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Since high-precision cold-drawn tubes have good mechanical properties and excellent economic and technical value, the cylinder barrels used in many countries are made of high-precision cold-drawn tubes. When rolling high-precision cold drawn tubes, the following points should be noted:

       1. Whether the rolling pressure is selected correctly will affect the surface roughness, size and accuracy after rolling. Generally, as the rolling force increases, the surface roughness increases.

       2. To improve the surface roughness of the workpiece, rolling processing is better. When the pre-machining roughness reaches Ra1.6, as long as the interference amount is appropriate, the roughness can reach more than Ra0.2. But when the pre-machining roughness is only Ra6.4~Ra3.2, and there are vibration and random knife marks on the machined surface, then the deeper knife marks cannot be rolled out, and the only way is to increase the interference and roll again.

       3. The material is soft, highly plastic and easy to be rolled and polished. As the plasticity decreases and the hardness increases, the deformation decreases. Generally, the rolling effect of steel and copper is better, while the effect of cast iron is worse. Malleable iron and ductile iron have better rolling effect than gray cast iron. When rolling iron castings, when the material hardness of the casting is uneven, defects on the rolled surface will be revealed. Therefore, when there are many defects on the surface of the casting and the quality is poor, the rolling process should not be used.

       4. The size of rolling interference has a great influence on surface roughness and geometric accuracy. The reasonable rolling interference is 0.027~0.036mm, and the surface roughness is small at this time. The amount of interference is affected by many factors, so the amount of interference needs to be determined by multiple tests based on specific conditions. Rolling tools usually include balls, cylindrical rollers, conical rollers, rollers, etc. However, using balls as deformation members can reduce the cost of the entire rolling tool. Moreover, the ball has high precision, high hardness, and a small contact surface with the workpiece. With a smaller rolling force and a smaller interference amount, higher pressure and smaller roughness can be obtained. Moreover, the ball has a long service life, is not easy to wear, is cheap and easy to replace.
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