WO2007003109A1

WO2007003109A1 - Once-cold-rolled steel strip for shadow mask and its manufacture process

Info

Publication number: WO2007003109A1
Application number: PCT/CN2006/001458
Authority: WO
Inventors: Jun Li; Shuangjie Chu; Hailing Guan; Xiuzhen Lin; Renzhong Jin; Jianqing Gong
Original assignee: Baoshan Iron & Steel Co., Ltd.
Priority date: 2005-06-30
Filing date: 2006-06-26
Publication date: 2007-01-11
Also published as: JP2008545060A; KR101049303B1; RU2008103365A; DE112006001709T5; KR20080038145A; CN1888118A; CN100430511C; RU2381294C2; JP5035806B2; DE112006001709B4

Abstract

Once-cold-rolled steel strip for shadow mask and its manufacture process. The process includes: smelting, casing, hot-rolling with a rolling finish temperature of 880~900 , coiling at 510~610 ; pickling and cold-rolling; trimming to remove defects on edge such as cracks and burrs; continuous annealing, in which the steel temperature in heating stage and soaking stage is 675~695 and soaking time is 20~35s; dry-flattening using levelling machine with double frames and 6 rollers. The once-cold-rolled steel strip for shadow mask manufactured from the composition, process and process parameters of the present invention is excellent in properties, with significantly reduced or even disappearing longitudinal streaking on surface. The steel strip is good in shape, high in production efficiency, low in manufacture cost, and the quality of which could better meet the requirements of steel strip for shadow mask of CRT.

Description

Cold rolled shadow mask strip and manufacturing method thereof

The invention relates to a shadow mask strip for a color picture tube and a manufacturing method thereof, in particular to a material control technology for the material properties of the cold-rolled shadow mask strip and a control technique for the surface longitudinal stripe and shape. Background technique

Chinese patent ZL01113107.1 provides a method for producing shadow mask strip by one-time cold rolling and continuous annealing, which overcomes the shortcomings of the international patent (application number W096/13618):

From the chemical composition point of view, the high carbon content makes the final shadow mask strip performance worse. The addition of a small amount of Nb is not enough to fix the carbon of the steel, and the anti-aging property is obviously improved, while the Nb content is increased. It can improve the anti-aging performance, but at the same time it is unfavorable to the magnetic properties, and the production cost increases;

From the point of view of the production process, the continuous casting slab is easily cracked during the steelmaking and continuous casting process, and is very sensitive to the hot rolling process parameters, especially the recrystallization temperature of the final shadow mask stencil. The user must greatly increase the annealing temperature and increase the energy consumption, and the increase of the temperature will cause the shadow mask stencil to be easily bent after annealing, the shape of the plate is deteriorated, and the bonding defects at the time of high temperature annealing are correspondingly increased.

The Chinese patent ZL01113107.1 provides a simple production process and a significant increase in productivity. The patented technology uses ultra-low carbon steel (pure iron) or a small amount of strong carbide forming element Ti or Ti and Nb, ie IF steel, in ultra-low carbon steel, so that the carbon mainly exists in the form of carbide, large The range reduces the solid solution carbon content in the steel, improves its anti-aging performance, and ensures the stamping formability, especially the forming uniformity; the shadow mask strip is made by rational design of the chemical composition and adjustment and optimization of the production process parameters. The material properties and magnetic properties meet the requirements of use. The advantage of the shadow mask strip produced by the patent is that the material properties and subsequent processing performance are good, the production process is simple, and the production cost is lower than that of the conventional secondary cold-rolled shadow mask strip, but the patent also has obvious disadvantages: The patent's chemical composition range is still not ideal. Practice has proved that certain elements must be strictly controlled, such as C, Mn, Ti, Al, Nb, otherwise the material and process properties will fluctuate greatly, affecting users' use, and some Some elements such as 0 and S are too strict, resulting in obvious production costs Secondly, there is no key technical parameters in the production process of the patent that significantly affect the properties of the shadow mask strip, such as hot-rolled slab heating temperature, finish rolling temperature, continuous annealing temperature and time, etc., or Unreasonable control of process parameters, such as coiling temperature and flat elongation, especially without parameters that significantly affect the surface quality and shape of the plate, such as flat work roll crown, surface roughness, flattening tension, rolling The force and bending force are optimized and strictly controlled, and the surface of the shadow mask strip produced according to the conventional flattening process parameters is prone to longitudinal streaks, and the side waves are severe and the surface roughness is not satisfactory. The earth affects the appearance and affects the normal use of the customer. Summary of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shadow strip steel which is once cold rolled and a method of manufacturing the same, which enables the surface appearance and performance of the shadow mask strip to be produced to meet the requirements of the user. To this end, it is necessary to significantly improve the material properties and subsequent processing properties of a cold-rolled shadow mask strip, improve production efficiency and board stability, reduce production costs, and easily produce longitudinal stripes and side waves for the surface of a cold-rolled shadow mask strip. The problem is to provide a control technique.

In order to achieve the above object, the present invention employs the following technical solution: a cold-rolled shadow mask strip having a composition weight percentage of:

C 0.002, preferably C 0.0017

Ti 0.035-0.05

Mn 0.10-0.25, preferably 0.15~0.25

A1 0.03-0.06

Cr 0.002-0.03

Si 0.03

N 0.003

P 0.012

S ^ 0.01

O 0.004

The balance of Fe and inevitable impurities.

The method for manufacturing a cold-rolled shadow mask strip of the present invention comprises the following steps,

a. Smelting, casting, hot rolling, hot rolling finishing temperature 880~900 °C, coiling temperature 510~ 610 ° C;

b. pickling cold rolling;

c Prepare the trimming of the unit to remove edge defects such as edge cracks and burrs;

d. continuous annealing, continuous annealing of the heating section, the soaking section plate temperature is controlled between 675~695 °C, soaking time is 20~35s;

e. Flat, using a two-stand six-roll leveling machine to dry and flat, the work roll diameter is 410~

460mm, work roll crown is 0.12~0.24mm; - frame rolling force is 9,000~ 12,000KN, and two-stand rolling force is 6,000~8,000KN.

Further, the surface hardness of the work roll is Hs 93 to 97, and the surface hardness of the intermediate roll is Hs 81 to 85; the surface of the work roll is preferably subjected to chrome plating after being textured, and the texturing treatment includes electrosparking treatment, laser hair For the treatment, or the blasting treatment, etc., the electrosparking treatment is preferred.

The average surface roughness (Ra) of the work roll surface after texturing or further chrome plating ranges from 0·80 to 1.20 μ ιη, and the unit length (cm) peak number (PC) is 130 to 170.

The double-stand bending force is 300~500KN.

The unit tension of the double-stand tempering machine is controlled at ll~13kg/mm ² , and the intermediate and outlet unit tension is controlled at 35~48kg/mm ² .

The flattening elongation is 1.3 to 2.0%. detailed description

The production process parameters of the above production method are in addition to the heating temperature of the hot-rolled slab described in ZL011 13107.1 being 1,200-1,250 ° C, and the cold rolling deformation is 87-93%, and the hot rolling process parameters are optimized to: hot rolling The finish rolling temperature is 880-900 ° C, and the hot rolling coiling temperature is 510-610 ° C. In addition, the preparation of the trimming process of the unit is added before the continuous annealing to facilitate the safety of the board. The subsequent continuous annealing and flat process parameters are also strictly controlled. The main process parameters are as follows: Annealing temperature and time are 675-695 °. And 20-35s _; flat work roll crown and roll diameter are 0.12-0.24mm and 410-460mm respectively; flat roll surface roughness Ra and PC values are: 0.80-1.20 rn and 130-170/cm;

The invention has the following changes from the chemical composition point of view compared with the patent ZL01113107.1: First, the range of ( Ti, Mn and A1 is reduced, so that the main elements are strictly controlled, and the performance of the shadow mask strip is more stable; Second, without adding expensive Nb elements, the production is greatly reduced. Cost; Third, the range of O and S is relaxed, which reduces the cost of the steelmaking process.

Compared with the comparative patent ZL01 1 13107.1, the invention has the following changes: First, the hot rolling finishing temperature and the coiling temperature are lowered, and the range is reduced, which is beneficial to controlling the quality of the hot rolled slab and improving the pickling speed. And the surface quality of the finished product and greatly reduce the production cost; second, the continuous annealing temperature is reduced, the temperature range is reduced, and the soaking time is shortened, which means that the production speed is increased, and therefore, the continuous annealing temperature and the soaking time are reduced. It not only reduces the production cost, but also improves the production efficiency and product quality. Thirdly, it increases the preparation process of the unit trimming edge, which can effectively remove the strip edge defects (such as edge cracks, burrs, etc.) and improve the safety of the board. And board efficiency, especially the safety of the wide and thin material. Fourth, and most importantly, the present invention provides a complete set of flat technical parameters, including flattening method, smoothing work roll diameter, work roll crown, smoothing roll surface finish and post-treatment method, surface hardness, surface roughness Detailed parameters such as flattening elongation, rolling force, tension and bending force make the surface quality and shape quality of the strip significantly improved.

The shadow mask strip produced by using the chemical composition and the production process parameters provided by the patent of the invention has excellent material properties and surface quality, the longitudinal stripe of the surface is obviously reduced or even eliminated, and the shape of the sheet is excellent, and the chemical composition and production process of the patent are utilized. The parameters can also be used for the production of double-length shadow mask strips, such as shadow mask strips with a width of 490 mm. If the production process of the comparative patent ZL01 1 13107.1 is used, only single-size production can be carried out, the production efficiency is low, and the finished product ratio is higher. Low, and the process of this patent can be used to double-size (S卩490mm X 2) production, the production efficiency is doubled, and the finished product rate is increased from 70% to over 90%.

The control and principle of the present invention are as follows:

较低Use lower hot rolling finish rolling temperature and coiling temperature to reduce the surface scale of the strip steel, so that the surface quality is strictly controlled from the upstream process, so that the possible defects generated by the strip during the hot rolling stage are minimized. The narrowing of the range also makes the control more precise, which is conducive to the stable control of the strip quality.

The invention increases the preparation process of the trimming unit, because the shadow strip steel strips in the flattening process, under large tension conditions, the defects of the strip edge (such as burrs and small cracks) are easy to cause the flat strip. The shadow mask strip intermediate product of the invention is cut by the CPL (steel coil preparation unit) before being subjected to CAPL (continuous annealing and flattening), completely removing the edge cracks and burrs generated in the previous process, and avoiding the large tension during the flattening. In the case of the broken strip, the shadow mask strip is more effective in improving the surface quality of the strip and eliminating streaks under conditions of large tension and rolling force. After preparing the trimming of the unit, the shadow mask strip is subjected to continuous annealing. The essence is to re-anneal the strip hardened after cold rolling to improve the strip shape and structure and partially eliminate the work hardening. High-temperature recovery annealing is performed near the recrystallization temperature of the material, so the material properties of the strip are very sensitive to the annealing temperature, so the plate temperature and soaking time of the heating section and the soaking section are key parameters of the continuous annealing process, and practice has proved that The higher the temperature, the more favorable it is to control the longitudinal stripe, but the too high temperature will cause the strip to recrystallize and nucleate locally, local recrystallization occurs, and even the grain grows, which is not conducive to the performance of the finished material of the shadow mask strip. Control, it is also unfavorable to control the texture of the masked reticle after the second annealing. After the experiment, for the shadow mask strip of the present invention, the heating section and the soaking section of the continuous annealing process are controlled at Between 675 and 695, the soaking time is controlled at 20-35 s. The annealing temperature and time are matched. The lower the annealing temperature and the shorter the time, the material can not achieve the purpose of improving the shape and material by high temperature recovery. On the contrary, the annealing temperature is higher and the time is too long, although the shape of the plate can be more Good improvement, but the strip is prone to local recrystallization, resulting in uneven material and deteriorated etching performance of the shadow mask strip.

After continuous annealing, the shadow mask strip enters a very important leveling process. The main functions of leveling are as follows:

1. Improve the strength and hardness of the shadow mask strip after high temperature recovery annealing;

2. Improve the shape of the plate and obtain a good straightness of the strip;

3. Give the strip surface a suitable surface topography, including Ra, Rmax, Sm and Rsk;

4. Eliminate various surface defects of the shadow mask strip.

Based on the above functions of the leveling machine, the relevant parameters of the leveling machine must be strictly controlled, including the leveling method, the flattening elongation, the flat work roll crown, the work roll diameter, the surface roughness, the surface treatment state, the surface hardness and the double frame. The flat rolling force, the tension of each section, the bending force, and especially the matching of the last three technical parameters determine the shape, surface topography, material properties and surface defects of the shadow mask strip. After many industrial trials and groping, the following technical parameters of the flattening process have been obtained - before the strip is flattened, various defects may occur in each process, especially roll marks, indentations, scratches, etc., but after two-stand flattening After a certain deformation of the machine, it can eliminate or reduce the surface defects of the strip. In order to ensure the improvement of the surface quality of the strip and the control of the surface topography, the elongation is controlled at 1.3-2.0%, and the flat elongation of the conventional hard material. Far less than 1.3%. It has been found through experiments that in order to increase the flattening elongation, the rolling force, unit tension and bending force must be greatly increased. However, the excessive flat elongation tends to cause unstable production, the shape of the steel plate is poor, and the service life of the smoothing roll will also be shortened. If the elongation is too small, the surface roughness of the work roll is difficult to be copied to the surface of the strip, so that the roughness of the strip is difficult to meet the requirements, and the surface defects caused by the pre-process are difficult to reduce and eliminate;

The work roll width of the double-stand tempering machine for the shadow mask strip is 0.12-0.24 mm. This convexity is much larger than that of the flat work roll of the rolled general steel grade. It has been found through experiments that, for the shadow mask strip of the present invention, if the convexity is too high, more than 0.24 mm, it is easy to generate a medium wave, and The convexity is too low, and below 0.12mm, it is easy to generate side waves, which are not conducive to the shape control;

The double-stand tempering machine has a roll diameter of 410-460mm. If the roll diameter is too large, the actual rolling force will increase, and the power of the flat motor drive motor will also increase. Otherwise, the elongation will be less than 1.3%, the roll diameter will be too small, the actual rolling force will be too small, and the surface morphology of the strip will be The surface quality is difficult to control, and the roughness of the work rolls cannot be copied to the strip surface as required, and the surface defects are difficult to eliminate.

After repeated trials and user tests, it was determined that the average surface roughness (Ra) of the work rolls of the double-stand tempering machine was 0.80-1.20 μ ιη, and the unit length (cm> peak number (PC) was 130-170. The work roll Ra and PC values directly affect the Ra, Rmax, Rsk and Sm values of the shadow mask strip. Therefore, the work roll Ra and PC values must be moderate, and the surface roughness is too large, which will affect the boundary of the shadow mask mesh hole. Too small affects the degree of vacuum of the shadow mask strip when it is evacuated before exposure.

The surface of the work roll of the double-stand tempering machine is preferably chrome-plated after being subjected to sparking. The life of the work rolls after chrome treatment is significantly prolonged, and it is also beneficial to improve and stabilize the various indicators for controlling the surface roughness of the strip;

The surface hardness of the work rolls of the two-stand tempering machine is Hs 93-97, and the surface hardness of the intermediate rolls is Hs 81-85. If the roll surface hardness is too high or the surface hardness range is small, for example, the work roll Hs 95-97, the service life of the roll will be shortened, and the chrome plating amount is required to increase, the production cost is increased, the roll surface hardness is too low, and the strip surface is prone to roll. Print

The unit tension of the double-stand tempering machine is controlled at l l-13kg/mm ² , and the intermediate and outlet unit tension is controlled at 35-48kg/mm ² . Excessive tension, easy to break, unstable production, too small tension, poor steel plate shape and surface quality;

The first frame has a rolling force of 9,000-12,000 KN and the second frame has a rolling force of 6,000-8,000 KN. If the rolling force is too large, the strip is prone to edge waves, the energy consumption increases, the rolling force is too small, the roll surface roughness is difficult to replicate to the strip surface, and in order to achieve the required flat elongation The tension has to be increased, which increases the risk of breakage.

The double-stand bending force is 300-500KN. The bending force is too small, which is easy to produce side waves. Especially when rolling a wide shadow mask strip, it is more prone to side waves, so the maximum capacity of the equipment is controlled by the bending force of one frame and two frames. 500KN, the bending force is too large, the equipment capacity is not up to.

Through the control of the above-mentioned series of flattening related technical parameters, the obtained shadow mask strip not only retains all the advantages of the patent ZL011 13107.1, but also improves the production efficiency, reduces the production cost, and effectively eliminates the surface defects. The shape of the plate is good, especially the longitudinal stripes on the surface are almost completely gone. Example

The contents of the present invention will be further described by way of examples in accordance with the various process parameters of the invention.

The process of each implementation case is as follows: The continuous casting slab is heated to the hot rolling blanking temperature before hot rolling, and is coiled after rough rolling, finish rolling and laminar cooling, after 2-3 days of room temperature cooling, and then CDCM unit (washing and cold rolling), and then through the preparation of the unit trimming, and CAPL unit (continuous annealing and finishing), and finally through the internal defects and surface quality inspection, trimming and winding and other finishing processes to produce shade Finished steel strip.

The chemical composition is shown in Table 1. The main technical parameters are shown in Table 2. The quality performance is shown in Table 3.

Table 3 Quality performance of the example and comparison

Surface roughness Index Finished material properties Surface longitudinal stripes Plate shape wave height (mm) Edge crack

Ra ( μ m ) Requirements Meet the requirements of use No obvious surface longitudinal streaks Waves 2.0 0.40-0.70 None Example 1 Excellent Basic elimination Side waves 1.3 0.43 None

2 Excellent Complete elimination Side wave 1.0 0.50 None

3 Excellent Complete elimination Medium wave 1.0 0.58 None

4 excellent basic elimination side wave 1.0 0.42 no

5 Excellent Complete elimination Side wave 1.0 0.45 No

6 Excellent Complete elimination Side wave 1.5 0.55 None

7 good basic elimination side wave 2.0 0.47 no

8 Good Complete elimination Medium wave 2.0 0.60 None Comparative 1 Excellent *Significant surface longitudinal stripes * 2.5 0.50 *Yes

2 Excellent * Has obvious surface vertical stripes * 3.0 0.40 * Have

3 Excellent * There are obvious surface vertical stripes * 3.0 0.59 * Yes Note: * is unqualified. By adopting the production process and parameters described in the invention, the longitudinal stripe on the surface of the shadow mask strip is obviously reduced or even eliminated, the surface roughness can meet the requirements, the quality is very stable, and the production efficiency is greatly improved. However, the production process of the comparative patent ZL01113107.1 is not strictly controlled due to some of its process parameters. The shadow mask produced by the mask has poor shape, and there are defects such as vertical stripe and edge crack on the surface, and the surface roughness value is also unstable.

Claims

Rights request

1. A cold-rolled shadow mask strip with a composition weight percentage of:

C ^0.002%

Ti 0.035-0.05%

Mn 0.10-0.25%

Al 0.03-0.06%

Cr 0.002-0.03%

Si ^0.03%

N 0.003%

P 0.012%

S ^0.01%

O 0.004%

The balance of Fe and inevitable impurities.

The primary cold-rolled shadow mask strip according to claim 1, wherein C 0.0017%,

Mn 0.15 to 0.25% by weight.

3. A method for manufacturing a cold-rolled shadow mask strip, comprising the following steps,

a. smelting, casting, hot rolling, hot rolling finishing temperature 880~900 ° C, coiling temperature: 510~ 610 ° C;

b. pickling cold rolling;

c. Prepare the trimming of the unit and remove edge defects such as edge cracks and burrs;

d. continuous annealing, the heating section of the continuous annealing, the plate temperature of the soaking section is controlled between 675 and 695 ° C, and the soaking time is 20 to 35 s;

e. Leveling, flattening with two-stand six-roll leveling machine, work roll diameter is 410~460mm, work roll crown is 0.12~0.24mm; - frame rolling force is 9,000~ 12,000KN, two machine The rolling force of the frame is 6,000 to 8,000 KN.

The method for producing a cold-rolled shadow mask strip according to claim 3, wherein the surface hardness of the work rolls is Hs93 to 97, and the surface hardness of the intermediate rolls is Hs81 to 85.

A method of manufacturing a shadow mask strip according to claim 3, wherein the surface of the work roll is subjected to texturing treatment or further chrome plating. π

The method for manufacturing a cold-rolled shadow mask strip according to claim 3 or 5, wherein the surface roughness of the surface of the work roll after roughening or further chrome plating is 0.80 to 1.20. μ ιη, unit length (cm) The number of peaks (PC) is 130 to 170.

The method of manufacturing a cold-rolled shadow mask strip according to claim 3, wherein the double-stand bending roller force is 300 to 500 KN.

The method for manufacturing a cold-rolled shadow mask strip according to claim 3, wherein the unit tension of the double-stand tempering machine is controlled at ll~13kg/mm2, and the intermediate and outlet unit tension is controlled at 35~ 48kg/mm2.

The method of producing a cold-rolled shadow mask strip according to claim 3, wherein the flat elongation is from 1.3 to 2.0%.

10. A method according to claim 5 or claim 6 wherein said texturing treatment is an electrosonic treatment.