KR101082137B1 - Apparatus for manufacturing cold rolled stainless coil - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing a hot rolled stainless coil, which is provided by winding a hot rolled strip that has been pickled without annealing, into a cold rolled stainless coil. A first rolling facility wound with a first cold rolled coil, a second rolling facility winding a second cold rolled strip provided by unwinding the first cold rolled coil and wound with a second cold rolled coil, and the second cold rolling An annealing pickling system for annealing and winding the second cold rolled strip provided by unwinding the coil; In the first rolling facility, the hot rolled strip is cold rolled at a reduction ratio of 50 to 60%, and in the second rolling facility, the first cold rolled strip is cold rolled at a reduction ratio of 40 to 50%, and the second cold rolling The strip is characterized in that passing through the annealing pickling facility at a plate speed of 90 ~ 110mpm, it is possible to produce a cold rolled strip having a good surface quality through the cost reduction effect due to the process shortening and the effect of maximizing the production efficiency of the rolling mill.

Continuous process, unit process, tandem rolling mill, Z-Mill rolling mill

Description

Cold rolled stainless steel coil manufacturing equipment {APPARATUS FOR MANUFACTURING COLD ROLLED STAINLESS COIL}             

BRIEF DESCRIPTION OF THE DRAWINGS The figure which showed schematically the structure of the prior art example which manufactures a cold rolled stainless coil.

2 is a view schematically showing a configuration of another conventional example of manufacturing a cold rolled stainless coil;

Figure 3 is a block diagram schematically showing the configuration of a cold rolled stainless steel coil manufacturing apparatus according to the present invention;

4 is a graph showing the relationship between elongation, tensile strength and yield strength according to annealing temperature;

5 is a graph showing the relationship between the plate speed with respect to the annealing temperature and elongation.

Description of the Related Art

110, 120: rolling equipment

112, 122: rolling mill

114, 124, 136: uncoiler

116, 126, 138: coiler                 

130: annealing pickling equipment

132 annealing furnace

134: pickling area

140: cold rolled stainless steel coil

The present invention relates to an apparatus for manufacturing a hot rolled strip into a cold rolled stainless coil through a cold rolling process and an annealing pickling process. The present invention relates to a cold rolled stainless steel coil manufacturing apparatus having a cold rolled coil and then wound with a cold rolled coil to reduce production cost and have a good surface quality.

In general, stainless steel sheets (hot bands, ie black bands) manufactured by hot rolling the strip or by strip casting have been subjected to annealing, shot blasting and pickling. It is converted into a white band through a pickling process. The white steel sheet is manufactured into a cold rolled steel sheet, that is, a final dimension product, through a cold rolling process. These final dimension products are annealed to remove internal stresses, soften steels or adjust the crystal structure. If necessary, the annealed final dimension product is corrected in the correction line, plated and processed into high value products.

As described above, in order to manufacture a hot rolled steel sheet into a cold rolled steel sheet, a number of unit processes such as a hot rolled steel sheet annealing process, a hot rolled steel sheet pickling process, a cold rolling process, and a cold rolled steel sheet annealing process are required and corrected as necessary. Additional unit processes such as process and / or plating process are required. In each of the unit processes, a pay off reel for unwinding the coil is provided at the entry side, and a tension reel for winding the strip is provided at the exit side. In manufacturing, relatively high installation costs are required.

Since one unit process is not affected by another unit process, the operation efficiency of each unit process can be maximized. However, there is a relatively large production time as well as a relatively excessive installation cost, which requires additional facilities for winding up and unwinding the product produced in each unit process and for transferring the product between the unit processes. As a result, there was a limit to the yield of cold rolled steel sheet by unit processes.

Recently, many efforts have been made to reduce the manufacturing cost of stainless steel products. For example, methods for producing low cost cold rolled stainless products by process shortening, such as single-continuous operation directly connecting a plurality of unit processes have been proposed.

For example, U.S. Patent No. 5,197,179, as shown in Figure 1, cold rolling the hot rolled stainless strip, annealing, and pickling step consisting of one continuous line to form the hot rolled stainless strip A method of converting into conditions suitable for subsequent cold rolling to be dimensioned is disclosed. However, this conventional technique requires additional unit processes such as a subsequent cold rolling process and a cold rolled sheet annealing process in order to manufacture a cold rolled stainless steel sheet of final dimension, so that the production yield of cold rolled steel sheet of final dimension according to time and cost is required. There was a limit.

In addition, US Patent No. 5,606,787, as shown in Figure 2, the rolling mill for rolling the hot rolled steel strip to the thickness of the final dimension, continuous process line for producing the final dimension product by continuously installing the annealing zone, pickling zone Is disclosed. However, in general, when cold rolling is performed at a rolling reduction rate of about 70% or more during cold rolling, a hit scratch occurs on the surface of the cold rolled strip. It becomes difficult to obtain a cold rolled product of thickness. In addition, in the conventional continuous process line, when the width of the hot rolled steel sheet strip is 1m or more, shape correction is impossible.

Therefore, there is a need for an apparatus that can produce a cold rolled strip having a relatively low production cost and a high yield in a short time and having a good surface quality of the final target dimension.

The present invention has been proposed to solve the conventional problems as described above, the production of cold rolled stainless coil that can produce a good quality cold rolled product while reducing the production cost as well as the production increase effect through the process shortening. The object is to provide a device.

In order to achieve the above object, according to the present invention, an apparatus for manufacturing a hot rolled stainless coil, which is provided by winding a hot rolled strip that has been pickled without annealing, is formed of a cold rolled stainless coil. A first rolling facility for cold rolling cold and wound with a first cold rolling coil, a second rolling facility for cold rolling a second cold rolling strip provided by unwinding the first cold rolling coil and winding with a second cold rolling coil; An annealing pickling apparatus for annealing and winding a second cold rolling strip provided by unwinding the second cold rolling coil; In the first rolling facility, the hot rolled strip is cold rolled at a reduction ratio of 50 to 60%, and in the second rolling facility, the first cold rolled strip is cold rolled at a reduction ratio of 40 to 50%, and the second cold rolling The strip is characterized in that passing through the annealing pickling facility at a mailing speed of 90 ~ 110mpm.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

First, referring to FIG. 3, the apparatus for manufacturing a cold rolled stainless coil according to the present invention has a first rolling mill 112 that primarily cold-rolls a pickled hot rolled strip or a strip cast and pickled hot rolled strip without annealing. And a second rolling facility (120) having a first rolling facility (110) and a second rolling mill (122) for secondarily cold rolling a cold rolled strip that is cold rolled by the first rolling mill (112).                     

At this time, the first rolling equipment 110 is installed on the inlet side of the first rolling mill 112 and the first uncoiler 114 to wind up the hot rolled stainless coil 102 provided by winding the hot rolled strip, and the first The first coiler 116 is installed at the exit side of the rolling mill 112 and winds up the first cold rolled strip rolled by the first rolling mill 112 with the first cold rolling coil.

The second rolling equipment 120 is installed at the inlet side of the second rolling machine 122 to unwind the first cold rolling coil provided from the first coiler 116 of the first rolling equipment 110 ( 124 and a second coiler 126 provided on the outlet side of the second rolling mill 122 to wind the second cold rolling strip rolled by the second rolling mill 122 with the second cold rolling coil.

The first rolling mill 112 is in contact with the surface of the progressing hot rolled strip and has a work roll 112a having a diameter of about 410 to 430 mm, and bending of the work roll during rolling of the hot rolled strip by the work roll 112a. In order to prevent this, it has a backup roll 112b. That is, the first rolling mill 112 is preferably composed of a tandem mill (Z-Hi mill).

At this time, it is preferable that the first rolling equipment 110 has a plurality of first rolling mills 112, preferably four stand first rolling mills 112. This is to effectively reduce the thickness of the hot rolled strip that is cold rolled in the first rolling facility 110 through only one pass, as described below. For example, in the first rolling facility 110, the thickness of the hot rolled strip is reduced to a reduction ratio of about 50 to 60%. This is because when the reduction ratio is less than 50%, the surface reduction effect on the hot rolled strip is insignificant, and when the reduction ratio exceeds 60%, surface defects such as heat scratches may occur.

On the other hand, the second mill 122 is provided to provide a beauty to the surface of the first cold rolling strip discharged from the first mill 112 and to reduce the final thickness to the target dimension. Thus, the second rolling mill 122 has a work roll 112a in contact with the surface of the first cold rolling strip and having a diameter of about 90 to 110 mm, and the work roll 122a is supported by a plurality of backup rolls. That is, the second rolling mill 122 is preferably composed of a Z-milling mill (Z-Rolling Mill; Sendzimir Mill) consisting of only one stand. In this case, in the second rolling facility 120, the first cold rolling strip is reduced in thickness while reversibly passing through the second rolling mill 122. Preferably, the first cold rolled strip has a good surface with a thickness reduction rate of about 40 to 60% and no heat scratching while passing the second rolling mill reciprocating about 7 to 9 times.

In addition, the apparatus for manufacturing cold rolled stainless steel coil according to the present invention includes an annealing pickling facility including an annealing furnace 132 and an pickling zone 134 for continuously annealing the second cold rolled strip that is cold rolled from the second rolling mill 122. 130). The annealing pickling facility 130 is installed at the inlet side of the annealing furnace 132 to release the third uncoiler 136 which winds up the second cold rolling coil supplied from the second coil 126 of the second rolling facility 120. And a third coiler 138 which is provided on the exit side of the pickling zone 134 and winds the pickled second cold rolled strip with the cold rolled stainless coil 140.

On the other hand, the second cold rolled strip manufactured by passing through the first mill 112 and the second mill 122 has a high strength because its crystal structure is dense. Therefore, the cold rolled strip produced by the present invention preferably has an elongation that satisfies the demand. For this purpose, the annealing temperature in the annealing furnace 132 is preferably maintained at 810 ~ 950 ℃. That is, referring to FIG. 4 showing the relationship between the annealing temperature, the elongation rate, and the tensile strength and the yield strength, as the annealing temperature increases, the elongation rate increases, while the yield strength (YS) and the tensile strength (TS) decrease. have. Therefore, in order to provide a cold rolled strip having an appropriate yield strength and tensile strength and elongation, the annealing temperature is maintained at 810 ~ 950 ℃, preferably annealing temperature is maintained at 850 ~ 950 ℃.

Referring to FIG. 5 showing the relationship between the sheet speed (mpm) and the elongation according to the annealing temperature, the elongation increases as the annealing temperature increases when the sheet speed (mpm) of the cold rolled strip passing through the annealing furnace 132 is 100 mpm. It can be seen. However, it can be seen that when the sheet speed is 150mpm, the elongation decreases when the annealing temperature exceeds 880 ° C. Therefore, it is preferable to keep the plate speed of the cold rolled strip passing through the annealing furnace 136 at about 90 to 110 mpm.

On the other hand, in the annealing pickling equipment 130, between the pickling zone 134 and the third coiler 138, a clean drying line for removing and drying the acid solution from the surface of the second cold rolled strip that has been pickled Calibration lines for correcting deformation and / or defect detection devices for detecting surface defects of strips may be provided.

Hereinafter will be described the operation of the cold rolled stainless steel coil manufacturing apparatus according to the present invention.

First, the pickled hot rolled strip or strip cast and pickled hot rolled strip without annealing is provided to the hot rolled stainless coil 102 by a winder (not shown). At this time, the hot rolled stainless coil 102 is provided to the first rolling facility (110). The hot rolled strip provided by the hot rolled stainless coil 102 is unwound from the first uncoiler 114 installed at the inlet side of the first rolling facility 110 to proceed to the first mill 112. The hot rolled strip is cold rolled at a reduction ratio of about 50 to 60% while passing through the first mill 112. The first cold rolling strip passing through the first rolling mill 112 is wound into the first cold rolling coil in the first coiler 116 installed at the outlet side of the first rolling mill 112.

In addition, the first cold rolling coil is transferred to the second rolling facility 120 by a moving means (not shown). At this time, the first cold rolling strip provided by being unwound from the second uncoiler 124 installed at the inlet side of the second rolling facility 120 is about 7 to 9 times of the second rolling mill 122. Cold rolling is carried out at a reduction ratio of about 40-50% while reciprocating. The second cold rolled strip produced in the second mill 122 is wound into the second cold rolled coil in the second coiler 126 installed at the outlet side of the second mill 122.

Thereafter, the second cold rolled coil is transferred to the annealing pickling facility 130 by a conveying means (not shown). In this case, the second cold rolling strip provided by being unwound from the third uncoiler 136 installed at the entrance side of the annealing pickling facility 130 is annealed while passing through the annealing furnace 132. At this time, the interior of the annealing furnace 132 is maintained at a temperature of about 810 ℃ ~ 950 ℃, the second cold rolled strip is subjected to annealing while passing through a plate speed of about 90 ~ 110mpm.

The second cold rolling strip passing through the annealing furnace 132 is pickled while passing through a molten salt bath in the pickling zone 134. Then, it is wound with a cold rolled stainless coil 140 in a third coiler 138 installed at the rear end of the annealing washing facility 130 passing through the pickling zone 134.

On the other hand, the second cold rolling strip passing through the pickling zone 134 is cleaned in a clean line (not shown) before being wound in the third coiler 138 to remove the salt solution remaining on the surface thereof and then dried. Can be. In addition, the second cold rolled strip passing through the pickling zone 134 may be calibrated while passing through a flattening device (not shown) before being wound up.

As described above, the pickled hot rolled strip is reduced to the final target thickness while passing through a first mill having a relatively large diameter work roll and a second mill having a relatively small diameter work roll and having a beautiful surface. It can be made into cold rolled strips.

[Example]

430 steel, 439 steel having a basic composition of C: 0.03% or less, Si: 1.0% or less, Mn: 1.0% or less, P: 0.04% or less, S: 0.03% or less and Cr: 10.5 to 19% Low chromium ferritic stainless molten steel, which constitutes 409L steel and 436L steel, is made into a strip by a casting process. These strips are made into hot rolled strips through a hot rolling process. The hot rolled strip is wound with a hot rolled stainless coil after passing through the pickling zone without annealing. At this time, the hot rolled strip in the pickling zone is conditioned and pickled while passing through a molten salt bath of kolene type to remove the scale present on the surface.                     

The hot rolled stainless coil is cold rolled at a rolling reduction rate of about 50 to 60% while passing through a tandem rolling mill to reduce its thickness. The cold rolled strip, which is cold rolled through the tandem rolling mill, is cold rolled at a rolling reduction rate of about 40 to 50% while passing through the Z-Mill rolling mill 7 to 9 round trips, and is cold rolled into a cold rolled strip having a final thickness. After that, the cold rolled strip of final thickness passes through the annealing furnace which maintains the annealing temperature atmosphere of 810-950 degreeC at the board | substrate speed | rate of 100mpm, and ensures the elongation which satisfies demand. The annealed cold rolled strip then passes continuously through the pickling zone. A cold rolled stainless coil is produced by winding the cold rolled strip having the final thickness passed through the pickling zone in a coil state.

According to the present invention, by cold rolling the pickled hot rolled strip through a tandem rolling mill and Z-Mill without annealing, cold rolling having good surface quality through cost reduction effect due to process shortening and maximizing the production efficiency of the rolling mill. The strip can be produced.

The foregoing is merely illustrative of preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. It must be recognized.

Claims (7)

An apparatus for manufacturing a hot rolled stainless coil made of a cold rolled stainless coil provided by winding a pickled hot rolled strip without annealing, A first rolling facility for primary cold rolling of the hot rolled strip provided by unwinding the hot rolled stainless coil and winding with a first cold rolled coil; A second rolling facility for secondary cold rolling of the first cold rolling strip provided by unwinding the first cold rolling coil and winding with a second cold rolling coil; An annealing pickling facility for annealing and winding the second cold rolling strip provided by unwinding the second cold rolling coil, In the first rolling facility, the hot rolled strip is cold rolled at a reduction ratio of 50 to 60%, and in the second rolling facility, the first cold rolled strip is cold rolled at a reduction ratio of 40 to 50%, and the second cold rolling Strip is a cold rolled stainless steel coil manufacturing apparatus, characterized in that passing through the annealing pickling facility at a plate speed of 90 ~ 110mpm. The method of claim 1, The first rolling equipment is provided with a first rolling mill contacting the surface of the strip and including a work roll having a diameter of 410 ~ 430 mm, the second rolling equipment is in contact with the surface of the strip and has a diameter of 90 ~ 110 mm Cold rolling stainless coil manufacturing apparatus characterized by comprising a second rolling mill including a work roll. The method of claim 2, The first rolling equipment is provided with a plurality of first rolling mill of the stand, the second rolling equipment is a cold rolling stainless steel coil manufacturing apparatus, characterized in that provided with a second stand of a single stand. The method of claim 1, The annealing pickling equipment further comprises a calibration line for correcting the deformation of the annealing pickled strips. The method according to claim 1 or 4, The annealing pickling facility further comprises a defect inspection apparatus for detecting a surface defect of the strip. The method of claim 1, The annealing pickling facility is a cold rolled stainless steel coil manufacturing apparatus comprising an annealing furnace which is maintained in an annealing temperature atmosphere of 850 ~ 950 ℃. delete

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