Production process for four-roll planetary hot-rolled tube machine

Abstract

The invention discloses a production process for a four-roll planetary hot-rolled tube machine, and belongs to the technical field of production processes of hot-rolled steel tubes. The process is characterized by comprising the following steps of: checking a tube billet; grinding; cutting to length, and loading into a heating furnace and heating to the punching temperature; feeding into a puncher and punching; pre-punching a mandril, and feeding into the four-roll planetary hot-rolled tube machine and rolling; feeding into a stretch-reducing mill unit and reducing; cutting to length; uniformly cooling; straightening; and performing flat-head chamfering, detecting flaws and inspecting. Compared with the prior art, the process has the advantages that: (1) secondary heating is reduced, and fuel, power consumption, the heating furnace and plant area are saved; (2) the length of rolled pierced billets can reach 50 meters, so that the loss caused by cutting heads and tails is reduced, and the yield is improved; and (3) the wall thickness of rolled tubes can reach 2.3mm, so that the bottleneck that the wall thickness of the rolled tubes cannot be less than 3mm in the prior art is broken through.

Description

Technical field: [0001] The invention belongs to the technical field of production technology of hot-rolled seamless steel pipes, and in particular relates to a production technology of a four-roller planetary hot-rolled pipe unit. technical background: [0002] At present, the hot-rolled seamless steel pipes at home and abroad use the Accll-Roll two-roller mill and the Assel three-roller mill. The production process is: ① tube blank inspection and grinding → ② tube blank cut to length → ③Put the tube billet into the heating furnace and heat it to the piercing temperature→④Discharge and send it to the piercer for piercing→⑤Through the mandrel→⑥Pipe rolling in the two-roll or three-roll pipe rolling unit→⑦Send it into the heating furnace for secondary heating →⑧Cut the head on the head cutting machine→⑨Size on the sizing machine→⑩Cool on the cooling bed→ Straightening on a straightening machine→ cut tail [0003] → Chamfer→ Flaw detection → test. [0004] The disa...

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Problems solved by technology

[0004] The disadvantages in the above-mentioned pipe rolling production are: ① When the Accll-Roll pipe rolling unit rolls thin-walled pipes, the consumption of the guide plate is too large. When D / S>30, the rolling is very difficult, and it is easy to occur Accident, D-pipe diameter, S-pipe wall thickness; ②The disadvantage in the production of the Assel pipe rolling unit is that there is a shoulder after the roll bite area, and the height of the shoulder is equivalent to the amount of wall reduction. The wear is very large during the manufacturing process, and thermal fatigue cracks are densely distributed around it, which brings great difficulties to the rolling, and when D / S>30, the fine protrusions on the pipe wall are obvious, making the inner surface quality of the pipe very poor. It is difficult to meet the quality requirements of thin-walled tubes; ③There are two major bottlenecks in the production of rolled tubes in the existing technology. One is that the length of the rolled blank tube cannot exceed 35 meters, and the other is that the wall thickness of the rolled tube cannot be less than 4 mm.

[0005] In view of the above situation, the patent No. "ZL201020517121.0" and the patent titled "Four Roller Planetary Hot Rolling Pipe Mill" can effectively overcome the shortcomings of the existing technology, but the corresponding production process remains to be studied

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