Features of the main technological and design parameters of the stationary stand-up stand for providing a non-forced cold pipe reduction process

Abstract

Korol R. M. Features of the main technological and design parameters of the stationary stand-up stand for providing a non-forced cold pipe reduction process // Herald of the DSEA. – 2019. – № 2 (46). – P. 59–63.

The method of cold pipe reduction on HPP mills is used in the manufacture of pipes with particularly high accuracy in wall thickness, outer and inner diameters, as well as in the manufacture of particularly thick-walled pipes using the “joint” method. The drawbacks of the working stands of the KPTR mill include the fact that the stroke length of the movable separator, in which the part blank is deformed, is less than the stroke length of the working stand, as well as the moving parts of the stand, are heavy, which, in turn, limits the rolling speed, reducing the very productivity of the mill. The movable cage of the working cage has low rigidity, which causes a significant amount of elastic deformation of the “working tool - rolling cage” system. This is confirmed by the calculations given in the work. Using the stationary stand of the KPTR mill with supporting rollers to reduce particularly thin-walled pipes at the initial moment of rolling the front end of the pipe can lead to its constant flattening due to the large weight of the supporting rollers and working rollers, thus violating the stability of the rolling process. The disadvantages of the cage should be attributed, and the complexity of manufacturing support rollers. The aim of the work is to determine the technological and structural features of the stationary stand of the KPTR mill to ensure a non-forced cold pipe reduction process. To ensure the above, it was proposed to eliminate support rollers from the stand design and ensure free rolling of the rollers on the working cone, to carry out the so-called non-forced rolling process - as the separator moves, the rollers are rotated by friction forces in the deformation zone, and their trunnions freely roll over the calibrated working surface support bars. The use of a stationary stand of the KPTR mill with a roller with rolling elements makes it possible to achieve stability of the rolling process during cold reduction of thin-walled tubes, and in the manufacture of single-walled tubes using the “joint” method, ensure high surface quality and long-term durability of the working tool due to non-forced rolling process.