GB/T 15826.4-1995 Machining allowances and tolerances for steel free forgings on hammers - Rings GB/T15826.4-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Machining allowances and tolerancesfor steel open die forgings on hammer-Rings
Subject and scope of application
This standard specifies the machining allowances and tolerances for open die forgings of the ring type. This standard applies to open die forgings of the ring type with part size 0.2(D-d)≤H≤D. 2
Allowances and tolerances
The machining allowances and tolerances for open die forgings of the ring type shall comply with the provisions of Figure 1 and Table 1. 0.56
Approved by the State Administration of Technical Supervision on December 13, 1995232
GB/T15826.4
—1995
Implementation on August 1, 1996
3 General description
GB/T 15826.4--1995
3.1 Thin-walled circular ring parts, that is, when the part size meets 40mm, the allowance and tolerance of the forging shall be appropriately increased according to the following requirements after the forging allowance and tolerance are found in the table:
For parts requiring F-grade forging accuracy, the allowance of height HI and inner diameter d shall be increased according to the allowance increment coefficient in the table, while the allowance and tolerance of outer diameter shall not be increased.
For parts requiring E-grade forging accuracy, the allowance of outer diameter D, height H and inner diameter shall be increased according to the allowance increment coefficient f in the table. b.
After the allowance is increased by the value-added coefficient, the tolerance of the forging size must also be increased, and the value-added coefficient of the tolerance is 1.2. C
The values ​​of the above-mentioned dimensions after the increase are rounded to integer mm. 3.2 Calculation example
Calculate the forging size according to the F-grade forging accuracy: a.
Assume: part size D=280mm
d=260 mm
b=8±3mm
Look up the table and get: α=14±6 mm
D-d_280-26010 mmbzxz.net
Wall thickness one
Look up the table and get: allowance value-added coefficient
H=145 mm
c=18±8 mm
Calculation: The allowance and tolerance of the outer diameter do not increase: α=14±6mm Allowance for height: b·/=8×1.4=11.2~11mm Tolerance: ±3×1.2一±3.6±4mm
Allowance for the inner diameter: c·f18×1.4=25.2~25mm Tolerance: ±8×1.2=±9.6~10mm
The obtained forging size is:
D. =(280+14)±6=294±6mm
H.-:(145+11)±4-156±4mm
ds(260--25)±10=235±10mm
Calculate the forging size according to the E-grade forging accuracy: Assume: part size D=280mm
d=260 mm
Look up the table and get: a=12±5mm
6=8±3 mm
D-d_280-260=10 mm
Look up and get: excess value-added coefficient
H=-145mm
c-12±5 mm
Calculation: outer diameter allowance: a·f=12×1.4=16.8~17mm tolerance: ±5×1.2=±6mm
Height allowance: 6, f=8×1.4=11.211mm tolerance: ±3×1.2±3.6一±4mm
Inner diameter allowance: c,/12×1.4-16.8~17mm2 tolerance: ±5×1.2㎡±6mm
The forging size is:
D,=(280+17)±6297±6 mm
H. =(145+11)±4=156±4mm
d. -(260--17)±6-243±6mm
3.3 The rest shall comply with the provisions of GB/T15826.1 "General requirements for machining allowances and tolerances of steel free forgings on hammers".
Additional notes:
GB/T15826.4—-1995
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Forging Standardization. This standard is drafted by the Shanghai Mechanical and Electrical Industry Administration and other units. The main drafters of this standard are Dong Zhusheng, Pan Baimao, Lv Xiancheng, Zhang Bingji, and Xie Huazhen. From the date of implementation of this series of standards, the original JB424986 "Machining allowances and tolerances of steel free forgings on hammers" standard will be invalid. 234
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