Rolling method of high-temperature alloy strip-shaped forge piece

Abstract

The invention discloses a rolling method of a high-temperature alloy strip-shaped forge piece. The rolling method comprises the following steps: firstly, carrying out modified forging on a high-temperature alloy blank by adopting three-upsetting and three-drawing; upsetting, punching, trestle chambering and rolling are conducted on the high-temperature alloy blank subjected to reforging to form a high-cylinder thin-wall ring piece, and the inner diameter size of the ring piece is 85%-90% of the outer diameter size; cutting the high-cylinder thin-wall ring piece into two semicircular ring pieces by using linear cutting; and then straightening is conducted under a forging hammer, and two strip-shaped forgings are obtained. According to the method, the defects that the forge piece is uneven in thickness, poor in structure uniformity, large in forging heating number and the like are effectively overcome, the quality of the forge piece is improved, and the production efficiency is improved. The method is used for producing the high-temperature alloy strip-shaped forgings.

Description

Technical Field

[0001] The present invention relates to a rolling method for bar forgings, and particularly to a rolling method for superalloy bar forgings. Background Art

[0002] Bar-shaped parts are a commonly used structural component. Currently, for the forming of such forgings, the open-die forging method is usually adopted, that is, forging is carried out by an open-die hammer to make it bar-shaped. The biggest drawback of this method is that the thickness of such forgings is small, the temperature drops too fast during forging, and the deformation resistance increases rapidly, resulting in different thicknesses for each hammer forging, leading to uneven thickness of the final bar forging. Moreover, due to inconsistent deformation amounts at each part, the tissue uniformity of the forging is poor, usually requiring multiple forging heats, increasing energy consumption and prolonging the production cycle. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a rolling method for superalloy bar forgings to produce plate forgings. By adopting the ring rolling method, the forgings are made into high-cylinder thin-wall ring forgings, and then cut and straightened into bar forgings, effectively avoiding defects such as uneven thickness of the forgings, poor tissue uniformity, and multiple forging heats, improving the quality of the forgings and the production efficiency.

[0004] To solve the above technical problem, the rolling method for superalloy bar forgings of the present invention includes the following steps in its technical solution:

[0005] Heat the superalloy bar cut according to specifications to 980°C and hold for heat according to effective thickness × 8 min / 10 mm; perform upsetting, drawing out, and rolling into a circle three times for forging improvement, and air-cool after forging; the final forging temperature is greater than or equal to 880°C;

[0006] Reheat the forged blank to 850°C and hold for heat according to effective thickness × 8 min / 10 mm; then perform upsetting to obtain a solid cylinder; then punch the solid cylinder to obtain a hollow cylinder, and the inner diameter dimension of the hollow cylinder is 30% - 40% of the outer diameter dimension;

[0007] Expand the inner diameter of the hollow cylinder to 60% - 65% of the outer diameter dimension by using a mandrel expander; then put it on a ring rolling mill and perform final rolling to make the inner diameter dimension 85% - 90% of the outer diameter dimension, and make a high-cylinder thin-wall ring part;

[0008] Use wire cutting to cut along the axial direction of the high-cylinder thin-wall ring part to obtain two semi-ring parts, and then heat the semi-ring parts to 250°C - 350°C and straighten them under a forging hammer to obtain two bar forgings.

[0009] The final forging temperatures of the four steps of upsetting, punching, expanding with a mandrel, and ring rolling are all ≥750°C. When the temperature < 750°C, it needs to be reheated to 850°C and then the next operation is carried out.

[0010] The superalloy is GH4169 alloy.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] In the rolling method of the superalloy bar forgings of the present invention, by adopting the ring rolling method to make the forgings into high-cylinder thin-wall ring forgings and then shearing and straightening them into bar forgings, defects such as uneven thickness of the forgings, poor tissue uniformity, and multiple forging heats are effectively avoided, the quality of the forgings is improved, and the production efficiency is improved.

[0013] After inspection, the external dimensions of the forging are complete.

[0014] After inspection, the tissue uniformity of the forging is good.

[0015] After testing the room temperature tensile properties of the forging, its tensile strength is 1420 MPa - 1430 MPa (greater than the design requirement of 1275 MPa), the yield strength at an elongation of 0.2% is 1280 MPa - 1290 MPa (greater than the design requirement of 1035 MPa), the elongation after fracture is 18% - 25% (greater than the design requirement of 12%), and the reduction of area is 33% - 36% (greater than the design requirement of 15%).

[0016] The above test results show that all performance indicators of the forging meet the requirements. Specific Embodiments

[0017] To implement the rolling method of the superalloy bar forgings of the present invention, equipment such as a forging heating furnace, a press, a ring rolling mill, and a manipulator need to be provided. The following takes the superalloy with the material number GH4169 as an example to specifically illustrate the implementation manner of the present invention:

[0018] The chemical composition (weight percentage) of this GH4169 alloy is: C content ≤ 0.08%, Cr content 17.0% - 21.0%, Ni content 50.0% - 55.0%, Co content ≤ 1.0%, Mo content 2.80% - 3.30%, Al content 0.30% - 0.70%, Ti content 0.75% - 1.15%, Nb content 4.75% - 5.50%, B content ≤ 0.006%, Mg content ≤ 0.01%, Mn content ≤ 0.35%, Si content ≤ 0.35%, P content ≤ 0.015%, S content ≤ 0.015%, Cu content ≤ 0.30%, Ca content ≤ 0.01%, Pb content ≤ 0.0005%, Se content ≤ 0.0003%, and the balance is Fe.

[0019] The steps of this method are as follows:

[0020] Heat the superalloy bar cut according to specifications to 980 °C and hold for [effective thickness] × 8 min / 10 mm; perform forging modification by three times of upsetting, drawing out, and rolling, and air cool after forging; the final forging temperature is greater than or equal to 880 °C;

[0021] Reheat the forged blank to 850 °C and hold for [effective thickness] × 8 min / 10 mm; then upset to obtain a solid cylinder; then punch the solid cylinder to obtain a hollow cylinder, and the inner diameter size of the hollow cylinder is 30% - 40% of the outer diameter size;

[0022] Expand the inner diameter of the hollow cylinder to 60% - 65% of the outer diameter by using a mandrel expander; then put it on a ring rolling mill and perform final rolling to make the inner diameter size 85% - 90% of the outer diameter, so as to make a high - cylinder thin - wall ring part;

[0023] Use wire cutting to cut along the axial direction of the high - cylinder thin - wall ring part to obtain two semi - ring parts, and then heat the semi - ring parts to 250 °C - 350 °C and straighten them under a forging hammer to obtain two bar - shaped forgings.

[0024] The final forging temperature of the four steps of upsetting, punching, mandrel expanding, and ring rolling is all ≥ 750 °C. When the temperature < 750 °C, it is necessary to reheat to 850 °C and then perform the next operation.

Claims

1. A rolling method for a superalloy bar forging, characterized in that, It includes the following steps: Heat the superalloy bar cut according to specifications to 980 °C and hold for [effective thickness] × 8 min / 10 mm; Perform forging modification by three times of upsetting, drawing out and rolling round, and air cool after forging; the final forging temperature is greater than or equal to 880 °C; Reheat the forged blank to 850 °C and hold for [effective thickness] × 8 min / 10 mm; then perform upsetting to obtain a solid cylinder; then punch the solid cylinder to obtain a hollow cylinder, and the inner diameter size of the hollow cylinder is 30% - 40% of the outer diameter size; Expand the inner diameter of the hollow cylinder to 60% - 65% of the outer diameter by using a mandrel; then put it on a ring rolling mill and perform final rolling to make the inner diameter size 85% - 90% of the outer diameter to form a high - cylinder thin - walled ring part; Use wire cutting to cut along the axial direction of the high - cylinder thin - walled ring part to obtain two semi - ring parts, and then heat the semi - ring parts to 250 °C - 350 °C and straighten them under a forging hammer to obtain two bar - shaped forgings.

2. The rolling method of the superalloy bar forging according to claim 1, characterized in that, The superalloy is GH4169 alloy.

3. The rolling method of the superalloy bar forgings according to claim 1 or 2, characterized in that The final forging temperature of the four steps of upsetting, punching, mandrel expanding and ring rolling is all ≥750 °C. When the temperature < 750 °C, it needs to be reheated to 850 °C and then perform the next operation.