Multi-roll large-diameter thin-wall seamless pipe mill

Abstract

The invention discloses a multi-roll large-diameter thin-wall seamless pipe mill, and relates to a cold rolling large-diameter thin-wall seamless pipe mill. Mill rolls moves steadily, and a difference of linear velocities of a middle part and two ends of a concave arc roll way of each mill roll is small, so overlarge plastic deformation of pipes is avoided in the axial direction. The mill comprises a main handpiece, a seamless pipe clamping feed-in device and a mandril feed-in response device, wherein the main handpiece comprises a frame and a stand; a dog is arranged in the frame; the stand is provided with a dog driving mechanism; the dog in the frame can reciprocate relative to the stand; the dog, a seamless pipe and a mandril are concentrically arranged; the dog driving mechanism is provided with driving rods which move synchronously and have different two-stage speeds; the driving rods reciprocate along the axis direction of the dog; the dog consists of a body and a mill roll set which are concentrically arranged and can move relatively along the axis; and for the driving rods with different two-stage speeds, the high-speed driving rod is connected with the body, and the low-speed driving rod is connected with the mill roll set. The mill has steady milling process, and the finished pipes have high precision and good quality.

Description

technical field [0001] The invention relates to a seamless steel pipe rolling mill, especially a cold-rolling large-caliber thin-wall seamless steel pipe rolling mill. Background technique [0002] The processing of seamless steel pipes can be completed by hot rolling and cold rolling processes. The hot rolling process consumes a lot of energy, and the surface quality of the finished tube cannot meet the requirements for direct utilization. Some users hope that the large-diameter thin-walled seamless pipe has a certain precision, so as to reduce post-processing and reduce the production cost of users. Therefore, the cold rolling process has gradually formed, such as the Assel rolling method for the extension of thin-walled blank tubes arranged in the form of a multi-stand skew rolling mill. However, the equipment has a large model, high investment costs, and the surface quality of the finished tube Can not fully meet the needs of users. [0003] At this stage, my country'...

AI Technical Summary

Problems solved by technology

The low material utilization rate is only 40-50%; and the processing equipment is huge and expensive, the processing is difficult, the production efficiency is low, and the cost performance is low; the quality is poor and the output is small, which is far from meeting the growing market demand (high-quality, high-precision Large-diameter cold-rolled seamless steel pipe)

The fundamental reason is that there is no large-diameter (including extra-large-diameter) cold-rolled pipe mill equipment, and it is impossible to efficiently organize the production of high-precision, high-quality large-diameter cold-rolled seamless steel pipes

[0005] Large-diameter cold-rolled steel pipe equipment cannot simply be enlarged and imitated from small-scale equipment. On the one hand, it is because the development of the corresponding mechanical parts industry has not kept up with the development of the seamless steel pipe industry.

On the other hand, due to the large diameter of the large-diameter pipe, if the processing mode of the prior art is still used, the linear speed of the middle part and the two ends of the concave arc raceway of the roll will have a large difference, such as Figure 5 , 6 As shown in the figure, it is a two-roller type. Since the radius difference between the middle and both ends of the 1 / 2 roller is large, the linear velocity V5 at the middle point 84 and the linear velocity V6 at the end point 83 are at 1 / 2 roller speed. In the case of a fixed value, there will be a large difference

This difference will cause uneven plastic deformation of the pipe at the contact point with the 1 / 2 roller, resulting in problems such as pipe rupture, uneven wall thickness, or uneven density of various parts of the pipe.

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