JB/T 9179.4-1999 JB/T 9179.4-1999 Machining allowances and tolerances of free forgings on hydraulic presses Discs and punchings JB/T9179.4-1999 Standard download decompression password: www.bzxz.net

JB/T9179.4—1999
This standard is a revision of ZBJ32003.4—88 "Machining allowances and tolerances of free forgings on hydraulic presses". During the revision, the original text was edited and the main technical contents were modified as follows: the allowance coefficient is determined by the tonnage of the hydraulic press. This standard replaces ZBJ32003.4—88 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Forging Standardization. The responsible drafting unit of this standard is Shanghai Heavy Machinery Plant. The main drafters of this standard are Wang Qianhe and Xie Peide. 370
Discs and punchings".
Machinery Industry Standard of the People's Republic of China
Machining allowances and tolerances of open die forgings on hydraulic press--Disk and punched hole
Machining allowances and tolerances of open die forgings on hydraulic press--Disk and punched holeThis standard specifies the allowances and tolerances of open die forgings on hydraulic pressJB/T 9179. 4- 1999
Replaces 2.13J32003.488
This standard is applicable to self-forgings of disks and punched holes without holes with part size relationship H.≤1.0D and d≤0.5D. 2 Allowances and tolerances
The machining allowances and tolerances of disks and punched holes shall comply with the requirements of Figure 1 and Tables 1 and 2. fo
1(0. 4~~0. 5)a
Part height
17±619±6
23±825±8
Approved by the State Bureau of Machinery Industry on 1999-06-24400
23±8258
(0. 4 ~0. 5)
Part diameter D or side length
(0. 4--0. 5)c
10001250
Allowance α and limit deviation
27±929±1031
29+1031+10
27±929±1031±1033±
850~2 2002 60
35012 200
±14/45+15/49±16
37±1241±14.45±1549±1653±1857=1529±10|31±10
±1137±1241=1445±1549±1653±18 57196120/65±22033-
371241144511514911653±1857-.1961±201631226 942319/61+:2065±22/69±237324
45+15/49+1653+18/57
+1961±2065+2269+2373+2177-26200001-01 Implementation
Part aperture d
Punch diameter dnwww.bzxz.net
Part aperture d
Punch diameter d.
General provisions
3.1 The punch of forgings shall be determined according to Table 2.
JB/T9179.4-1999
3.2 The limit diameter of the hole of the punching part is calculated according to formula (1) and formula (2): 142
dmax = 0. 37D + 6
dmin = 0. 208 H + 33
Wherein: D--forged diameter before punching, mm;
H-forged height before punching, mm
3.3 When the size ratio of the disc without hole D/H ≥ 4, the forging is allowed to have a drum shape. 210
Beijing Electric Core
3.4 ​​The workpiece is finally finished on a 8000~16000kN hydraulic press, D and H in Figure 1. The single-sided allowance coefficient of ~A is taken as 0.4. The workpiece is finally finished on a hydraulic press above 25000kN, D and H in Figure 1. , the single-sided margin coefficient of A is 0.5.
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