JB/T 9179.8-1999 JB/T 9179.8-1999 Machining allowances and tolerances of free forgings on hydraulic presses Rings JB/T9179.8-1999 Standard download decompression password: www.bzxz.net

JB/T9179.8--1999
This standard is a revision of ZBJ32003.8~88 "Machining allowances and tolerances of open die forgings on hydraulic press—Ring". When revising
, the original text was edited, and the main technical content remained unchanged. This standard replaces ZBJ32003.8-88 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: Shanghai Heavy Machinery Plant. The main drafters of this standard: Wang Qianhe and Xie Peide. 380
1 Scope
Machinery Industry Standard of the People's Republic of China
Machining allowances and tolerances of open die forgingson hydraulic press—Ring
This standard specifies the allowances and tolerances of open die forgings on hydraulic presses—Ring. JB/T9179.8--1999
Replaces ZBJ32003.8--88
This standard is applicable to the ring forgings which are completed through the final drilling process and the part size meets the requirements of d0.5D and H≤1.2D. 2 Allowances and tolerances
The machining allowances and tolerances of ring free forgings shall comply with the requirements of Figure 1 and Table 1. 0.6a
Part height
32±11
30±10
32±11
34±11
36±12
Approved by the State Machinery Industry Bureau on 1999-06-24 Drawing 1
30±10
32±11
34±11
36±12
39±13
Part diameter D| |tt||Margin α and limit deviation
30±10
32±11
34±11
36±12
39±13
42±14
45±15
32±11
34±11
39±13| |tt||42±14
45±15
48±16
34 +:11
36±12
39±13
42±14
45±15
48±16
56±19
39±13
42±14
45±15
48± 16
52±17
56 to 19
60±20
42±14
48±:16
52±17
56±19||tt| |60 ± 20 | 48±16
52±17
56±19
60±20
64±21
68±23
74±25
JB/T 9179. 8
Table 1 (End)
Part diameter D
52±17
56±19
60±20
64±21
68±23
74±25
80±27
Allowance α and limit deviation
56±19
60±20||tt ||64±21
68±23
74±25
80±27
86±29
60±20
64±21
68±23
74±25
80±27
86±29||tt| |92±31||t t||61±21
68±23
74±25
80±27
86±29
92±31
98±33
74±25
80±27
86±29
92±31||t t||98±33|| tt||80±27
86±29
02±31
98±33
104±11
104±11110±37
3.1When the part size D≤3000mm, the forging wall thickness B=（D一d）/2＋α shall not be less than 0.054D and greater than 100mm. When the part size D>3000mm, the forging wall thickness must be equal to or greater than 165mm. 4 Application examplebzxZ.net
Calculate the size of the forging of a ring:
The size of the part is: D=2000mm, d=1500 mm, H.=250mm. The margin and limit deviation are 48mm±16mm. The basic size of the forging is:
Di=2000+482048mm(take 2050mm)
Limit deviation±16mm;
d,-1500-48×1.2=1442mm(take 1440mm)Limit deviation±19mm;
H-250+48=298mm(take 300mm)
Limit deviation±16mm.
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