DE4126069A1 - Rolling process for steel rod and bars in rolling mills - in which rolling strand passes twice through first rolling sections consisting of rolling sections and blocks - Google Patents

Abstract

In a rolling process for steel rod and bars in smaller capacity rolling mills and using heavy starting billets, the rolling strands is passed twice through the first rolling section of a rolling mill consisting of continuous rolling sections and blocks. After the first pass, the strand is returned via thermally insulated channels (7) with the aid of drivers (8) and is reheated in furnace (1) prior to its second pass through the first rolling section (4). USE/ADVANTAGE - Used in steel rod and bar mills and enables heavy starting billets to be used for rolling mills of smaller output, saving the use of one reheat furnace and one rolling section and shear.

Description

On wire and fine steel rolling mills with low output 100 t / h sets the corresponding to the smaller hourly output necessary low final rolling speed of the Finished rolled goods the continuous rolling process Limits because according to the law of Volume constancy of the rolling stock in the individual passes Piercing speed in the first roll stand is too low turns out. This is all the more true the larger the cross section the insert stick is dimensioned. From the Practice is known to have the first stitches in an open Rolling on trios or a reversing duo with free The rolling stock is run out after each pass will. It is also known to use high reduction machines for this purpose (Steel and iron (108/1988) 1 p. 31-36) be used. However, with all methods it is disadvantageous that the mass of the stick by the Outlet length of the rolled material after the first pass is limited. A spout length that is too large would, besides the required space, also for high heat losses of the rolling strand when it is fed into the next one Lead continuous rolling scale. Avoiding heat loss by using a reheating oven it is possible but disadvantageous in terms of economy and investment.

The invention specified in claims 1 to 5 lies based on the problem on rolling mills with an hourly output Use sticks with high mass.

The invention provides a reheating furnace, a rolling mill and saved a pair of scissors.  

The invention is based on an exemplary embodiment are explained in more detail. In the drawing it is represented method according to the invention.

The billets 2 heated to the rolling temperature in the furnace 1 are fed on roller tables 3 to a continuously arranged rolling stack 4 , the first rolling stand of which is arranged as close as possible to the furnace in order to keep heat losses of the billet 2 low. In addition, the tapping is supported by the driver 5 in front of the first roll stand.

The exchange of the billet 2 on the roller stack 4 is carried out in the usual way, ie the billet 2 is reduced in cross-section in several passes, so that z. B. with an initial cross-section of 150 mm and an initial length of 6 m behind the last rolling stand of the rolling mill results in a cross-section of ⌀ 70 mm with a length of 36 m. After the tip has been cropped, this roll strand is returned by means of the scissors 6 in heat-insulated troughs 7 and drivers 8 , specifically through the furnace 1 for tapping in the roll stack 4 . The rolling of the roll strand is carried out at the final rolling speed of the last roll stand of the rolling stack 4 . The tapping in the first roll stand takes place with a changed tapping speed compared to the first revolution. The rolling mill 4 is automatically set to another speed frequency before the tapping, which corresponds to the optimal decreases in the stretching range of the second pass. The tapping speed in the first roll stand is determined by the final speed in the finishing mill block or the finishing mill scale. The second pass is rolled on a second track of the rolling mill 4 , accordingly, in the rolling season 4 , rolling is carried out on two tracks but only with one core. After the second pass of the rolling strand through the rolling stack 4 , the further rolling on the rolling stack 9 takes place in a continuous flow without a free outlet after the tip of the rolling strand has been scooped again on the scissors 6 .

In the process, it advantageously appears that the heat losses occurring despite the heat-insulated channel 7 are fed back during the transfer in the oven 1 which is present anyway, and an additional reheating oven is thus avoided.

Furthermore, the two passes of the rolling train save a complete rolling mill with the same number of roll stands as the first rolling mill 4 compared to a conventional fully continuous rolling mill. In addition, another scissor system with scrap loading is saved by the double cropping and the possible emergency cut of the roll strand on the scissors 6 .

Claims (5)

1. A method for rolling wire and fine steel on rolling mills of lower power and high billet mass, characterized in that the first rolling mill ( 4 ) of a rolling mill consisting of continuous rolling mills and blocks is run through twice by one and the same rolling train. 2. The method according to claim 1, characterized in that the rolling strand is guided in thermally insulated channels ( 7 ) with the aid of drivers ( 8 ). 3. The method according to claims 1 and 2, characterized in that the transferred roll strand passes through the furnace ( 1 ) for reheating in the first roll stand ( 4 ) before it is tapped again. 4. The method according to claims 1, 2 and 3, characterized in that the first rolling stack ( 4 ) and the scissors ( 6 ) are set to a different speed sequence each time the roll train is run through again. 5. The method according to claims 1, 2, 3 and 4, characterized in that the scissors ( 6 ) behind the first rolling mill ( 4 ) is designed for two wires and scoops the tip of the rolling strand with each pass and performs emergency cuts if necessary.