A Method for Continuously Rolling Small Size Bars with 200 Large Section Billets

Abstract

The invention discloses a method for manufacturing small-specification bars by continuously rolling a 200 mm*200 mm large-section square billet. The method comprises the step of heating, specifically,the 200 mm*200 mm large-section square billet is heated to 1100 DEG C and subjected to soaking heat preservation; the step of disengagement rough rolling, specifically, the 200 mm*200 mm large-section square billet subjected to heat preservation is sequentially conveyed to a first rough rolling mill and a second rough rolling mill which are alternatively horizontally and vertically arranged for disengagement rough rolling, and a 165 mm*162 mm square billet is obtained; the step of intermediate finish rolling, specifically, the 165 mm*162 mm square billet enters a third rough rolling mill viaa roller way, and is rolled through six passes of rough rolling mills which are alternatively horizontally and vertically arranged, eight to twelve passes of intermediate rolling mills and eight to twelve passes of finish rolling mills, and thus small-specification bars with the diameter being 16-40 mm are obtained; and the step of shearing and cooling, after rolling is completed, the small-specification bars are subjected to multiple-length sectioning through flying shears as well as cooling, and thus the finished small-specification bars are obtained. The method has the characteristics of high operation rate, stable rolling, low rolling damage and high yield.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular relates to a method for continuously rolling small-sized bars with 200 large-section billets with high operating rate, stable rolling, low rolling loss and high yield. Background technique [0002] Iron and steel materials will remain important structural materials in the future due to their characteristics, high strength and toughness, easy processing and formability, and green recyclability. Small bars have always been the steel species with the largest consumption in my country. At present, wire bars account for about 50% of the total steel output, while small bars account for about 25% of the total steel output. With the development of automobile manufacturing, electrical machinery, and shipbuilding industries, the proportion of plates and pipes in steel will gradually increase, and the proportion of wire rods will decline, but its absolute value is still rising. [0...

AI Technical Summary

Problems solved by technology

[0003] Small-sized bars are obtained from large-section billets through multi-pass rolling. However, in the existing technology, due to the limitations of the scale, quantity and technology of rolling mills, secondary heat rolling is often required when large-section billets are rolled into small-sized bars. It can be completed, not only the heating energy consumption is high, but also the metal yield is low

At present, one-shot rolling is a widely used process, but the billet sections of conventional bar products mainly include 150mm×150mm, 165mm×165mm, and 170mm×170mm sections, and the billets with large sections above 200 square meters have conventional specifications for rolling. The bar is mainly divided into two or more rolled small-section billets by using rolls or other equipment to longitudinally divide the large-section billet into two or more small-section billets through the slitting and rolling process, thereby reducing the elongation coefficient to 1 / 2, 1 / 3 or 1 / 4, although it can reduce the elongation coefficient and reduce the types of steel billet specifications, it also has the problems of high energy consumption, low metal recovery rate, frequent equipment impact, and high shutdown operation rate

Due to the limitations of equipment and technology, the rolling of 200mm×200mm large-section billets is mainly used for rolling large bars or profile products above Ф60mm, and is rarely used for rolling small-sized products, especially for 200mm×200mm×9m ~12m billets with a larger unit weight are basically not available for rolling small-size products

In the prior art, in the rolling of small-size bars from large-section billets of 200mm×200mm, a long process is generally used to overcome the problem that the total elongation coefficient from large-section billets to small-size bars is large, but too long a process will cause rolling For a long time, the temperature difference between the head and the tail of the rolled piece in the front and rear rolling mills is large, and it is necessary to install a heat preservation cover or a secondary heating method to solve the problem of temperature drop. It will also cause the old problems of high heating energy consumption and low metal yield

In addition, the long flow pass system used in the prior art is difficult to share with sections such as 150mm×150mm, 165mm×165mm and 170mm×170mm. There are many types of spare parts such as sanitary devices, which occupy a large amount, consume a lot of money, take up a lot of funds, labor intensity is high, management and operation are difficult, and it is easy to cause confusion; and when changing types, the amount of changing rolls is large and the time is long, which makes the production rate low. , which affects the flexibility of product variety replacement, poor production and market adaptability, and seriously hampers the advantages of high production capacity of large-section continuous rolling

Images