Two-stand angularly hot rolling minor diameter seamless steel tube rolling technique and equipment thereof

Abstract

The invention discloses the rolling technology of a double-stander oblique hot rolling small diameter seamless steel tube, and the rolling technology of the invention is that a mandrel trolley pushes a mandrel into a pierced billet and is pushed to move forward, the mandrel is heated to 950 DEG C to 1150 DEG C by an intermediate frequency induction heating electric furnace, the mandrel trolley continues to pushes the heating pierced billet into a rolling mill to carry out wall increasing and diameter reducing rolling, only the mandrel and a roller are cooled during rolling process; the pierced billet that breaks away from the mandrel is placed into a reheating electric furnace for heating to 950 DEG C to 1150 DEG C and is sent into a stretch reducing and wall increasing rolling mill to carries out the diameter reducing rolling, the heating while rolling can be realized, and only the roller is cooled during the rolling process; the invention is finished by cooling, straightening, cutting and online detecting after rolling. The invention realizes the technology of heating the mandrel and the roller while rolling and cooling by improving the heating method of a heating furnace, structure and the cooling method of the mandrel and the roller. The rolling technology of a double-stander oblique hot rolling small diameter seamless steel tub improves efficiency, simplifies the technology, reduces cost, saves energy and reduces pollution, thus the rolled steel tube is high in precision.

Description

Technical field [0001] The invention belongs to the technical field of steel pipe rolling equipment and rolling process, and mainly relates to a two-stand obliquely hot-rolled small-diameter seamless steel pipe rolling process and equipment. Especially suitable for the production of high-precision small-diameter thick-walled seamless steel pipes. Background technique [0002] Small-diameter seamless steel pipes are used in many fields such as production and life. At present, the production of small-diameter seamless steel pipes is mainly made by cold drawing (rolling). In the production process, there are many times of heading, cold drawing and pickling; and the production of small-diameter seamless steel pipes has many processes, high costs, and serious pollution. There is a lot of waste, and there are problems of slow efficiency, high energy consumption, low yield, serious pollution, and high environmental pressure. In addition to the deformation resistance of the steel materia...

AI Technical Summary

Problems solved by technology

The problems that this process exists mainly include: 1. Rolling after heating will cause a large temperature difference between the first rolled end of the steel pipe and the rear rolled end (especially when watering the cooling roll while rolling, the temperature of the cooling roll At the same time, the water will flow to the steel pipe being rolled, and it will also cool the steel pipe being rolled, causing the steel pipe to cool down faster), and the internal stress difference of the steel pipe is also large. The wall thickness is uneven, and a sizing machine is required for sizing and wall uniformity; the process is complicated and cumbersome

2. During the rolling process, the cooling roller will cool the steel pipe being rolled at the same time, so that the cooling speed of the steel pipe is too fast, and the rolled steel pipe cannot be greatly reduced in diameter and wall; in order to meet the required diameter reduction and wall reduction requirements, it is necessary to carry out many times rolling

Multi-stand rolling has high energy consumption, large equipment investment and high cost

4. The existing oblique roll hot rolling equipment can only increase the wall and reduce the diameter without mandrel rolling, but cannot reduce the wall and reduce the diameter

And no mandrel is added during rolling, the inner wall is rough, the finish is poor, the precision is low, and the tolerance is large

Larger diameter seamless steel pipes can still be used if the tolerance is larger. For small diameter seamless steel pipes, if the tolerance is large, they cannot meet the requirements of the market, and the produced seamless steel pipes are not practical.

[0004] Because the rolls of existing rolling equipment are mostly solid structures, this roll can only cool the outside when cooling, and also cool the rolled steel pipe while cooling the outside of the roll, thereby reducing The temperature of the rolled steel pipe causes a large difference in the internal stress of the steel pipe, and the outer diameter, inner diameter, and wall thickness of the two ends of the rolled steel pipe are not uniform, and a sizing machine is required for sizing and uniform wall, which not only increases the rolling cost , and increase equipment investment, increase complex and cumbersome rolling process

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