CN1026868C

CN1026868C - A Precision Forming Method for Thin-walled Cylindrical Parts

Info

Publication number: CN1026868C
Application number: CN 92103837
Authority: CN
Inventors: 于德弘; 邢光汉
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 1992-05-30
Filing date: 1992-05-30
Publication date: 1994-12-07
Anticipated expiration: 2007-05-30
Also published as: CN1069685A

Abstract

A precision forming method of a thin-wall cylindrical part belongs to the field of metal processing. It features that hot rolled seamless steel pipe is used as blank and the unique expanding and extruding-drawing composite forming technology is used to complete the machining with less cutting and no cutting. The invention provides a novel processing method with low material consumption, high efficiency and high quality for the production of thin-wall cylindrical parts with the length of less than 2 meters. The invention is used for processing the submersible motor shell, can save materials by 25-40%, improves the production efficiency by 3-8 times, ensures the primary dimensional precision and form and position tolerance of the product to meet the original design requirements, and obviously improves the internal quality of the product and the surface quality of the shell.

Description

A method of precisely forming thin-wall tube-shaped element

The invention belongs to the metal manufacture field, be specifically related to the precision machined new method of a kind of thin-walled cartridge type spare.

The difficulty of processing of the thin-wall tube-shaped element that thin-walled cartridge type spare, especially draw ratio are big is higher.The processing method that adopts has two kinds at present, and first kind is turning, promptly processes on lathe.Its major defect is that efficient is low, and stock utilization is low, the more important thing is that dimensional accuracy and form and position tolerance are difficult to guarantee that the wall thickness difference is big, percent defective height, and the more difficult processing of rough surface.Second method is a bore hole, promptly processes on special boring mill, and except that productivity ratio and precision slightly improved, other problems existed equally, and equipment investment is big.

Such part can adopt flow forming and molding process processing, this method to have to save material, boost productivity and dimensional accuracy than advantages such as height.But spinning process can not directly use hot seamless tube, and the residual stress of product is big to the required precision height of blank, and equipment investment is big, specification requirement is high, and critical technological point is many, the processing cost height.

Also can adopt new technology processing such as forward extrusion or backward extrusion in addition.But cold extrusion equipment needed thereby tonnage is big, die cost height, required precision height, and the life-span is short.And can't stablize the assurance machining accuracy.And conventional ironing technology not only can't be used for tubing processing, and precision is lower.

Purpose of the present invention: provide a kind of and have low material consumption, high efficiency, high-quality, low percent defective, and the novel processing method of thin-wall tube-shaped element simple to operate.

Technological process of the present invention is:

Pipe blanking-conventional surface treatment (pickling, phosphatization, saponification)-preformed (type rises)-final shaping unit (formed by extrusion and tension)-side cut.

The invention will be further described below in conjunction with accompanying drawing.

Fig. 1 is the frock schematic diagram of the embodiment of the invention.

Fig. 2 is the stairstepping punch structure schematic diagram of the embodiment of the invention.

Fig. 3 is the structural representation of the die I of the embodiment of the invention.

Fig. 4 is the structural representation of the die II of the embodiment of the invention.

Fig. 5 is the submersible motor shell structure schematic diagram of the embodiment of the invention.

Implement when of the present invention, adopt hot rolled seamless steel tube to do blank, its external diameter is identical with the product external diameter or smaller, and wall thickness equals the thickest+0.5mm～1mm of product, and the length of pipe is pressed 102%～104% conversion of product weight.With the submersible motor housing shown in the accompanying drawing 5 is example, and the weight of product is respectively 4.6kg～9.12kg, and the pipe length that is converted into is respectively: 250mm～470mm.Carry out conventional surface treatment (pickling, phosphatization, saponification) subsequently, use the stairstepping punch (2) with special shape to pipe (1) bulging (preformed) then, the pipe after the bulging (1) is pressed into together with punch (2) to squeeze in the mould of being made up of die I (4), die II (5), unloading block (7), discharging circle (8), guide cylinder (9) and draws composite molding (final shaping unit).Punch (2) is descending, and after pipe (1) was all by unloading block (7), the press backhaul was unloaded the workpiece of forming by unloading block (7).

In order to guarantee finishing smoothly and dimensional accuracy of products of moulding, except implementing according to above-mentioned specific process, the shape and the parameter of punch (2), die I (4) and die II (5) all need particular design.The shape of stairstepping punch (2) and parameter as shown in Figure 2, wherein the major diameter D of punch equals product internal diameter+0.05～0.10mm, end diameter d equals pipe internal diameter+0.5～0.7mm, the transition angle α of two steps is 60 °.Punch total length L and small end length L ₁, determine that general total length L equals product length and trimming allowance and the length sum that enters die cavity according to the product length of different size.The shape of die I (4) as shown in Figure 3, going into modular angle α (4) is 9 °～12 °, inner diameter d (4) determines that according to deformation extent the deformation extent of this work step accounts for 70～75% of total deformation degree usually.The shape of die II (5) as shown in Figure 4, going into modular angle α (5) is 7 °～8 °, die inner diameter d (5) is the poor of product spare external diameter and t * 4%, t is a pipe thickness.

The present invention compared with prior art, major advantage is: the hot seamless tube dimensions scope of employing is bigger, and outer surface quality and dimension precision requirement are not high; The stock utilization height, production efficiency height, good product quality; Moulds of industrial equipment are simple, long service life, and also easy to maintenance; Can adopt Universal hydraulic press (or through repacking) to produce, and equipment tonnage is little, operating maintenance is convenient. Be specially adapted to length less than the processing of 2 meters thin-wall tube-shaped element.

Claims

1, a kind of method of precisely forming of thin-walled cartridge type spare is characterized in that: the technological process of this method is: pipe blanking-conventional surface treatment (pickling, phosphatization, saponification)-preformed (bulging)-final shaping unit (formed by extrusion and tension)-side cut.

2, the method for precisely forming of thin-wall tube-shaped element as claimed in claim 1, it is characterized in that: described pipe blanking is to adopt hot rolled seamless steel tube to do blank, the external diameter of pipe is identical with the external diameter of product or smaller, the wall thickness of pipe equals the thickest+0.5-1mm of product, and the 102-104% that the length of pipe is pressed product weight converts.

3, the method for precisely forming of thin-wall tube-shaped element as claimed in claim 1 is characterized in that: described conventional surface treatment is that pipe is carried out pickling, phosphatization, saponification surface treatment.

4, the method for precisely forming of thin-wall tube-shaped element as claimed in claim 1 is characterized in that: the described type that rises (preformed) is that the ladder punch with particular design carries out bulging to surface treated pipe.

5, the method for precisely forming of thin-walled cartridge type spare as claimed in claim 1; it is characterized in that: described formed by extrusion and tension (final shaping unit) is the pipe behind the type that rises to be pressed into together with the stairstepping punch to squeeze in the mould of being made up of die I, die II, unloading block, discharging circle, guide cylinder draw composite molding (being final shaping unit); after moulding is finished; press drives the punch backhaul, and the pipe of forming is unloaded by unloading block.

6, the method for forming as claimed in claim 1, it is characterized in that: the major diameter D of described stairstepping punch equals product internal diameter+0.05-0.10mm, end diameter d equals pipe internal diameter+0.5-0.7mm, the transition angle α of two steps is 60 °, punch total length L and small end length L1, product length according to different size determines that the total length L of general punch equals the summation that product length and trimming allowance and punch enter the length of die cavity.

7, the method for forming as claimed in claim 1, it is characterized in that: the modular angle α that goes into of described die I is 9 °-12 °, the punch inner diameter d is determined according to deformation extent, usually the deformation extent of this work step accounts for the 70-75% of total deformation degree, the modular angle α that goes into of die II is 7 °-8 °, the die inner diameter d is the poor of product external diameter and t * 4%, and t is a pipe thickness.