Machining method for multi-slotted lining

A slotted bushing and processing method technology, which is applied in the field of hole extrusion enhanced precision machining, can solve the problems of insignificant increase in the fatigue strength of the extruded workpiece, high cost of the hole extrusion strengthening process, and great influence of the residual stress of the hole wall. , to achieve the effects of not easy plastic deformation, wide applicability, and small deformation during heat treatment

Pending Publication Date: 2021-11-05
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Purpose of the invention: For hard materials with multiple slits and thick bushes, it is difficult to make multi-slit bushes by roll-bending method; single-slotted thin-walled bushes are easily deformed during the extrusion strengthening process, and the bushes cannot Repeated use, after extrusion strengthening, the raised ridge height at the slit is large, the amount of reaming is large, and the residual stress formed on the hole wall is greatly affected, which leads to high cost of the hole extrusion strengthening process and increased fatigue strength of the extruded workpiece Not obvious

Method used

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  • Machining method for multi-slotted lining
  • Machining method for multi-slotted lining
  • Machining method for multi-slotted lining

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] A method for processing a multi-slit bush, comprising the following steps:

[0035] (1) Select the multi-slit bushing material as 0Cr17Ni7Al;

[0036] (2) Blanking the 0Cr17Ni7Al bar based on the structural parameters of the extruded workpiece;

[0037] (3) Roughly process the blanked 0Cr17Ni7Al bar according to the design size of the multi-slit bushing;

[0038](4) Use the TH565 heat treatment system to heat-treat the rough-machined bar;

[0039] (5) The 0Cr17Ni7Al bar after heat treatment is drilled and formed into a bush;

[0040] (6) The bushing is grooved to form a multi-slit bushing.

[0041] figure 1 It is a schematic diagram of the structure of the four-slit bush obtained in Example 1 of the present invention. The tail part 1 of the multi-slit bush is connected with the hole extrusion strengthening fixture. Close the slit of the front end 3, reduce the diameter of the front end 3, and make the outer diameter of the multi-slit bush smaller than the diameter ...

Embodiment 2

[0043] Embodiment 2 The investigation of heat treatment mode

[0044] There are three typical heat treatment systems for 0Cr17Ni7Al materials: TH565, RH510, and CH480. The effects of different heat treatment methods on material properties are as follows:

[0045] ①The heat treatment system of TH565 is: 1050℃, water or air cooling +760℃×90min / air cooling to ≤15℃+565℃×90min, air cooling. After TH565 heat treatment system heat treatment, the material HRC is 38~43, σ b is 1370MPa, σ 0.2 It is 1280MPa, and the elongation is 9%.

[0046] ②RH510 heat treatment system: 1050℃, water or air cooling +950℃×10~30min, air cooling+(-73℃)×4~8h cold treatment +510℃×30~60min, air cooling. After heat treatment of RH510 heat treatment system, the HRC of the material is 44~48, σ b is 1620MPa, σ 0.2 It is 1510MPa, and the elongation is 6%.

[0047] ③ CH480 heat treatment system: 1050°C, water or air cooling + cold rolling or cold drawing (about 60% deformation) + 480°C × 60min, air cooling. ...

Embodiment 3

[0050] Since the following formula exists in the hole extrusion strengthening process:

[0051] D+2t=D 0 +Ea=D 0 (1+E r ),in,

[0052] D is the diameter of the working ring of the extrusion mandrel;

[0053] D. 0 is the diameter of the initial hole of the extruded workpiece;

[0054] t is the bushing thickness;

[0055] E. r is the relative extrusion amount;

[0056] The nominal aperture is 16 / 32in, 1in=25.4mm, and the nominal aperture is 16 / 32in=12.7mm, that is, the final hole diameter is 12.7mm. With the diameter of the final hole being 12.7mm, the relative extrusion amount E r 5%, the diameter of the initial hole of the extruded workpiece D 0 Taking 12.12mm as an example, use the measurement method to explore the slot width of the multi-slit bushing.

[0057] Initial hole diameter D 0 12.12mm, the relative extrusion amount E r is 5%, then D+2t is 12.73mm.

[0058] When the diameter D of the working ring of the extrusion mandrel is 10mm, the thickness t of the ...

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Abstract

The invention provides a machining method for a multi-slit lining. The machining method comprises the following steps of: (1) selecting a material 0Cr17Ni7Al used for preparing the multi-slit lining; (2) conducting blanking on ta e 0Cr17Ni7Al bar based on structural parameters of an extruded workpiece; (3) conducting rough machining on the blanked 0Cr17Ni7Al bar with reference to the design size of the multi-slotted lining; (4) conducting heat treatment on the roughly machined bar by using a TH565 heat treatment system; (5) drilling the 0Cr17Ni7Al bar subjected to heat treatment to form the lining; and (6) grooving the lining to form the multi-slotted lining. The machining method is high in production efficiency and machining precision and can improve the surface quality of the wall of an assembly hole of the extruded workpiece and the fatigue performance of the extruded workpiece.

Description

technical field [0001] The invention discloses a multi-slit bushing processing method, which belongs to the technical field of hole extrusion strengthening and precision machining, and in particular relates to a multi-slit bushing processing method which can improve hole extrusion strengthening of typical structural parts of large wide-body passenger aircraft. Background technique [0002] Extrusion strengthening of the assembly hole of the extruded workpiece by using a slotted bushing is a relatively advanced hole extrusion strengthening technology in the current aircraft manufacturing industry. This technology can form a uniform residual stress field on the wall of the assembly hole of the extruded workpiece. Therefore, the fatigue strength of the extruded workpiece can be improved, the fatigue gain can be increased, and the fatigue life of the extruded workpiece can be prolonged. [0003] The slotted bushing used in hole extrusion strengthening technology is generally man...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23P15/00
CPCB23P15/00
Inventor 苏宏华刘飞陈玉荣梁勇楠丁文锋徐九华傅玉灿陈燕杨长勇赵彪
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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