw material cost is saved.

Description

8 megawatt main shaft die forging production process

Technical Field

The invention relates to a die forging production process for an 8 megawatt main shaft.

Background

An offshore wind power plant is a novel power plant which generates power by using offshore wind resources. Under the condition of increasingly severe petroleum resource situation, all countries project eyes to sea areas with huge wind power resources, and a plurality of offshore wind power plants are built in a plurality of countries in Europe and are huge in scale. China also gradually relates to the field of offshore wind power generation, offshore wind power plants in Shanghai are started in 2010, and hong Kong in China intends to build the largest offshore wind power plant in China. With the increasing of the offshore wind power, the main shaft of a large wind power main unit, such as a large 8 megawatt main shaft, has a large size and a complex shape, and the diameter of the main shaft is about 2.9 meters, so that the tonnage of a press is not enough during die forging, and how to reduce the production cost of the product is a difficult problem faced by the existing wind power manufacturing enterprises.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an 8-megawatt main shaft die forging production process, the large die forging product can be completed by small equipment only by using a 1 ten thousand-ton press machine, 46 tons of blanks are required to be fed by using the method in the prior art, and after the die forging process is adopted, 33 tons of blanks are required to be fed, the machining allowance is small, the steel ingot investment is reduced to 13 tons of blanks, and the raw material cost is saved.

In order to achieve the purpose, the technical scheme of the invention is to design an 8 megawatt main shaft die forging production process, which comprises the following working procedures in sequence: forging, heat treatment after forging, inspection, rough machining, secondary inspection, secondary heat treatment, physical and chemical detection and finish machining; in the forging and pressing process, the blank to be forged is placed into a special die to carry out rotary local forming on the blank. Because the sectional pressing is carried out, the large die forging product can be completed by small equipment, 46 tons of blanks are required to be fed by using the method in the prior art, and after the die forging process is adopted at present, 33 tons of blanks are required to be fed, the machining allowance is small, the steel ingot investment is reduced to 13 tons of blanks, and the raw material cost is saved.

In the forging and pressing process, the steel ingot is kept warm by a holding furnace, then is taken out of the holding furnace, is chamfered, is staggered with a water gap and is cut off with a dead head, and then is sent into the holding furnace for heat preservation; the temperature of the holding furnace is 1250 ℃.

The further technical scheme is that after the steel ingot is sent into the heat preservation furnace again for heat preservation, the steel ingot is taken out of the heat preservation furnace and is subjected to upsetting, drawing out, upsetting again and end face flattening in sequence to form a blank, and then the blank is returned to the heat preservation furnace for heat preservation continuously.

The further technical scheme is that the blank is taken out of the heat preservation furnace and preformed, and the preformed blank is put into the heat preservation furnace again for continuous heat preservation.

The further technical scheme is that the blank is taken out of the heat preservation furnace and placed into a special die to carry out rotary local forming on the blank, the reduction is 80-100 mm in height each time, a central hole is punched after the blank is pressed and formed, and the aperture of the central hole is 550 mm. The existing equipment is 1 ten thousand tons, large die forging products are completed by small equipment, 46 tons of blanks are needed by using the method in the prior art, and 33 tons of blanks are needed by using the existing die forging process, so that the machining allowance is small.

The method further comprises the following steps that the special die comprises an upper die and a lower die, and the upper die and the lower die are preheated to 250-300 ℃; the lower die comprises a rotatable part, wherein a blank to be die forged is placed in the rotatable part, and the size of the rotatable part is larger than that of the blank to be die forged. The upper die is fixed on the movable sliding block of the press, so that the upper die can only move up and down and cannot move horizontally, and the upper die moves up and down along with the movable sliding block of the press, so that the pressing amount during die forging is realized.

The further technical proposal is that the rotatable part is a rotary turntable component which is connected with a hydraulic driving gear; the lower die also comprises a lower die pad arranged above the rotary turntable assembly, and an outer die ring is arranged above the lower die pad; and a gear ring meshed with the hydraulic driving gear is fixedly arranged on the outer side wall of the rotary turntable assembly.

The further technical scheme is that the lower die pad is annular, a positioning ring is convexly arranged on the upper surface of the lower die pad, and an annular groove matched with the positioning ring is arranged on the outer die ring; the outer die ring is in a circular ring shape, the inner wall of the outer die ring is in a step ring shape, and the maximum inner diameter of the inner wall of the step ring is larger than the size of the large-size end of the blank. Because the maximum inner diameter of the inner wall of the step ring of the outer die ring is larger than the size of the large-size end of the blank, enough space is provided for pressing and forming conveniently, and the consumption of raw materials of steel ingots is reduced.

The further technical scheme is that the upper die comprises a forming head for press forming and a cuboid which is integrally formed with the forming head and protrudes towards two ends, and the longitudinal section shape of the forming head is matched with the longitudinal section shape of an opening at the upper end of the middle part of the die forging blank.

The further technical scheme is that the steel ingot is 42CrMoA, the forging ratio in the forging and pressing process is not less than 3.5, the forging temperature is 850-1230 ℃, the forging fire frequency is 3-4 times, and the mass of the forged piece after die forging is 2.8 tons.

The invention has the advantages and beneficial effects that: due to sectional pressing, only 1 ten thousand tons of press machines are needed at present, large die forging products are completed by small equipment, 46 tons of blanks are needed by the blank using the method in the prior art, and only 33 tons of blanks are needed by the blank using the die forging process at present, so that the machining allowance is small, the steel ingot investment is reduced to 13 tons of blanks, and the raw material cost is saved. Because the maximum inner diameter of the inner wall of the step ring of the outer die ring is larger than the size of the large-size end of the blank, enough space is provided for pressing and forming conveniently, and the consumption of raw materials of steel ingots is reduced.

Drawings

FIG. 1 is a schematic diagram of a mold involved in an 8 megawatt spindle forging process of the present invention;

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is a schematic structural diagram of the outer mold ring of FIG. 2;

FIG. 4 is a cross-sectional view of FIG. 3;

FIG. 5 is a schematic view of the upper mold of FIG. 1;

FIG. 6 is a schematic view of the lower die pad of FIG. 2;

FIG. 7 is a cross-sectional view of FIG. 6;

FIG. 8 is a schematic view of the shape of the ingot before swaging;

FIG. 9 is a preformed shape of the blank;

FIG. 10 is a schematic illustration of the billet after swaging;

fig. 11 is a schematic view of an original free end blank.

In the figure: 1. an upper die; 2. a blank; 3. rotating the turntable assembly; 4. a hydraulic drive gear; 5. a lower die cushion; 6. an outer mold ring; 7. a toothed ring; 8. a positioning ring; 9. a ring groove; 10. a forming head; 11. a cuboid; 12. the upper end is open.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The invention relates to a die forging production process of an 8 megawatt main shaft, which comprises the following working procedures in sequence: forging (shown in fig. 8, which is a schematic diagram of a steel ingot), heat treatment after forging, inspection, rough machining, secondary inspection, secondary heat treatment, physical and chemical detection and finish machining; in the forging and pressing process, the blank to be forged is placed into a special die to carry out rotary local forming on the blank. In the forging and pressing process, the steel ingot is taken out of the holding furnace after being held by the holding furnace, then chamfered, processed with a wrong sprue and a chopped riser, and then sent into the holding furnace for heat preservation; the temperature of the holding furnace is 1250 ℃. And after the steel ingot is sent into the heat preservation furnace again for heat preservation, taking the steel ingot out of the heat preservation furnace, sequentially upsetting, drawing out, upsetting again, flattening the end face to form a blank, and returning the blank to the heat preservation furnace for heat preservation continuously. Taking out the blank from the holding furnace, preforming the blank (the preformed shape is shown in figure 9), and putting the preformed blank into the holding furnace again to keep the temperature. And (3) taking the blank out of the heat preservation furnace, putting the blank into a special die, performing rotary local forming on the blank, wherein the reduction is 80-100 mm in height each time, punching a central hole after press forming, and the aperture of the central hole is 550mm (the schematic diagram after blank die forging is shown in figure 10). Compared with the original free forging (as shown in figure 11), the ingot investment is reduced by 13 tons. The die, as shown in fig. 1 to 7, comprises an upper die 1 and a lower die, the lower die comprising a rotatable member in which a blank 2 to be swaged is placed, the rotatable member having a size larger than that of the blank 2 to be swaged. The rotatable part is a rotary turntable component 3, and the rotary turntable component 3 is connected with a hydraulic driving gear 4; the lower die further comprises a lower die cushion 5 arranged above the rotary turntable assembly 3, and an outer die ring 6 is arranged above the lower die cushion 5. A gear ring 7 meshed with the hydraulic driving gear 4 is fixedly arranged on the outer side wall of the rotary turntable component 3. The lower die cushion 5 is annular, a positioning ring 8 is arranged on the upper surface of the lower die cushion 5 in a protruding mode, and an annular groove 9 matched with the positioning ring 8 is formed in the outer die ring 6. The outer die ring 6 is annular, the inner wall of the outer die ring is in a step ring shape, and the maximum inner diameter of the inner wall of the step ring is larger than the size of the large-size end of the blank 2. The upper die 1 includes a forming head 10 for press forming and a rectangular parallelepiped 11 formed integrally with the forming head 10 and protruding toward both ends, and the longitudinal sectional shape of the forming head 10 matches the longitudinal sectional shape of an opening 12 at the upper end of the middle of the die forging blank.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

The 1.8 megawatt main shaft die forging production process is characterized by comprising the following working procedures in sequence: forging, heat treatment after forging, inspection, rough machining, secondary inspection, secondary heat treatment, physical and chemical detection and finish machining; in the forging and pressing process, a blank to be forged is placed into a special die to perform rotary local forming on the blank, the reduction amount is 80-100 mm in height each time, a central hole is punched after the pressing forming, and the aperture of the central hole is 550 mm; the steel ingot used in the forging process is 42CrMoA, the special die comprises an upper die and a lower die, the upper die and the lower die are preheated to 250-300 ℃, the upper die comprises a forming head for press forming and a cuboid which is integrated with the forming head and protrudes towards two ends, and the longitudinal section shape of the forming head is matched with the longitudinal section shape of an opening at the upper end of the middle part of a die forging blank; the lower die comprises a rotatable part, a blank to be die forged is placed in the rotatable part, the size of the rotatable part is larger than that of the blank to be die forged, the rotatable part is a rotary turntable assembly, a gear ring meshed with the hydraulic driving gear is fixedly arranged on the outer side wall of the rotary turntable assembly, and the rotary turntable assembly is connected with the hydraulic driving gear through the gear ring; the lower die also comprises a lower die pad arranged above the rotary turntable assembly, a positioning ring is convexly arranged on the upper surface of the lower die pad, an outer die ring is arranged above the lower die pad, and the outer die ring is provided with a ring groove matched with the positioning ring; the outer die ring is annular, the inner wall of the outer die ring is in a stepped annular shape, and the maximum inner diameter of the inner wall of the stepped annular is larger than the size of the large-size end of the blank to be die forged.
2. The die forging production process for the 8 megawatt main shaft according to claim 1, wherein in the forging and pressing procedure, the ingot is kept warm by a holding furnace, then is taken out of the holding furnace, is chamfered, is staggered with a water gap and a riser, and then is sent into the holding furnace for heat preservation; the temperature of the holding furnace is 1250 ℃.
3. The die forging production process for the 8 megawatt main shaft according to claim 2, wherein after the steel ingot is sent into the holding furnace again for heat preservation, the steel ingot is taken out from the holding furnace to be subjected to upsetting, drawing, re-upsetting and end surface flattening in sequence to form a blank, and then the blank is returned to the holding furnace for heat preservation continuously.
4. The die forging process for the 8 megawatt main shaft according to claim 3, wherein the blank is taken out from the holding furnace and preformed, the preformed blank is put into the holding furnace again for continuous heat preservation, and the blank to be die forged is obtained after the preformed blank is taken out.
5. The die forging production process for the 8 megawatt main shaft according to claim 4, wherein the forging ratio in the forging and pressing process is not less than 3.5, the forging temperature is 850-1230 ℃, the forging fire time is 3-4, and the mass of the forged piece after die forging is 28 tons.