Detail of GB/T 21470-2008

Introduction of GB/T 21470-2008

1 Scope This standard specifies the machining allowances and tolerances for open die forgings of disks, columns, disks with holes, rings, seamless cylindrical sleeves, etc. This standard is applicable to the open die forgings of carbon steel and alloy steel with carbon content not exceeding 0.9% and the total content of other alloying constituents not exceeding 4%. The allowances and tolerances for open die forgings beyond the scope specified in this standard shall be determined by the supplier and the purchaser through negotiation. 2 Normative References The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to investigate the possibility of applying the latest editions of these documents. For undated references, the latest edition applies to this standard. GB/T 21469 Machining Allowances and Tolerances for Steel Open Die Forgings on Hammer - General Requirement JB/T 9179.4 Machining Allowance and Tolerance of Open Die Forgings on Hydraulic Press - Disk and Punched Hole JB/T 9179.5 Machining Allowance and Tolerance of Open Die Forgings on Hydraulic Press - Short Round Shaft JB/T 9179.7 Machining Allowance and Tolerance of Open Die Forgings on Hydraulic Press - Cylinder JB/T 9179.8 Machining Allowance and Tolerance of Open Die Forgings on Hydraulic Press – Ring 3 Disks and Columns 3.1 The dimensions of open die disk forgings with round, rectangular (A1/A2≤2.5) and hexagonal cross-sections shall satisfy 0.1D≤H≤D (or A1, S); the dimensions of open die column forgings with round, rectangular (A1/A2≤2.5) and hexagonal cross-sections shall satisfy D

Contents of GB/T 21470-2008

Foreword II 1 Scope 2 Normative References 3 Disks and Columns 4 Disks with Holes 5 Rings 6 Seamless Cylindrical Sleeves Annex A (Informative) Examples of Calculation of Dimensions for Open Die Ring Forgings of Rings Annex B (Informative) Examples of Calculation of Dimensions for Open Die Forgings of Seamless Cylindrical Sleeves