SU1447890A1 - Method of producing thin strip - Google Patents

Abstract

The invention relates to metallurgy, in tiacTHOcTH, to the production of thin strips from low carbon steels for shadow masks of color picture tubes. The purpose of the invention is to increase the plasticity and etching of raster holes while improving magnetic properties. Steel 08U was rolled on an endless cold rolling mill, then subjected to decarburization annealing and intermediate cold rolling. Continuous annealing is carried out according to the mode: heating at a rate of 48 ° C / s to, at this temperature for 50 seconds, followed by cooling at a rate of 2.9 ° C / s. The annealed strips were subjected to final cold rolling with a reduction rate of 32%. 2 tab. (L

Description

The invention relates to metallurgy, in particular, to the production of thin strips of low carbon steels for shadow masks for color kines.

The purpose of the invention is to improve the plasticity of the etching of raster holes while improving the magnetic properties.

Steel for shadow masks with a slit structure used in the manufacture of kinescopes and color television receivers must have a complex of mechanical and magnetic properties.

in tab. 1 shows the properties of steel for shadow masks with a slit structure.

In addition, the steel should have a good etching ability for raster-shaped slot holes.

The invention is carried out as follows.

Carried out cold rolling from low carbon steel to intermediate thickness, decarburizing annealing, intermediate cold rolling, recrystallization annealing by heating at a speed of 44 51 C / s (to a temperature of 640-680 C), exposure for 46-53 s and cooling from speed of 2.5-3.2 C / s.

The final cold rolling is done with the degree of deformation of 1.diya 2835%. .one ,

Example. Steel 0810 is smelted in an oxygen converter and cast on a continuous casting machine. Continuous casters are rolled in a hot rolling mill for a thickness of 3.2 mm, then the strip is etched and cold rolled in an endless cold rolling mill for a thickness of 0.5 MMj, then subjected to annealing on a continuous annealing (ANO) intermediate cold rolling mill thickness of 0.22 mm, heat treatment ANO by heating at a speed of 48 C / s to a temperature of 660 C, holding at this temperature for 50 s, then cooling at a speed of 2.9 C / s. The annealed strip is subjected to final cold rolling with a reduction rate of 32%. ,

The prepared metal in a welded condition is coated with a photosensitive layer, a raster field with slit-shaped holes is exposed to its surface, fixed and etched in a solution of ferric chloride. Thereafter, the strip is cut into individual masks, which are subjected to molding (spherization) by stretching with a degree of deformation of 7%.

In tab. 2 shows the embodiments of the method, as well as the properties of steel and the yield of masks after etching and molding.

As can be seen from the table. 2, when machining the steel strip according to the intended method (variants 2-4), maximum yields are obtained both after etching (87-99%) and after molding (83-97%). Mechanical and; The magnetic properties of steel strips fully meet the requirements,

In the case of large or small values of all (options 1 and 5) or at least one (options 6-15), the properties of steel and the yield of masks are much lower. The output of suitable masks with a slit structure is also low when processing steel by a known method.

It has been established that with a decrease in the degree of deformation during final cold rolling below 28%, an insufficient hardening of the strip occurs, which leads to a decrease in the yield of suitable etching masks in connection with the instability of the passage of the strip in the etching line of masks and an increase in the degree of deformation above 35% leads to loss the required level of plasticity, an increase in the anisotropy of properties, and also reduces the yield of yield during molding. Structure fa is characterized by the presence of grains with an unfavorable texture, lie which is eliminated during subsequent annealing.

The effect of the continuous annealing mode prior to the final cold rolling, on the properties of the finished strip and on the rejection during etching and molding of masks was also experimentally established. When heated with. at a rate of 44 C / s, an increase in the graininess of the particles occurs, which affects the plasticity index of the metal and reduces the yield of the material during etching and molding. Heating with

ABOUT

 a speed higher than 51 ° C leads to the formation of a fine-grained structure, reduces plasticity, which affects the yield during molding.

With a decrease in the exposure time at a temperature of 640 ° C less than 46 s, it does not have time to complete the recrystallization process, the structure is characterized by variability and fine grain size, which reduces the yield of the material during subsequent etching and molding of the masks due to breaks in the bridges. If the holding time at a temperature of 680 ° C is exceeded for more than 53 seconds, the process of collective recrystallization begins, which leads to a sharp heterogeneity of properties and structure, and this in turn causes the appearance of defects during mask forming and reduces the yield of the suitable one.

A decrease in the cooling rate below 2.5 ° C / s has a significant effect on grain growth after aging, as well as the formation of an unfavorable texture.

When the cooling rate is below 2.5 ° C / s, the required level of plasticity is not reached and the technical and economic advantages of the proposed method are reduced,

ten

20

25

that the final rolling with a reduction of 28-35% after heat treatment in the continuous mode unit according to the mode: heating at a speed of 44-51 С / s to 640-680 ° С, holding 46-53 s and cooling. 2.5-3.2 ° C / s

ensure the formation of the optimal structure and texture of steel, which allows to obtain the required complex of mechanical and magnetic properties, to ensure the yield of masks with a gaseous structure of at least 83%.

Claims (1)

Invention Formula Method for the production of thin strips, mainly for shadow masks from mild steel, including cold strip rolling, decarburization annealing, intermediate cold rolling, recrystallization annealing and final cold rolling, characterized in that, in order to improve ductility while improving magnetic properties, recrystallization waste suitable for molding. In case of an early-30 burn, they lead by heating at a rate of these cooling above 3.2 S / s did not have time-44-51 ° C / s to a temperature of 640-680 s, The required diffusion gaps at this temperature go into heat processes, as a result of which an increase of 46–53 s and cooling time increases the rate of magnetic aging of 2.5–3.2 s / s, and the final coercive force decreases. - 35 to one rolling lead with the degree of delicacy of steel. Formation 28-35 °. 1447890 The technical and economic advantages of the proposed method are that the final rolling with a reduction of 28-35% after heat treatment in the continuous mode unit according to the mode: heating at a speed of 44-51 С / s to 640-680 ° С, holding 46-53 s and cooling. 2.5-3.2 ° C / s ensure the formation of the optimal structure and texture of steel, which allows to obtain the required complex of mechanical and magnetic properties, to ensure the yield of suitable masks with a gap structure of at least 83%. Invention Formula Method for the production of thin strips, mainly for shadow masks from mild steel, including cold strip rolling, decarburization annealing, intermediate cold rolling, recrystallization annealing and final cold rolling, characterized in that, in order to improve ductility while improving magnetic properties, recrystallization from 40-58 22-36 Not less than 33 No more no more than 1.08%