特级西西人体444www高清大胆,99久久久无码国产精品不卡,蜜臀AV无码精品人妻色欲,一本色道久久综合亚洲精品不卡

What are the requirements for raw materials in cold heading machines

1. The chemical composition and mechanical properties of the raw materials used for cold heading in the cold heading machine should comply with the relevant standards for multi station automatic cold heading machines.

2. The raw material must undergo spheroidization annealing treatment, and its metallographic structure is spherical pearlite level 4-6.

3. In order to minimize the tendency of cracking and improve the service life of the mold, the hardness of the raw materials needs to be as low as possible for the cold drawn materials to increase plasticity. Generally, the hardness of raw materials is required to be between HB110 and 170 (HRB62-88).

4. The dimensional accuracy of cold drawn materials should generally be determined according to the specific requirements and process conditions of the product. Multi station cold heading machines generally have lower requirements for the precision of reduced diameter and strong reduction dimensions.

5. The surface quality of cold drawn materials requires a lubricating film with a dull dark color, and the surface must not have defects such as scratches, folds, cracks, burrs, rust, oxide scales, pits, and pitting.

6. It is required that the total thickness of the decarburization layer in the radial direction of the cold drawn material should not exceed 1-1.5% of the diameter of the raw material (the specific situation depends on the requirements of each manufacturer).

To ensure the cutting quality during cold forming, it is required that the cold drawn material has a hard surface and a soft core.

8. Cold drawn materials should undergo cold forging tests. Wenzhou cold heading machines also require materials to have lower sensitivity to cold work hardening, in order to reduce the increase in deformation resistance caused by cold work hardening during the deformation process.