This standard specifies the machining allowances and tolerances of single-turn crankshaft and eccentric shaft free forgings. This standard applies to single-turn crankshaft and eccentric shaft forgings with a crank height H (or D) ≤ 500mm and a crank length L ≤ 600mm. GB/T 15826.8-1995 Machining allowances and tolerances for hammer-on steel free forgings Single-turn crankshaft GB/T15826.8-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Machining allowances and tolerancesfor steel open dieforgings on hammer-Single throw crankshaft
Subject content and scope of application
This standard specifies the machining allowances and tolerances for open dieforgings of single throw crankshafts and eccentric shafts. GB/T15826.8...1995
This standard applies to single throw crankshafts and eccentric shaft forgings with a crank height H (or D) ≤ 500mm and a crank length L ≤ 600mm. 2 Allowances and tolerances
The machining allowances and tolerances for single throw crankshafts and eccentric shaft forgings shall comply with the provisions of Figure 1 and Table 1. 0.5t
Approved by the State Administration of Technical Supervision on December 13, 1995 248
Implemented on August 1, 1996
Registered turn lengthwww.bzxz.net
General description
GB/T 15826.8
Machining allowance and tolerance of single-turn shaft forgings crank height H (or D)
14±6/1818
Adding residual base 6, h, and limit deviation
16-72119
12±1818±823
Forging accuracy grade F
1016±2020±826±1
1152±23
20-826
1152-±:2322±929
22929±1358±2623±:1030-
358± 2623-1030± 1360- 27
1360±2725-1133±156630
25+1133-
1566+3027 -1235+1670-30
Forging accuracy grade E
15+6/20+
+840+1817+7
5+1150+
1150+22
927+1254±2422+929+
21±927±1254±2422
929±1358±2624±1031
462-27
241031±1462:.2726+11341568t303.1
The machining allowance and tolerance of the crank part are determined according to the height H (or D) and length L of the crank. 3.2 The machining allowance and tolerance of the cylindrical part (journal, shaft tail and flange) shall be determined according to the maximum diameter D and the total length L of the part. α According to G13/T15826.7 "Mechanical machining allowance and tolerance of steel free forgings on hammer-type step shafts", the step shaft forgings shall be increased by 20%. 3.3 Whether the step and concave are forged or not shall be determined according to Appendix A of GB/T15826.7. 3.4 Whether the flange is forged or not shall be determined according to Appendix B of GB/T15826.7. 3.5 The rest shall comply with the provisions of GB/T15826.1 "Mechanical machining allowance and tolerance of steel free forgings on hammer-general requirements". Additional remarks:
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 Forging Standardization Technical Committee. This standard is drafted by the Shanghai Mechanical and Electrical Industry Administration and other units. The 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 "Mechanical T-allowance and Tolerance of Hammer 1 Steel Free Forgings" standard will be invalid.
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