Device for adjusting wall thickness of hot rolled steel tube

Abstract

The invention provides a device for adjusting the wall thickness of a hot rolled steel tube and relates to a wall thickness adjusting device. The device comprises an electric control device and a hydraulic device controlled by the electric control device, wherein the electric control device comprises a current transformer arranged on a main motor of a rolling mill, an overcurrent relay, a time relay and an auxiliary relay; and the hydraulic device comprises a change valve and an oil cylinder. The current transformer, after being electrified, drives the overcurrent relay and the auxiliary relay to close; a control circuit is kept to normally work through an auxiliary latching contact of the auxiliary relay; and the time relay controls the working state of the change valve by controlling the auxiliary contact of the auxiliary relay. The device of the invention has the advantages of effectively reducing even eliminating uneven longitudinal wall thickness of the hot rolled steel tube, improving the quality and the yield of the steel tube, along with simple structure, easy manufacturing and control, low investment and high profit.

Description

technical field [0001] The invention relates to a wall thickness adjusting device, in particular to a wall thickness adjusting device applied in hot-rolled steel pipes. Background technique [0002] In the production of hot-rolled seamless steel pipes, the problem of uneven wall thickness of steel pipes is a very common problem, and the head and tail (both ends) of the same steel pipe, the general enterprise deviation can be controlled within ± 12.5% ​​* wall thickness, which meets the national standard The upper and lower limits of the steel pipe, that is, the head deviation reaches the upper limit of the standard, and the tail deviation reaches the lower limit of the standard. Seriously, the steel pipe will exceed the wall thickness tolerance range and become a defective product. [0003] Therefore, a large number of experiments have been done on how to solve the problem of uneven longitudinal wall thickness of hot-rolled steel pipes. In the experimental research, it is co...

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Problems solved by technology

[0008] 2. On the pipe rolling unit, during the pipe rolling process, the volume of the heat-expanding plug of the pipe rolling mill head is increasing, and its wall thickness change law is gradually thinning from the beginning to the end, which also leads to the longitudinal deviation of the steel pipe wall thickness. The temperature of the head of the capillary pipe passing through the machine is lower than that of the tail, and the deformation resistance of the head is greater than that of the tail during the rolling process, resulting in the wall thickness of the blank pipe gradually becoming thinner after rolling

[0009] In the follow-up process of the hot-rolled steel pipe, the longitudinal wall thickness deviation cannot be corrected, resulting in the longitudinal wall thickness deviation of the hot-rolled steel pipe

[0010] Such problems have plagued the production of hot-rolled seamless steel pipes for a long time, resulting in serious uneven longitudinal wall thickness, poor quality and low pass rate of hot-rolled seamless steel pipes.

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