The eccentric diameter of carbon steel is also called eccentric reducer, and the quality should meet the current national standard. The deviation should be in accordance with the provisions of table 4.2-3. The eccentric size head should not be cracked or heavy, the wall thickness should be larger than the wall thickness of the large diameter end pipe section, the roundness of the eccentric size head should not be more than 1% of the corresponding outer diameter, and the deviation should be allowed to be plus or minus 3mm; The center line of the concentric reducer should coincide, and its eccentricity should allow the deviation to be plus or minus 5mm.

The application range of stamping process is very wide. It can process metal sheet material and bar material, and can also process various non-metallic materials. The forming method of eccentric size head is to use the stamping process, and we have a clear requirement for the materials in the eccentricity head punch forming process.

1. Surface quality, the surface of the material shall be smooth and smooth, without the damage of layers and mechanical properties, without rust, oxide and other fixtures. Surface quality material, stamping is not easy to rupture, not easy to scrape the mold, the surface quality of the workpiece.

2, stamping performance, in order to help stamping deformation and improve the quality of parts, materials should be: good plasticity (high uniform elongation delta b), showed (sigma s/sigma b) and large thickness direction coefficient, plane directivity of small plate, material yield strength and elastic modulus ratio (sigma s/E).

3. Tolerance of thickness, the thickness tolerance of materials shall conform to the state standards. Because certain mold clearance is suitable for material of a certain thickness, the thickness tolerance of material is too big, not only directly affect the quality of the parts, but also can cause the damage of the mold and punching machine.