JB/T 9179.2-1999 JB/T 9179.2-1999 Machining allowances and tolerances of free forgings on hydraulic presses - Circular shafts, square shafts and rectangular cross-sections JB/T9179.2-1999 Standard download decompression password: www.bzxz.net

JB/T9179.2—1999
This standard is a revision of ZBJ32003.2-88 "Mechanical machining of free forgings on hydraulic presses. I. Allowances and tolerances for circular shafts, square shafts and rectangular sections
". During the revision, the original text was edited and the main technical content was modified as follows: The determination of the length allowance coefficient is determined by the tonnage of the hydraulic press. This standard replaces ZBJ32003.2-88 from the date of implementation. This standard is proposed and managed by the National Forging Standardization Technical Committee. The responsible drafting unit of this standard: Shanghai Heavy Machinery Factory. The main drafters of this standard: Wang Qianhe and Xie Peide. 361
Machinery Industry Standard of the People's Republic of China
Machining allowances and tolerances of open die forgings on hydraulic press Round shaft, square shaft and rectangular cross-section
Machining allowances and tolerances of open die forgingsJB/T 9179.2—1999
Replaces 2BJ32003.2.-88
on hydraulic press--Round shaft,square shaft and rectangular cross-sectionScope
This standard specifies the allowances and tolerances of open die forgings on hydraulic press--Round shaft,square shaft and rectangular cross-section. This standard is applicable to round shaft, square shaft and rectangular cross-section forgings with I≥1.5D (or 1.5A) and A≤B≤1.5A. 2 Allowances and tolerances
The machining allowances and tolerances of open die forgings of round shaft, square shaft and rectangular cross-section shall comply with the provisions of Figure 1 and Table 1. a15
(1-1. 5)a
(1~1. 5)a
Part length
18±620±7
Approved by the State Machinery Industry Bureau on 1999-06-24 362
Part section dimensions BA, D
Additional amount α and limit deviation
+9:30+10
10132-
28±10/3010
-10132
37-+12
13143 +. 14
Implemented on 2000-01-01
Part length
116000
16 00020 000
3 General provisions
JB/T 9179. 2 -1999
Table 1 (end)
Part section dimensions B, A, D
Additional allowance α and limit deviation
30±10/32±1134
30±1032±
32±11
11/37±12
37±1240±1343±1
13±1446±13
37±1240±1343±14/46±15
/49±16/54±18| |tt||40±13/45www.bzxz.net
4314146
1859±20
54±18|59±20
46±1549±16
54±1859±20
49±1654±18|59±20
49±1654±1859±20
3.1 When the slenderness ratio (L/A or L/D) is equal to or greater than 15, the single-sided allowance on the section is 0.6a, and when it is greater than 30, it is 0.8a. The upper and lower deviations are enlarged accordingly.
3.2 The allowance and tolerance of rectangular section forgings should be checked in the table according to the width B and length L of the parts. 3.3 The bevel angle α of the forging head should not be greater than 15°. 3.4 Determination of the length allowance coefficient:
The workpiece is finally finished on a 8000~16000kN hydraulic press, and the single-side length allowance coefficient in Figure 1 is 1.0; the workpiece is finally finished on a 25000~315000kN hydraulic press, and the single-side length allowance coefficient in Figure 1 is 1.25; the workpiece is finally finished on a 60000~~120000kN hydraulic press, and the single-side length allowance coefficient in Figure 1 is 1.5.
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