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CN-122007829-A - Machining process of engine shell and spinning tool clamp

CN122007829ACN 122007829 ACN122007829 ACN 122007829ACN-122007829-A

Abstract

The invention discloses a processing technology of an engine shell and a spinning tool clamp, and belongs to the technical field of engine shell manufacturing. The processing technology comprises the steps of spinning and sealing, finish turning, spinning thickening, spinning necking, spheroidizing annealing, twice thinning and spinning, stress-relief heat treatment, vacuum tempering, correction, final finish turning and the like, wherein a short core die, double-spindle synchronous rotation, axial tension suppression and forming defect are adopted, and the residual stress is eliminated and the plasticity is improved by matching with grading heat treatment. The spinning tool comprises a short core die, a sealing cover, an extension rod and a switching disc, wherein the short core die is spliced by sector blocks, a center shaft of a circular truncated cone is positioned, and the disassembly and the assembly are convenient. The invention solves the problems of high cost, multiple defects, large residual stress and low precision of the traditional ultra-long core mould, realizes the high-precision, low-stress and high-efficiency forming of the shell, and is suitable for the large-scale manufacturing of the ultra-high strength steel thin-wall engine shell.

Inventors

  • LUO XIANGLING

Assignees

  • 浙江华旋特种装备有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. The processing technology of the engine shell is characterized by comprising the following steps of: S1, spinning and sealing, namely heating, spinning and closing the left end of a pipe blank workpiece (20) to preliminarily form the pneumatic shape of the head of a combustion chamber; S2, finish turning, namely turning the left end of the closed tube blank workpiece (20) to form an end face process thread boss and a shoulder, and finish turning the inner surface in place to meet the requirement of an assembly interface; S3, spinning thickening, namely accumulating materials at the tail part of the right end of the tube blank workpiece (20) by controlling metal flow to form a thick wall ring, so as to prepare for the subsequent necking forming of a thick bottom; S4, spinning necking, namely heating and necking the tail of the right end of the thickened tube blank workpiece (20) to shrink the diameter to the designed size, and primarily forming the tail end enclosure profile; s5, finish turning, namely finish machining the right end of the pipe blank workpiece (20) after necking to obtain a tail inner profile and necessary process threads; S6, spheroidizing annealing heat treatment, namely eliminating internal residual stress generated by hot spinning and rough machining in the earlier stage of a tube blank workpiece (20), stabilizing material structure, improving hardness reduction plasticity, reducing cold working deformation cracking tendency and preparing for follow-up precision thinning spinning; S7, thinning and spinning, namely, performing first wall thickness thinning and axial extension on a barrel section of the pipe blank workpiece (20) by using a short core mold (1), axial tension and synchronous rotation technology to realize main body size forming; s8, finish turning, namely removing redundant process allowance of the tail part of the tube blank workpiece (20) due to metal flow accumulation after thinning and spinning, and normalizing the appearance of the tube blank workpiece (20); s9, performing heat treatment for stress relief, namely eliminating work hardening and internal stress of the tube blank workpiece (20) caused by thinning and spinning again, recovering the plasticity of the material, and creating conditions for final thinning and forming; s10, thinning and spinning, namely performing final pass thinning and spinning, and accurately processing the wall thickness, the length and the roundness of the tube blank workpiece (20) to the final size specified by the product pattern; S11, vacuum tempering, namely hanging a tube blank workpiece (20) into a vacuum quenching furnace for heat treatment strengthening, and ensuring that the strength of a final delivered product meets the technical requirements; S12, correcting, namely, correcting the deformation after heat treatment, and firstly, correcting and straightening to ensure the subsequent machining precision of the tube blank workpiece (20); s13, finish turning, namely final finish machining is carried out, and process threads and connecting seats at two ends of a tube blank workpiece (20) are cut off, so that all the external dimensions are finished, and a finished product delivery state is achieved.
  2. 2. The process for machining the engine shell according to claim 1, wherein the spinning sealing is completed by adopting a numerical control double-spinning-wheel cold/hot powerful spinning machine for hot spinning, and the left end of the tube blank is heated and closed to form the pneumatic shape of the head.
  3. 3. The process for machining the engine shell according to claim 1, wherein in the spinning thickening, a powerful spinning and hot spinning composite process is adopted, metal is controlled to be piled up to form a thick wall ring towards the tail part of the right end of the tube blank workpiece (20), and the spinning thickening and spinning necking are completed by one-time machine feeding.
  4. 4. The processing technology of the engine shell according to claim 1, wherein the tube blank workpiece (20) is made of D406A steel, the spheroidizing annealing heat treatment is carried out on the D406A steel according to the technological specifications that the furnace temperature is less than 200 ℃, the furnace is charged, the temperature is kept for 4-4.5 h after being heated to 800-850 ℃, and the furnace is cooled to 700-750 ℃ and is discharged for air cooling after being kept for 12-12.5 h.
  5. 5. The processing technology of the engine shell according to claim 1, wherein the first thinning spinning and the second thinning spinning adopt numerical control double-spindle four-spinning-wheel nine-axis tension powerful spinning machines, and the length of a used short core mold (1) is 100-500 mm, so that the traditional ultra-long integral core mold is replaced.
  6. 6. The process for machining the engine housing according to claim 5, wherein during the thinning and spinning process, both ends of the tube blank workpiece (20) are synchronously rotated at the same speed by double spindles, and axial tension and thrust are applied to suppress defects of circumferential accumulation, bending, bulging and expanding.
  7. 7. The process for machining an engine housing according to claim 1, wherein the heat treatment destressing process is performed by furnace cooling after heat preservation for 2 hours at 580 ℃ to eliminate work hardening and internal stress of the thinned spinning.
  8. 8. The process for machining an engine housing according to claim 1, wherein the correction is a hydraulic press correction with displacement sensor and servo control system, and the correction is a vibration aging homogenization residual stress.
  9. 9. The spinning tool clamp for the engine shell, which is applied to the machining process according to any one of claims 1-8, is characterized by comprising a disc-shaped short core mold (1), a sealing cover (2), an extension rod (3) and a rotating disc (4), wherein a mounting hole (41) which is fixed with the outer end face of the extension rod (3) through a bolt is formed in the rotating disc (4), an annular groove (42) is formed in the rotating disc (4), a protruding central shaft (43) is formed in the center of the rotating disc (4), the short core mold (1) is provided with a central hole (11) and is sleeved on the central shaft (43), the outer end of the central shaft (43) is in threaded connection with the sealing cover (2), the sealing cover (2) abuts against the outer end face of the short core mold (1), the inner end of the short core mold (1) is provided with a protruding edge (12) which is embedded in the annular groove (42), the short core mold (1) is formed by splicing 3-6 equal-radian fan-shaped blocks (13), one side of each fan-shaped block (13) is provided with a protruding insert (14), and the other side of each fan-shaped block (13) is provided with a groove (15) for embedding the insert (14) of the adjacent fan-shaped block (13).
  10. 10. The spinning tool clamp for the engine shell according to claim 9, wherein the central shaft (43) is in a truncated cone shape, and the central hole (11) of the short core die (1) is tightly attached to the central shaft (43).

Description

Machining process of engine shell and spinning tool clamp Technical Field The invention belongs to the technical field of engine shell manufacturing, and relates to a processing technology of an engine shell and a spinning tool clamp. Background The large-size combustion chamber shell is a core bearing component of an aerospace engine system, and the traditional manufacturing generally adopts a sectional processing and assembly welding process route, namely, respectively machining an end socket, a bottom seal and a cylinder, and forming after assembly welding, heat treatment and nondestructive inspection. The process has the following inherent drawbacks: 1. the material utilization rate is extremely low, the end socket/back cover is formed by forging machine, the material utilization rate is only about 10%, and the raw material cost is high; 2. the welding seam is a structurally weak area, so that defects such as air holes, inclusions, unfused and the like are easy to generate, the welding heat affected zone is softened, the straightness and roundness are reduced due to welding deformation, and the structural strength and the fatigue life are reduced; 3. the large die forging die and the overlength integral core die are matched, so that the die is difficult to manufacture, high in cost and long in trial production period; 4. the process is long, the circulation links are many, the production period is long, the management cost is high, and the development requirements of small batches and multiple varieties are difficult to adapt. At present, with the continuous improvement of the spinning technology, in order to improve the strength of the shell, a spinning forming process is adopted, welding is omitted, and the cylindrical shell is extruded and elongated through spinning. The existing spinning forming technology mostly adopts an overlength integral core mold, the tool structure has poor universality and inconvenient disassembly and assembly, the core mold processing and assembly difficulty required by a large-size shell is extremely high, the defects of circumferential stacking, bulging, diameter expansion, bending and the like are easy to occur in the spinning process, and the high-precision integral forming requirement of the large-size and overlength thin-wall combustion chamber shell can not be met. Disclosure of Invention The invention aims to overcome the defects of the traditional sectional welding process and the conventional spinning process, provides a processing process and a spinning tool clamp for an engine shell, realizes the integrated weld-free processing of a pipe blank workpiece, and solves the technical problems of low material utilization rate, weld defects, high die cost, poor dimensional accuracy and long production period. The invention aims at realizing the technical scheme that the processing technology of the engine shell is characterized by comprising the following steps of: S1, spinning and sealing, namely heating, spinning and closing the left end of a tubular pipe blank workpiece to preliminarily form the pneumatic shape of the head of the combustion chamber; S2, finish turning is carried out on the left end of the closed tube blank workpiece, an end face process thread boss and a shoulder are machined, and the inner face is finish turned in place, so that the assembling interface requirement is met; s3, spinning thickening, namely accumulating materials at the tail part of the right end of the tube blank workpiece by controlling metal flow to form a thick wall ring, so as to prepare for the subsequent necking forming of a thick bottom; S4, spinning necking, namely heating and necking the tail of the right end of the thickened tube blank workpiece to shrink the diameter to the designed size, and primarily forming the tail end enclosure profile; and in the spinning necking process, after the blank workpiece is still hot or reheated, radial pressure is applied to the thickened right end tail by utilizing a spinning roller, so that the diameter of the blank workpiece is gradually reduced to a set size in rotation, and finally the geometric shape of the tail end enclosure of the combustion chamber is formed. The process needs to accurately control the reduction and the path of the spinning wheel, ensures that the material flows uniformly in the necking process, and avoids wrinkling or stacking. S5, finish turning, namely finish machining the right end of the tube blank workpiece after necking to obtain a tail inner profile and necessary process threads; Finish machining is carried out on the right end face after spinning and necking, and the main machining content is a tail inner molded surface and necessary process threads. The process aims at removing possible tiny irregular allowance after necking, regulating tail geometry and establishing reliable clamping and positioning references for subsequent processes. S6, spheroidizing annealing heat treatment, namely eliminating inter