Some precautions for rolling pipe rolling
Some precautions for rolling pipe rolling
(1) The material is soft, highly plastic and easy to be rolled and polished. As the plasticity decreases and the hardness increases, the amount of deformation decreases. Generally, rolling of steel and copper is better, while that of cast iron is worse. Malleable iron, ductile iron rolls better than gray cast iron. When rolling iron castings, when the material hardness of the castings is uneven, defects on the rolled surface (pores, blisters, etc.) will be exposed. Therefore, when there are many defects on the surface of the casting and the quality is poor, the rolling process should not be used. The size of rolling interference has a great influence on surface roughness and geometric accuracy.
(2) Whether the rolling pressure is selected correctly will have an impact on the surface roughness, size and accuracy after rolling. In general, as the rolling force increases, the surface roughness increases. But when the rolling force increases to some extent, the surface roughness does not continue to increase. If it continues to increase, the rolling surface will begin to deteriorate and cracks will appear. To increase the surface roughness of the workpiece, it is better to use rolling processing. 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 vibrating and random knife marks on the machined surface, then the deeper knife marks cannot be rolled smooth, and the only way is to increase the interference and roll again. If the ovality and taper of the hole are too large, the above defects will still exist after rolling, and the roughness will be large. Therefore, the pre-processed surface should be as small as Ra3.2 as much as possible to obtain small roughness and ideal accuracy.
(3) The rolling speed has little effect on the surface roughness, so we can increase the rolling speed to increase production efficiency. The number of rolling times should not be too many. The feed amount should be determined according to the diameter of the ball. The smaller the feed, the smaller the surface roughness. The feed amount should be determined through testing. 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 is easy to replace.
Please indicate the source when reprinting:http://www.czbqyy.com
(1) The material is soft, highly plastic and easy to be rolled and polished. As the plasticity decreases and the hardness increases, the amount of deformation decreases. Generally, rolling of steel and copper is better, while that of cast iron is worse. Malleable iron, ductile iron rolls better than gray cast iron. When rolling iron castings, when the material hardness of the castings is uneven, defects on the rolled surface (pores, blisters, etc.) will be exposed. Therefore, when there are many defects on the surface of the casting and the quality is poor, the rolling process should not be used. The size of rolling interference has a great influence on surface roughness and geometric accuracy.
(2) Whether the rolling pressure is selected correctly will have an impact on the surface roughness, size and accuracy after rolling. In general, as the rolling force increases, the surface roughness increases. But when the rolling force increases to some extent, the surface roughness does not continue to increase. If it continues to increase, the rolling surface will begin to deteriorate and cracks will appear. To increase the surface roughness of the workpiece, it is better to use rolling processing. 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 vibrating and random knife marks on the machined surface, then the deeper knife marks cannot be rolled smooth, and the only way is to increase the interference and roll again. If the ovality and taper of the hole are too large, the above defects will still exist after rolling, and the roughness will be large. Therefore, the pre-processed surface should be as small as Ra3.2 as much as possible to obtain small roughness and ideal accuracy.
(3) The rolling speed has little effect on the surface roughness, so we can increase the rolling speed to increase production efficiency. The number of rolling times should not be too many. The feed amount should be determined according to the diameter of the ball. The smaller the feed, the smaller the surface roughness. The feed amount should be determined through testing. 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 is easy to replace.
Please indicate the source when reprinting:http://www.czbqyy.com