This invention relates to apparatus to provide tandem rolling mill arrangements wherein the relative disposition of one rolling mill stand relative to another is independently and readily changeable to orientate the rotational axes of the rolls, hence the roll pass design, relative to a given passline. More particularly, the present invention relates to an improved construction for separate and independent rolling mill stands and to pedestal means for the support of such mill stands at preselected locations and inclined relationships to provide a desired tandem arrangement of rolling mill stands.
A tandem arrangement of rolling mill stands is defined for the purpose of this invention to mean a plurality of mill stands supported and arranged so that during the rolling process a workpiece will progress from one stand to the next along a continuous straight path. The features and advantages of the present invention are particularly useful for numerous tandem arrangements forming continuous jobbing-type mill trains including universal mill trains for rolling metallic workpieces to produce products commonly referred to in the art as flats, rebars, angles, channels, round and squares. Modern high-speed and high-production bar mills incorporate massive and specially designed individual mill stands arranged to form a continuous mill train with alternate mill stands providing horizontally-and vertically-arranged rolls to alleviate the necessity for twisting the bar or workpiece between adjacent mill stands. When it is necessary to twist the bar between mill stands, guides are specially designed for this purpose but they have inherent disadvantages including marking of the bar or other forms of workpieces. The guides represent a substantial and added expense for each mill stand and the guides must be periodically replaced due to different roll pass designs and due to wear of the guiding surfaces. In the standard horizontal-vertical continuous mill arrangement, the horizontal mill stands are driven by heavy-duty drives that are independently supported at spaced locations from the mill stands and the vertical mill stands are coupled to a separate drive usually located within a pit below the mill stand itself or on a massive steel structure above the mill. There are still other numerous forms of rolling mill arrangements particularly, for example, in regard to the rolling of smaller workpieces such as rods wherein the mill stands are arranged at a 45.degree. angle to the horizontal with adjacent mill stands being offset at 90.degree. to each other. This mill arrangement permits the rolling of rod using roll passes without the need to twist the rod between pairs of rolls. Variations to this arrangement of rolls for a rod mill cannot be provided since the arbors for the rolls are rotatably carried by a single rigid structure and it is not possible to alter or change the disposition of one pair of rolls in a given mill stand with respect to another pair of rolls in a different mill stand.
These tandem or otherwise continuous arrangements of rolling mills are typically used in steel producing facilities where high tonnage output from the mills is expected and where the product produced by a tandem mill does not change to any great extent on a day-to-day basis. Such mill arrangements are not, however, suitable for continuous jobbing-type mill trains where a variable rolling schedule demands consecutive passes to be provided by rolls with their rotational axes angularly disposed at 90.degree. to each other but in different angular relations to the horizontal. In other words, a given rolling schedule may require that the mill stands are disposed at alternate vertical sides of a given passline and that each mill stand forms an angle of 45.degree. to the horizontal. The next rolling schedule will require a tandem mill train, for example, wherein a given rolling mill stand has the rotational axes of its rolls arranged parallel to the horizontal while the next succeeding rolling mill stand has the rotational axes of its rolls arranged vertically or perpendicular to the horizontal. In the jobing mill type of tandem mill trains, there are other instances which render it desirable, if not necessary, that the rolls in the mill stands have their rotational axes disposed at different angles other than as just described. For example, for special products, a rolling sechedule may provide that a first mill stand has the rotational axes of its rolls arranged at an angle of 30.degree. to the horizontal and then the next succeeding rolling mill stand has the rotational axes of its rolls arranged at an angle of 60.degree. to the horizontal. Other considerations, together with rolling schedules, may render it necessary to arrange all the mill stands at one vertical side of the passline.
The capital investment for facilities required to convert one tandem mill arrangement into another and the time needed to accomplish the change are important factors that affect the production costs of the rolling mill facility. Thus, it becomes highly desirable to not only provide apparatus which is versatile in its use but also designed for providing such facilities at a minimum of capital investment so as to be economically feasible to produce rolled products at low tonnage volumes.
USPTO Backgrounds
USPTO Backgrounds