Continuous Rolling Mill Research Articles

Equations for control and interlinkage of multi-motor electric drive and technology in continuous rolling mills

Equations for control and interlinkage of multi-motor electric drive and technology in continuous rolling mills

Lubricating Arrangements for a Blooming and Slabbing and a Wide‐Strip Mill

The equipment described is installed in a new rolling‐mill plant of August‐Thyssen‐Hütte, in the Ruhr. The realisation that the smooth running of a modern, continuous rolling mill depends very greatly on the efficient lubrication of all bearings and gears has led to the extensive, automatic, closed‐circuit, forced‐lubrication systems of the kind now to be described.

ロール用合成樹脂軸受に就て

Bakelised roll neck bearings manufactured by the Yawata Steel Works are called NITTELITE roll neck bearing and of a special synthetic composition. They are used in several rolling mills at Yawata Steel Works, showing such excellent results, as follows.(1) On a cold roll for tin plate in which the whole series of stands had been fitted with NITTELITE bearings, the saving of power was 79%.(2) On an 18tn. continuous rolling mill, the power saving was 27%, and the life of the bearings, when compared with that of the Babbit, increased from 10, 000t to 60, 000t(3) On a wire rod mill the installation of NITTELITE bearings increased the bearing life to 1·6times and the power saving was 13%.Further, other advantages, the methods for lubrication and the setting up of NIITELITE bearings are described in the present article.

Speed transients of D-C rolling mill motors

In its introductory part, this paper explains why the transient speed changes of d-c motors under suddenly applied loads may affect the quality of the product rolled on a continuous rolling mill. In a later section, the paper analyzes the behavior of such motors driving a tandem tube mill, and points out the difference between the transient and the steady-state speed-load characteristics; the former greatly affects the product, while the latter, or the conventional speed regulation, is of only minor importance. The paper outlines the course to follow in choosing the most suitable motors and gives a mathematical study of the transient speed-load changes.

Speed Transients of D-C Rolling Mil Motors

In its introductory part, this paper explains why the transient speed changes of d-c motors under suddenly applied loads may affect the quality of the product rolled on a continuous rolling mill. In a later section, the paper analyzes the behavior of such motors driving a tandem tube mill, and points out the difference between the transient and the steady-state speed-load characteristics; the former greatly affects the product, while the latter, or the conventional speed regulation, is of only minor importance. The paper outlines the course to follow in choosing the most suitable motors and gives a mathematical study of the transient speed-load changes.

Electrically driven reversing rolling mills

The load conditions under which motors driving continuous running rolling mills operate is generally understood, and the advantage to be obtained by using a suitably designed flywheel is well known. Owing to the rapidly fluctuating load, some system of energy storage capable of performing a large amount of work for short periods must obviously be of considerable value not only from the standpoint of motor operation but also from that of power supply. Several papers have been read before this Institute dealing with the question of the action of flywheels with such loads and the advantage has been clearly demonstrated. The value of flywheels can be best appreciated when used with mills with very high and short peak loads, such as a blooming mill, where loads up to 10,000 h.p. for one or two seconds are not infrequent. The antithesis of this type of mill is the reversing mill where every effort is made to reduce the flywheel effect to a minimum so that the accelerating force required may be kept within reasonable limits. Most engineers connected with industrial work are familiar with the development of electrically driven continuous running mills but the development of the reversing mill is not generally appreciated except by those more or less connected with their design and operation. The object of this paper is to briefly review some of the more important points in its design and operation.

Electrically Driven Reversing Rolling Mills

The load conditions under which motors driving continuous running rolling mills operate is generally understood, and the advantage to be obtained by using a suitably designed flywheel is well known. Owing to the rapidly fluctuating load, some system of energy storage capable of performing a large amount of work for short periods must obviously be of considerable value not only from the standpoint of motor operation but also from that of power supply. Several papers have been read before this Institute dealing with the question of the action of flywheels with such loads and the advantage has been clearly demonstrated. The value of flywheels can be best appreciated when used with mills with very high and short peak loads, such as a blooming mill, where loads up to 10,000 h.p. for one or two seconds are not infrequent. The antithesis of this type of mill is the reversing mill where every effort is made to reduce the flywheel effect to a minimum so that the accelerating force required may be kept within reasonable limits. Most engineers connected with industrial work are familiar with the development of electrically driven continuous running mills but the development of the reversing mill is not generally appreciated except by those more or less connected with their design and operation. The object of this paper is to briefly review some of the more important points in its design and operation.