GB/T 35082-2018Steel cold extrusion part—Technical specification (English PDF)

Foreword

This Standard is drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This Standard specifies the technical specification of steel cold extrusion part (hereafter known as "cold extrusion part" for short), including the classification of deformation modes, the determination of process plans, and principles for the development of deformation processes, the determination of main process parameters, the preparation of blanks, and for equipment selection. This Standard applies to steel cold extrusion parts.

2 Normative references

The following documents are indispensable for the application of this document. For the dated references, only the versions with the dates indicated are applicable to this document. For the undated references, the latest version (including all the amendments) are applicable to this document.

GB/T 700 Carbon structural steels

GB/T 1591 High strength low alloy structural steels

GB/T 8541 Terminology of forging and stamping

3 Terms and definitions

The terms and definitions defined in GB/T 8541 apply to this document.

4 Symbols

The following symbols apply to this document.

d0 - The diameter of cold extrusion part blank, in millimeters (mm).

d1 - The outer diameter of the extrusion part of forward extrusion part, the inner diameter of backward extrusion part, in millimeters (mm).

F0 - The cross-sectional area of cold extrusion part before deformation, in square millimeters (mm²).

F1 - The cross-sectional area of cold extrusion part after deformation, in square millimeters (mm²).

h0 - The height of cold extrusion part blank, in millimeters (mm).

L1 - The depth of cup-shaped backward extrusion part hole, in millimeters (mm).

P - Extrusion force, in kilonewtons (kN).

p - Unit extrusion force, in megapascals (MPa).

S - The wall thickness of cold extrusion part, in millimeters (mm).

t - The bottom thickness of cold extrusion part, in millimeters (mm).

alpha - The inlet angle of forward extrusion female die, in degrees (°).

beta - The cone angle of backward extrusion male die, in degrees (°).

epsilonF - Section reduction rate, epsilonF = (F0 - F1)/F0 × 100%.

[epsilonF] - Allowable deformation degree.

Note: The above symbols are shown in Figure 1.

Appendix A (Informative) Example of determining cold extrusion deformation force by using nomogram

A.1 The material is 10# steel. The blank diameter d0=75 mm. The diameter after extrusion d1=45 mm. The blank height h0=112 mm. The inlet angle of female die alpha=100°. USE nomogram to determine the unit extrusion force and extrusion force for solid part under cold forward extrusion.

SEE Figure A.1. Starting from the diameter d0 of male die, FIND the intersection of d0 and the curve representing the diameter d1 after extrusion in zone 1, and PROJECT upward to find the section reduction rate epsilonF=63%. PROJECT upward by epsilonF=63% to the curve corresponding to 10# steel in zone 2, and then PROJECT onto the curve of h0/d0=1.5 in zone 3. Then CORRECT it according to the inlet angle alpha=100° of forward extrusion female die in zone 3, it can be found the corrected unit extrusion force p=1030 MPa. The point of p=1030 MPa is projected into zone 4, intersecting the projection of d0 in zone 4, and the extrusion force P=4400 kN is obtained. […]