Determination of the moment of elastic force in the section of the drive line with a gap in the stand of the reduction mill

The definition of the moment of elastic force on the section of the drive line with a gap at a variable external rolling moment in the stand of the reduction mill is proposed. To take into account the effect of the gap, a correction factor is introduced. Keywords: stand, rolling moment, gap, elastic force moment, reduction mill, correction factor. [email protected]

EZTM experience in designing and manufacturing of rolling mill main drive gearboxes

The experience of the Electrostal Heavy Machinery Plant (EZTM) in designing and production of special gearboxes and gear stands for main drive of various rolling mills is summed up. The specifics of section and ball-rolling mills, piercing and reduction mills, mills for cold rolling of tubes and mills for the production of reinforcing bars are considered. It was shown that at designing of special gearboxes for the main drives of rolling mills, the designer, taking into account the parameters of the mill, must build a cyclogram of their loading, which depends both on the range of rolled products and on the variability of loads within the rolling cycle of one billet. In the Designing Department of EZTM, the strength calculation of gears of different types is carried out in the REDUK 4.3 software package, which allows performing strength calculations of gears taking into account the expected loading cyclogram. At the same time, the program provides the initial data for calculating the shafts and bearings, i.e, the forces in engagement and the rotational speed of each of the shafts for the first stage of the cyclogram. The geometrical parameters of the gears are optimized according to the criterion of contact and flexural strength, both between the stages and within each of them.The load sequence diagram depends both on the range of rolled products, and variable loadings in a rolling cycle of a workpiece. Geometric parameters of gears are optimized by contact and bending equal strength, as between the stages as within each of them. Carburizing, hardening and grinding of teeth are provided and secured technologically. Currently, the gearboxes manufactured by the plant are successfully operated at many metallurgical enterprises, both in Russia and abroad. Among them, the gearboxes of main drive of the piercing mill of the Seversk Pipe Plant, the mills for cold rolling of tubes in the USA and China, the section mills at the Yartsevo Casting and Rolling Plant, the reduction mill at the Dnepropetrovsk Metallurgical Plant, etc.

Formation Mechanism and Influence Factors of Roll Surface Oil Film Thickness in the Double Cold Reduction Mill

In the double cold rolling process, the emulsion entering the roll gap during the double cold rolling process has the characteristics of high concentration and small flow rate so that the roll surface oil film thickness will affect roll gap oil film thickness, which in turn affects the rolling friction coefficient. This paper analyzes the formation mechanism and evolution process of the roll surface oil film thickness by considering the equipment and process characteristics of the emulsion direct injection application lubrication system. Then, based on the principle of fluid dynamics, the roll surface oil film thickness model in the double cold rolling process is established, and the prediction of the roll surface oil film thickness during the double cold rolling process is realized. Subsequently, the effects of five factors, such as rolling speed, work roll roughness, maximum contact stress between rolls, emulsion initial dynamic viscosity, and emulsion pressure viscosity coefficient, on the roll surface oil film thickness are quantitatively analyzed, and the corresponding influence laws are given. Finally, the relevant model and software that are applied to the 1220 double cold reduction mill have achieved good results.

A calculation of the external loading is in the drive of cage of reduction figure

The calculation of external loads is proposed to determine the rolling moment depending on the time of peak load action at different steady rolling moments in the stand of the reduction mill. Keywords pipe, rolling, algorithm, calculation, stand, moment. [email protected]

The Calculating Method of Thinning Pipes Ends before Rolling in the Reduction Mill

In this article it is discussed one of the main directions of improving the rolling tubes technology on a pipe-rolling plant with a continuous mill, in order to reduce the pipe-ends cut. A method for preliminary end sections thinning modes, calculating during rolling on a continuous mill, to compensate for wall subsequent thickening in the reduction mill, has been developed. Method distinctive feature is the calculation of end thickening volume, which must be reduced by a specified quantity when end sections rolled. The sequence of technological calculations is given. The results of pipe reduction computer simulation by regular rolling modes, and modes calculated by the proposed method, are represented The analysis of the simulation results showed the possibility of thickened ends length reducing of at least 10%.

Method of Speed Mode Correction of Rolling Pipes in the Reduction Mill

The article develops one of the main directions of improving the technology of pipe rolling on a reduction-stretching mill, in order to reduce the end crop. The article describes a speed adjustment technique of the reduction mill, when rolling the front end and back end of pipes, the length of which corresponds to the length of the thickness of ends of the finished pipe. A distinctive feature of the technique is the calculation of volume of the thickness end, which must be reduced by an adjusted value, when rolling the end area in the head stands. The sequence of technological calculations and the results of industrial testing of pipe reduction by standard rolling modes, and modes calculated by the proposed technique, are given. An analysis of the results of industrial testing showed the possibility of reducing the mass of the thickness ends by no less than 7%.

The Investigation of Pipe Ends Formation under Reduction Mill Rolling

The paper presents the results of the experimental study of the longitudinal and transverse wall thickness variation at the ends of a oil-well tubing during reduction procedure. It is established that the greatest "contribution" to wall thickness data spread is made by the pipe facets, which is caused by the influence of the reduction regimes and the rolls calibration due to the metal flow into the tapers of groove. In the course of work, recommendations were also made that, in order to reduce the wall thickness variation of pipes, it is necessary to develop the calibration ensuring the decreasing of the intensity of metal flow into the tapers of groove, as well as decrease the reduction at the mill stands, and increase the coefficient of kinematic tension between the stands of the stretch-reducing mill.

Combined Setting Technology of the Bending Roll in Five Stands 4-High Reduction Cold Mill

On the foundation of taking equipment and production technology into consideration,we present a set of combined setting technology of the parameter of the strip suit to cold reduction mill of roll four and framework five。Then the parameter of the strip was controlled combined and coordinated of framework 1-5. On the one hand,it ensures the function of the force of the bending roll not cancel out mutually,and enhances the controlled effect of the force of the bending roll in the strip,on the other hand, there will not be new extra and partial shape wave under the complex effect of the force of the bending roll.Meanwhile there will not be the problem that the force of the bending roll in some parts get too high even overall loading while the other parts get get too low in the setting procedure.While improving the lifespan of the fluid cylinder, the adjusting rest of the force of the bending roll get increased. While the related technology has been adopted by field engineering, we have achieved excellent result, and there is the value for more expanding.