Some standard content:
Mechanical Industry Standard of the People's Republic of China
Principles for the Preparation of Spinning Parts Process
Subject Content and Scope of Application
JB/T7532
This standard specifies the process plan for the forming of spun parts, the preparation of process regulations, the determination of roughness and the selection of equipment. This standard applies to the forming process of thin-walled metal and hollow rotating body spun parts. 2 General principles for the selection and preparation of spinning processes 2.1 The spun parts designed according to the product drawings are technically feasible. 2.2 The use of spinning forming methods should be economical and reasonable. 2.3 The pressure forming method can solve the workpieces that are difficult to form or impossible to form by other processing methods. 94
2.4 The geometric accuracy of the spun ring-shaped workpiece is good. Compared with other processing methods, its performance is significantly improved and the processing environment is improved.
The personnel engaged in the preparation of spinning processes should be familiar with the principles of spinning processing, mold design and spinning equipment. 2.5
3 Determination of spinning process plan
3.1 Spinning products can be divided into two categories according to their forming characteristics: ordinary spinning and thinning spinning (power spinning). 3.1.1 Ordinary spinning can be used for deep drawing, diameter expansion, diameter reduction, curling and other processing (see Figure 1). Thinning spinning can be divided into two categories: tapered thinning spinning (shear spinning) and cylindrical thinning spinning (flow spinning) (see Figure 2) 3.1.2
& Drawing
b Diameter expansion
Ordinary spinning
Approved by the Ministry of Machinery Industry of the People's Republic of China on October 25, 1994 246
Implementation on October 1, 1995
Conical thinning spinning
JB/T 7532--94
Figure 2 Thinning spinning
b Cylindrical thinning spinning
3.2 The most common spinning forming is external spinning, which can be divided into forward spinning and reverse spinning according to its spinning method. Very few spun parts can also be formed by internal spinning (see Figure 3).
Forward spinning
bReverse spinning
Figure 3 Spinning method
Forward spinning: During the forming process, the flow direction of the deformed metal is the same as the longitudinal feed direction of the spinning wheel. Reverse spinning: During the forming process, the flow direction of the deformed metal is opposite to the longitudinal feed direction of the spinning wheel. Internal spinning
External spinning: When spinning the rough part of a hollow rotating body, the core mold is inside the rough part and the spinning wheel is outside the rough part. Internal spinning: When spinning the rough part of a hollow rotating body, the core mold is outside the rough part and the spinning wheel is inside the rough part. 3.3 According to the characteristics and technical requirements of the spun parts, a reasonable spinning process plan should be selected. 3.3.1
Ordinary spinning is suitable for spun parts with a changed rough part diameter and basically unchanged wall thickness. Variable seam spinning is suitable for spun parts with gradually and regularly thinning rough wall thickness and no significant change in diameter. 3.3.2
Forward spinning process is suitable for spun parts with bottom, protruding ribs on the outer surface and variable wall thickness. Reverse spinning process is suitable for processing simple parts, and a shorter core mold can be used to process long spun parts. 3.3.4
For metals that are difficult to deform and some casting materials, the use of heated spinning process can effectively improve the material's compressibility. The selection of a reasonable multi-pass spinning process can effectively prevent the bulge of the front of the spinning wheel during the spinning process and improve the quality of the spun parts. When thinning cylindrical parts during spinning, under the conditions allowed by the spinning machine, the layered staggered moment method is used for spinning, which can improve work efficiency and diameter accuracy. The distribution of the amount of pressure on the spinning wheel should make the spinning pressure on each spinning wheel similar. 4
Preparation of spinning process regulations
4.1 Commonly used spinning process documents
Drawings and technical conditions of spinning parts;
Drawings of bad materials of spinning parts;
JB/T7532—94
Drawings of molds and other auxiliary tooling for spinning process; Spinning process card (including process diagram);
Spinning process calculation and instructions;
Spinning machine tool adjustment card
4.2 Contents of preparation of spinning process regulations
Spinning The preparation of the process specification for pressed parts is centered on the spinning process, including material preparation, badging, pre-spinning heat treatment, machining, spinning, intermediate heat treatment, finished product spinning, finished product heat treatment and finishing processes. It should also be equipped with necessary inspection processes and performance tests and corresponding requirements. Design of the forming process of spun parts
5.1 Design of the forming process of spun parts. According to the selected materials and their states, the total deformation rate, pass deformation rate and heat treatment process are designed. 5.2 The design of the forming process of spun parts should ensure the performance and precision requirements of spun parts. 5.3 The selected molds and auxiliary tooling should ensure the product precision. 5.4 The spinning process strives to be simplified, and the overall economy should be considered. 6 Determination of the main spinning process parameters
In the forming process of spun parts, the main process parameters to be considered are: wall thickness reduction rate, spindle speed, feed ratio, gap between core mold and spinning wheel, spinning temperature, spinning pass specification, spinning wheel motion trajectory and spinning wheel geometry, etc. 6.1 Wall thickness reduction rate
Thinning spinning wall thickness reduction rate is calculated according to formula (1): I
Thinning rate, %;
Rough wall thickness of spinning part, mm
tr——Wall thickness of spinning part, mm;
fmax—Limit thinning rate, %;
α—Half cone angle of conical spinning part.
6.2 Limit thinning rate
6.2.1 Limit thinning rate mx is calculated according to formula (2): mnx
In the formula: max
.…Limit thinning rate of material during spinning, %; te
-Rough wall thickness of spinning part, mm;
tmin—Minimum wall thickness of spinning part during working time, mm Section shrinkage rate of material, %.
6.2.2 The limit thinning rate of common materials is shown in Table 1. 1-sinaomax
t. - tmin
Limit thinning rate uax value
6.3 Feed ratio
30CrMo
40CrNiMo
1Cr18Ni9Ti
Titanium alloy
0.65 (hot)
0.6t (hot)
JB/T 7532---94
Feed ratio is the ratio of feed speed (mm/min) to spindle speed n (r/min), see formula (3): f=v/n
In thinning spinning process: take 0.21.5; in ordinary spinning process: take 1~5.
6.4 Clearance between the core die and the rotary wheel
The clearance between the core die and the rotary wheel should generally be smaller than the wall thickness of the spun part. The difference should be determined by considering the material properties, state, structure of the machine tool and the shape of the rotary wheel used. The value is generally taken as less than 0.1.0mm of the wall thickness of the spun part. 6.5 Spinning temperature
The heating temperature of common difficult-to-deform metal materials is shown in Table 2. Table 2 Hot spinning temperature values of common difficult-to-deform metals Titanium and titanium alloys Magnesium and magnesium alloys Saw and vanadium alloys Molybdenum and niobium alloys Aluminum and molybdenum alloys Tungsten and niobium alloys Nickel-chromium stainless steel 6.6 Selection of spinning passes Heating temperature selection range 425-870 320-555 4.00-620 485-650 485-1065 700-800 700-1 050
600-~750
During thinning spinning, the pass thinning rate is generally 15%~45%, and 25%~35% is commonly used. During ordinary spinning, the pass angle contraction value is generally 7\~15°. 6.7 Motion trajectory of the rotary wheel
For ordinary spinning, most of them use the involute as the main reference trajectory, and concave, convex or linear rotation methods can also be used. 6.8 Geometric shape of the rotary wheel
The rotary wheel must not only have a high hardness and a small surface roughness R, but also have a reasonable profile, mainly including; (taking the rotary wheel for thinning spinning as an example) step height hu, forming angle αp, fillet radius, and finishing angle β. etc. (see Figure 4), the general value range is: pass thinning amount plus springback amount;
α—-- 15°~-45°;
rμ- (0. 5~1. 2)to;
-generally 3°.
Figure 4 Rolling wheel for thinning spinning of cylindrical parts
7 Determination of roughness of spun parts
7.1 All metal materials that can be formed by pressure processing methods such as extrusion, forging, drawing and rolling can be spun 219
JB/T7532-—94
7.2 The state of the material has a great influence on the spinning deformation. Most of the spun cast materials need to be started by hot spinning before cold spinning can be formed.
7.3 The roughness for indigo spinning can be prefabricated with plates, pipes and other shapes.4 The thickness of the spinning rough should be calculated according to the law of constant volume. The thickness of the spinning rough of the special-shaped part should be calculated according to the positive law [see formula (4)]: =-f,simne
武中.α-Www.bzxZ.net
the flat cone angle of the special-shaped part.
For ordinary spinning, the approximate method of the surface area of the workpiece and the rough can be used for calculation. 7.5 Determine the rough precision according to the precision of the parts of the spun product. 8 Principles for selecting spinning equipment
General requirements
The wheel seat should have sufficient axial and radial drag force; the main machine should have sufficient transmission power;
The main force-bearing parts such as the bed, spindle, wheel seat and base should have sufficient rigidity; the machine should have sufficient tightening force;
The electrical and hydraulic systems of the machine tool, especially the profiling system and the stepping system, can ensure the coordination of various actions during spinning. Certain precision requirements:
The spinning equipment should be equipped with a workpiece unloading device. 8.2 Special requirements for ordinary spinning machines:
During ordinary spinning, there should be unidirectional feeding and bidirectional reciprocating swing: a reverse thrust device should be set to prevent instability:
The machine tool should have stability under high speed and large feed rate. 8.3 Special functions of thinning spinning machines
When spinning special-shaped parts (conical parts or curved hollow parts), it can ensure constant linear speed spinning (spindle speed and part weight are proportional to the spindle speed and the feed rate is constant) (the longitudinal movement speed of the spinning wheel seat is automatically changed in proportion to the spindle speed): when spinning curved workpieces, the installation angle of the spinning wheel can be automatically adjusted with the change of the workpiece surface curve to ensure constant. h.
Additional remarks:
This standard was proposed by the National Forging Standardization Technical Committee and was drafted by the Beijing Nonferrous Metals Research Institute and the Beijing Institute of Mechanical and Electrical Engineering. The main drafters of this standard are Zhang Shunfu and Zhao Chunming.
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