GB/T 15826.5-1995 Machining allowances and tolerances of steel free forgings on hammers Sleeves GB/T15826.5-1995 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-Seamless cylinder hushings
1 Subject content and scope of application
This standard specifies the machining allowances and tolerances for sleeve type open die forgings. GB/T15826.5--1995
This standard applies to parts with dimensions conforming to D0.5D sleeve free forgings. 2 Allowance and tolerance
The machining allowance and tolerance of sleeve free forgings shall comply with the requirements of Figure 1 and Table 1. pg-d
Approved by the State Bureau of Technical Supervision on December 13, 19950.56
Implemented on August 1, 1996
GB/T15826.5
815218
181912
ttetgt
0291018-9
5391 /01 ]8.9]
110120167280221802
866281
6138861
F21517512106140156291 76888882+287818
01988669
18816201283219881919
3 General description
GB/T15826.5-1995
3.1 For thin-walled sleeve parts, that is, when the wall thickness of the parts meets the requirements of ≤40 mm, the allowance and tolerance of the forgings shall be appropriately increased according to the following requirements after the allowance and tolerance are found in the table:
a: For parts requiring F-grade forging accuracy, the allowance of height H and inner diameter d shall be increased according to the allowance increment coefficient f in the table, while the allowance and tolerance of outer diameter D shall not be increased.
b. For parts requiring E-grade forging accuracy, the allowance of outer diameter D, height H and inner diameter d shall be increased according to the allowance increment coefficient in the table. The tolerance of the forging size after the allowance is increased by the value-added coefficient must also be increased, and the value-added coefficient of the tolerance is 1.3. The values ​​after the above-mentioned dimensions are increased are rounded to integer mm. 3.2 The rest should comply with the provisions of GB/T15826.1 "General Requirements for Machining Allowances and Tolerances of Steel Free Forgings on Hammers". 3.3 Calculation Example
a. Calculate the forging size according to the F-grade forging accuracy: Assume: part size 2D=280 mmd=260 mm2H=380 mm2 Look up the table to get: a=19±8mmb-20±8mmc=25±11mmD-d_280--260
=10 mm
Look up the table and get: the allowance increment coefficient F=1.6
Calculation: the allowance and tolerance of the outer diameter do not increase: α=19±8mm Height allowance: 6·f-20×1.6=32mm Tolerance: ±8×1.3=±10.4～±10mm Inner diameter allowance: c?f=25×1.6=40mm Tolerance: ±11×1.3=±14.3～±14mm The forging size is:
D, (280+19)±8-299±8mm
H. (380+32)±10=412±10mm
d.=(260--40)±14=220±14 mm
b. Calculate the forging size according to the E-grade forging accuracy parts: Assume that the part size
D-280 mm
Look up the table and get: α=17±7 mm
Wall thickness=D=d_280-260
d-260 mm
6=20±8 mm
2=10mm
Look up the table and get: Allowance value-added coefficient f=1.5www.bzxz.net
H = 380 mm
c=17±7mm
Calculation: Outer diameter allowance: a·f17×1.5=25.5=26mmTolerance: ±7×1.3=±9.1～±9mm
Height allowance: h.f20×1.5=30mm
Tolerance: ±8×1.3=±10.4～±10mmInner diameter allowance: c·f=17×1.5=25.5～26mmTolerance: ±7×1.3=±9.1～±9mm
The obtained forging size is:
D=(280+26)±9-306±9 mm
H.(380+30)±10=410±10mm
d(260-26)±9=234±9mm
Additional remarks:
GB/T15826.5
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 was drafted by 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 JB4249-86 "Machining Allowances and Tolerances of Hammer Steel Free Forgings" standard will be invalid. 238
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