SU1296245A1 - Method of producing zinc-coated strips - Google Patents

Abstract

The invention relates to rolling production and can be used in the training of galvanized strips. The aim of the invention is to obtain strips with a predetermined roughness. A method including rolling a billet, applying a zinc coating and training in rollers with a prepared surface, involves controlling the temperature of the coating of the strip entering the deformation zone. To do this, after coating the strip with a certain temperature, control training is carried out, determining the surface roughness of the strip leaving the deformation zone, after which the temperature of the coating entering the strip deformation zone is adjusted in accordance with the dependence T t + + 675 / RgT, (Rg-Rg), where T is the temperature of the zinc coating, is necessary to obtain a strip with the required surface roughness, & Kd is the required surface roughness emerging from the deformation zone of a strip of microns; O1z surface roughness of the rolls, microns; t ,, is the temperature of the zinc coating before control training, C; surface roughness of the strip after the control of training, microns. Thus, the method makes it possible to stabilize the microrelief of the surface of the obtained strips with a zinc coating. from s. with a joint venture

Description

112

The invention relates to rolling production and can be used in the training of galvanized strips.

The purpose of the invention is to obtain strips with a predetermined roughness.

A method that includes rolling a billet, applying a zinc coating and training in rollers with a prepared surface provides for regulating the temperature of the coating entering the strip deformation zone, which is carried out by means of test control training, determining the coating temperature of the incoming and surface roughness. coming out of the deformation zone of the strip and then regulating the temperature of the coating entering the deformation area. stripes according to dependency

T t;

de T)

to „R

ab

t.

R

ak

  (, „.

Qb

The heating temperature of the zinc coating is necessary to obtain a strip with the required surface roughness, C; the required surface roughness of the strip emerging from the deformation zone, µm;

surface roughness of the rolls, microns;

zinc coating temperature before control training. WITH; surface roughness of the strip after the control of training, microns.

The imprint of the microrelief of the rolls on the surface of the strip is determined by the ratio of the maximum pressure in the deformation zone to the yield strength of the rolled metal at the point of maximum pressure. Moreover, the greater this ratio is, the closer the microrelief of the strip surface is in its shape to the microrelief of the roll surface. A characteristic feature of galvanized strips is that when they are trained, the surface microrelief is formed as a result of the material being shaped into a relatively thin coating, and the pressure of the training is determined by the ductility of the metal base. In this case, the coefficient of

50

five

0

five

0

The printability during training will depend on the ratio of the plasticity of the substrate to the plasticity of the coating.

With an increase in this ratio, when training in rough rolls, the surface roughness of the trained strip increases, and when training in smooth rolls, it decreases.

A smooth change in the ratio of the plasticity of the base and the coating increases (decreases) the temperature of the coating.

Thus, simultaneous with the training, the temperature control of the coating of the O1C1 laminated strip entering the deformation zone allows the surface roughness of the trained bands to quickly and smoothly control, which leads to their quality.

Imprint microrelief rolls on the surface of the strip when training in rough rolls can be defined by the following expression:

P1,208 + 0,37 In P / t

Max

five-. TI ii9.5P

  b7

the coefficient of micro-relief rolls on the surface of the strip; stress ratio; R, R. - surface roughness

rolls and strip after training, microns;

maximum pressure in the deformation zone during strip training. Pa; yield strength of the strip material at the maximum pressure point. Pa.

Where

;)

Pg "V

R

WOIKC

6.0

When heated

zinc oxide

cover with

20 C to temperature t C its plasticity can be defined as

Where

 5t

% KT 520

dependent on

coefficient of temperature;

plasticity of the coating at 20 ° C, Pa.

Then, taking into account that the pressure of the dressing depends on the plasticity of the base, which remains unchanged, we can write

Р Р

maxt

rpa t I15LLia 1- P

, t to; b7,7 -R;

 0.208 + 0.37 1pp („„ ,;

. 0.208 + 0.37,

 0.208 + 0.37 ln (-%. J

one

 0.208 + 0.37 In - + 0.37 In P

Substituting the expression 0.37 Inll / - max o

From equation (1) we get

V

hell + 0.37 In- t

It was established experimentally that the expression obtained for hot galvanizing of steel strips is true

-0,004 2l-fc-2o)

K: J. t

(3)

Substituting (3) into the expression (2-) we get

 ;

 20

i + 0.37 In, 2 (-t-zo)

L OOO K Ztt-lO)

+ o, 37 In m + 0.37 lo, 00412 (t-20) Inl 20 +0.00152 t - 0.03 (4)

When the coating is heated to a temperature T, the printability coefficient is

th + 0.00152 T - 0.03.

 o, 00 52 t-0.03 -, „- - 0.00152 t + 0.03 0.00152 (T - t), (5)

R,

R

ai

Since i :: v i R;

Qb

Subtract from the expression (5) the expression for the formation, which in the process of dress- ... ch.rovki maintain unchanged. Would-

what kind of assortment is removed. that galvanized strips degree of influence. no zinc heating temperature

45 coatings before training on the surface roughness of the finished strips. For this purpose, control training is carried out, during which the temperature t of zinc is determined.

50 of the coating of the strip entering the deformation zone and the roughness Rg of the surface of the strip emerging from the deformation zone is measured. Regulate the temperature of the coating of the strip deformation entering the source according to dependence 675.

one

L-V p / - (G., - K „.) 0.00152 (1-0, оЪ

ai

T-t

one

0.00152 Rg T Qt

),

 + (R. -) .R

ab

from

(6)

Thus, to establish the heating temperature of the zinc coating T, necessary to obtain the desired surface roughness

T t, + ™ (R - R and

av:

)

At the same time, an increase in the coating temperature increases the coefficient

ax 2.0 1)

JO

f5

(2)

what's longer than 20 (3)

wasp

Ola

t-)

ati

thirty

35

strip R, it is sufficient to determine the roughness R of the strip surface formed during the task at the deformation zone of the strip with an arbitrary coating temperature t. These values can be measured in the process of control strip training when switching to a new range of bands. In this case, formula (6) takes the form:

, P (R, - R ,,), ab

where T is the heating temperature of the zinc coating, is required to obtain a strip with the required surface roughness,

"WITH

R is the required surface roughness coming out of the deformation zone of the strip, µm: R, is the surface roughness of the rolls, µm;

t is the temperature of zinc coatings

tee in front of the control dressio „level. WITH;

R is the surface roughness of the strip after the control of training, microns.

The task to the deformation zone of the strip with the calculated surface temperature will allow to obtain a galvanized strip with the required surface roughness.

The method is carried out as follows.

In a properly-trained mill they roll up previously prepared rolls. From the condition of preserving the flatness of the bands, the degree of demiration of the band is determined according to the dependence

T t, + ™ (R - R and

av:

)

At the same time, an increase in the coating temperature increases the coefficient

print micro-relief shaft-; on the strip surface. In order to stabilize the surface microrelief across the width of the strip, when training in rough rolls, the temperature of the coating increases in proportion to the number of rolled strips. In case of uneven development of the barrel rolls, the strip is set into the deformation zone e at unequal temperature of the coating along the width of the strip. In order to obtain strips with different roughness of the sides, heating (cooling) of the coating of one of the sides is performed.

Example. A zinc strip of 1 mm thick galvanized strip was trained on a regular training hot-dip galvanizing mill in rolls with a roughness of Rgt of 3.7 microns. It was required to obtain a strip with a surface roughness of RQ 2 μm. OF; conditions of preservation of flatness appointed compression of 0.9 in which carried out test training. In the course of the process of final grinding, the temperature of the zinc coating of the polishing zone entering the deformation zone was determined.

 40 °

(

.

sy, which was t,

With and

The roughness of the samples taken from the strip, which turned out to be equal to Rg 1.55 µm, was measured. According to

The formula calculated the temperature of the zinc coating required to obtain a strip with the required surface smoothness, which was equal to 122 ° C. Heating the coating to this temperature was made by excluding from the process of producing galvanized steel, locking the strip in a cold water bath. After heating the coating, strip striping was performed.

Editor V.Kovtun

Compiled by M.Reutov

Tehred V. Kadar: Proofreader G. Reshetnik

Order 701/12 Circulation 481 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

 - -- ---- "R-----..-.-.... - -, " ,"

Production and printing company, Uzhgorod, Projecto st., 4

2962456

(The prepaid strip production method due to the stabilization and control of the surface microrelief improves the quality of trained galvanized strips and allows an increase in the supply of sheets of strip with surface quality.

fO

15

20

25

Claims (1)

Invention Formula A method of producing galvanized strips, which includes rolling the billet, applying a zinc coating and training in shafts with a prepared surface, characterized in that, in order to obtain strips with a given surface roughness, after the coating is applied, control testing is performed, and the coating temperature of the incoming and the surface roughness of the deformation of the stripes coming from the source and regulate the temperature of the coating of the strip entering the source of deformation according to T t.  IS -) 5 0 0 where T is the heating temperature of the zinc coating required to obtain a strip with the required surface roughness, Cj required roughness is. surface emerging from the deformation zone of the strip, µm; surface roughness of the rolls, microns; temperature of zinc coating before control, training. WITH; surface roughness of the strip after the control of training, microns.  t. R ak