SU1342540A1 - Method of hot rolling of thin strips - Google Patents

Abstract

This invention relates to rolling production. It can be used at metallurgical enterprises producing sheet metal in wide-strip hot rolling mills. The purpose of the invention is to increase the capacity of hot rolling mills and strip quality. An auxiliary material with a friction coefficient of 0.3-0.45 is applied to the area of the upper surface of the front part of the roll in front of the last stand. Due to the greater frictional force between the strip and the upper roller, as compared with the friction force between the strip and the lower roller, the front end of the strip bends down and hits the first roller of the roller table. This makes it possible to increase the filling speed, which leads to an increase in the mill productivity and quality of the lanes. 1 hp f-ly, 1 ill. S (L with 4 hO SP

Description

The invention relates to rolling production and can be used in metallurgical enterprises producing sheet steel in wide strip hot rolling mills.

The purpose of the invention is to increase productivity and improve the quality of rolled products by increasing the initial rolling speed.

The drawing shows a diagram of the implementation of the method.

At the site of the upper surface of the front end of roll 2, which has a length equal to the distance from the exit from the deforma tion center to the first roller of the roller table, auxiliary material, in particular chalk, is applied before the last stand 3. After exiting the deformation, strip 4 due to greater frictional force with the upper roller bends downwards and its front end comes into contact with the first roller of the roller table 5. Then the strip, moving along, rolls of the roller table 6, winds up onto the winder.

The positive effect of this rolling method is achieved when using an auxiliary material with a friction coefficient of metal lying in the range of 0.3-0.45 (the coefficient of friction of steel on the rolls at 830 ° C is 0.17-0.20). When using such materials, the front end of the strip is stably transported along the discharge roller table at a speed of 15–16 m / s, which makes it possible to raise the temperature of the end of the steel to 0.88 ° C to 840–850 ° C. In this case, the structure of a uniform ferrite grain 6-8 points with a uniform distribution of carbides. Hot rolled 0.8 U steel with such a structure is suitable for producing cold sheet for deep drawing. The method is carried out as follows.

An auxiliary material with a certain coefficient of friction is applied to the 2.5 m length (distance to the first roller 2.1 m) along the movement of the roll section in front of the last stand on the upper surface of the forward one.

Example 1. 10 slabs are made using an auxiliary material having a friction coefficient of metal, 27.

stable transportation of the front end of the strip up to a speed of 13 m / s. End rolling temperature. At this temperature, de

O, 8U steel formation takes place in a two-phase region, which leads to obtaining a heterogeneous ferrite structure with elongated grains. Taka

The tackle structure does not comply with GOST and does not ensure the stampability of the finished cold rolled sheet.

PRI mme R 2. 8 stripes are pierced using auxiliary material having a friction coefficient of metal k = 0.3. Threshold of steady movement of the front end of the strip along the outgoing roller table

five

0

five

m / s, the temperature of the end of rolling is 840 ° C. At this temperature, the deformation takes place in the single-phase region, as a result of which the hot-rolled sheet has a structure of uniform ferrite with a grain of 6-8 points with uniform distribution of carbides. This tackle meets the requirements of GOST and is acceptable for the production of cold-rolled sheet with high formability. However, one lane at this speed left the roller table and did not hit the winder. EXAMPLE 3 9 slabs using auxiliary: friction coefficient of metal, 45. In this case, the threshold us0

the stable transportation of the front end of the strip is 16 m / s, the temperature of the end of rolling is 850 C. At this temperature, the deformation takes place in a single-phase region, as a result of which the hot-rolled sheet has the structure of a single ferrite with a grain of 6-8 points with uniform distribution of carbides. Such a tackle complies with the requirements of GOST and is suitable for production of cold-rolled sheet with high formability.

Thus, the proposed method. The assembly ensures optimum rolling end temperature and increases mill productivity.

Formula inventions

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Claims (2)

1. The method of hot rolling thin strips, including the sequential compression of the metal in the group of finishing stands, the application of the auxiliary material on the roll and the subsequent transporting the strip, about tl and - - due to the fact that, in order to increase productivity and improve the quality of rolling by increasing the initial rolling speed, to the upper surface of the front section of the bar before the last stand is equal to the distance from s1342540. exit from the deformation zone to the roller table, the material is applied with a friction coefficient of 0.3-0.45, 2. The method according to claim 1, characterized by the fact that chalk is used as an auxiliary material. Compiled by V. Vasiliev Editor N. Rogulich Tehred L. Serdyukova Order 4545/6 Circulation 480 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5  -------------------------------------------------- --------- h - “-.-.- w -. ----- ..- -. --- .-“ - to. ---- .- “--- ---- "-., - Production and printing company, Uzhgorod, st. Project, 4 Proofreader A. T sko