TW201540386A - Method for eliminating edge mark of continuous cold rolling mill - Google Patents

Abstract

A method for eliminating edge marks of a continuous cold rolling mill is described, which is suitable for at eliminating a plurality of edge marks on two back up rollers in a second last cold rolling station of a plurality of cold rolling stations of the continuous cold rolling mill. The method for eliminating the edge marks of the continuous cold rolling includes the following steps. Two old work rollers in the second last cold rolling station are replaced with two chromium plating work rollers. Each of chromium plating work rollers includes a base and a chromium film coating a surface of the base. A cold rolling treatment is performed on a steel band by using the chromium plating work rollers and the back up rollers to simultaneously perform a planarization treatment by using the chromium plating work rollers and the back up rollers.

Description

Method for eliminating edge roll marks of continuous cold rolling mill

This invention relates to a continuous cold rolling technique and, more particularly, to a method of eliminating edge roll marks in a continuous cold rolling mill.

In the steelmaking process, a five-station-four-roll continuous cold rolling mill is used to produce cold-rolled steel coils. Please refer to FIG. 1 , which is a schematic diagram of a device of a continuous cold rolling mill. This continuous cold rolling mill 100 comprises five cold rolling stations 102, 104, 106, 108 and 110. These cold rolling stations 102, 104, 106, 108 and 110 each have a configuration of a four-roller. That is, the cold rolling station 102 has a pair of work rolls 112a and 112b, and a pair of back rolls 114a and 114b sandwiching the work rolls 112a and 112b; the cold rolling stand 104 has a pair of work rolls 116a and 116b sandwiching the pair Back rolls 118a and 118b of work rolls 116a and 116b; cold roll station 106 has a pair of work rolls 120a and 120b, and a pair of back rolls 122a and 122b sandwiching work rolls 120a and 120b; cold rolling station 108 has a pair of work Rollers 124a and 124b, and a pair of back rolls 126a and 126b sandwiching the work rolls 124a and 124b; and the cold rolling stand 110 has a pair of work rolls 128a and 128b, and a pair of back rolls 130a sandwiching the work rolls 128a and 128b. With 130b.

The continuous cold rolling mill 100 mainly utilizes the four-rolled rolls of these cold rolling stations 102, 104, 106, 108 and 110 to heat the thickened steel strip 140 after hot rolling. Roll to the thickness of the finished product of the steel strip 140 required by the customer. When cold rolling of the steel strip 140 is carried out by the continuous cold rolling mill 100, the steel strip 140 is introduced by the first cold rolling station 102, and is sequentially rolled by the four rolls of the cold rolling stations 102, 104, 106, 108 and 110. Thereafter, the thicker steel strip 140 can be rolled into a steel strip 140 having a desired thickness. Generally, in the production process, the continuous cold rolling mill 100 is sequentially produced from a wide to narrow steel strip 140. That is, according to the width of the steel strip 140 to be cold-rolled, it is cold-rolled in a wide and narrow order.

Please refer to FIG. 2A to FIG. 2C together, which is a schematic diagram showing the formation mechanism of the edge roll marks of the continuous cold rolling mill. Here, the fourth cold rolling station 108 of Fig. 1 is used to illustrate the formation mechanism of the edge roll marks. As shown in Fig. 2A, during the cold rolling process, the positions where the rolls 124a and 124b and the edges of the steel strip 140a contact each other leave the edge roll marks 142a and 142b caused by the edges of the steel strip 140a, respectively, and the work rolls 124a and The edge roll marks 142a and 142b on 124b are transferred to the back rolls 126a and 126b which are in contact therewith to form edge roll marks 142c and 142d, respectively. The steel strip 140a is a steel strip having a large width. As shown in Fig. 2B, as the width of the cold-rolled steel strip 140b is reduced, that is, the width of the steel strip 140b which is cold-rolled after the steel strip 140a is smaller than the width of the steel strip 140a, the work rolls 124a and 124b and the steel strip 140b The edge contact locations will also leave the edge roll marks 144a and 144b caused by the steel strip 140b, respectively, and the edge roll marks 144a and 144b on the work rolls 124a and 124b will be further transferred to the back rolls 126a and 126b. Edge roll marks 144c and 144d are formed. Since the width of the steel strip 140b is smaller than the width of the steel strip 140a, the edge roll marks 144a, 144b, 144c and 144d formed on the rolls 124a and 124b and the back rolls 126a and 126b, respectively, are located in the shape of the steel strip 140a. The inner side of the edge marks 142a, 142b, 142c and 142d are formed. The longer the contact time between the rolls 124a and 124b and the steel strips 140a and 140b, the more pronounced these edge roll marks 142a, 142b, 142c, 142d, 144a, 144b, 144c and 144d.

As shown in Fig. 2C, when the steel strip 140c which is subsequently cold rolled is wider than the steel strips 140a and 140b, the edge rolls 142a and 144a, 142b and 144b, 142c on the rolls 124a and 124b and the back rolls 126a and 126b. And 144c, and 142d and 144d are transferred to the steel strip 140c, and edge roll marks 146 and 148 are formed on the steel strip 140c. Therefore, it is common practice to replace the old work rolls 124a and 124b with a pair of new work rolls before cold rolling the wider steel strip 140c, but during the rolling of the steel strip 140c, the back rolls 126a and 126b The upper edge roll marks 142c and 144c and 142d and 144d are transferred to a new work roll, which also leaves edge roll marks 146 and 148 on the steel strip 140c.

In order to improve the problem of the edge roll marks of the steel strip, conventionally, when the rolled steel strip is converted from a narrow sheet to a wide sheet, the work rolls 124a of the fourth cold rolling station 108 are replaced by a set of high-roughness work rolls. With 124b, the set of high-roughness work rolls are used to grind the back rolls 126a and 126b to eliminate the edge roll marks 142c and 144c, and 142d and 144d on the back rolls 126a and 126b, respectively.

In such an improvement, the steel strip being cold-rolled is first cut off, and the old work rolls 124a and 124b are withdrawn, then a high-roughness work roll is set, and the set of high-roughness work rolls is used to grind the back roll 126a. With 126b. The grinding time lasts approximately 20 minutes to 40 minutes until the back rolls 126a and 126b The upper edge roll marks 142c and 144c, and 142d and 144d disappear. Even if the edge roller marks 142c and 144c, and 142d and 144d on the back rolls 126a and 126b cannot be removed after grinding, the back rolls 126a and 126b need to be replaced.

However, cutting the steel strip will result in a loss of weight of the steel strip. Secondly, in addition to the time it takes to grind the back roll, it takes more than one hour to cut the steel strip and re-wear the strip. This will make the steel strip to be cold-rolled too long in the pickling tank and have excessive acidity. The problem of washing, which in turn causes the weight loss of the steel strip, and even the loss of product rejection. Furthermore, this practice consumes a set of high-roughness work rolls and even replaces the back rolls, resulting in a significant increase in cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for eliminating the edge roll marks of a continuous cold rolling mill which directly replaces the old work with a chrome-plated work roll when the cold rolling process is converted from a narrow strip steel strip to a wide strip steel strip. The roll can be used to flatten the surface of the back roll while continuously cold rolling the steel strip, thereby eliminating the edge roll marks of the back roll of the continuous cold rolling mill.

Another object of the present invention is to provide a method for eliminating the edge roll marks of a continuous cold rolling mill, which can effectively eliminate the edge roll marks of the back roll of the continuous cold rolling mill without cutting the steel strip, thereby avoiding the steel strip Loss.

It is a further object of the present invention to provide a method of eliminating edge roll marks in a continuous cold rolling mill which reduces downtime and thus avoids weight and product rejection losses of the steel strip due to excessive pickling.

It is still another object of the present invention to provide a method of eliminating the edge roll marks of a continuous cold rolling mill without consuming a set of high-roughness work rolls or The back roll needs to be replaced, thus reducing the cost of the cold rolling process.

According to the above object of the present invention, there is provided a method for eliminating edge roll marks of a continuous cold rolling mill, which is suitable for eliminating at least a plurality of two back rolls of a penultimate cold rolling station in a plurality of cold rolling stations of a continuous cold rolling mill Edge roll marks. This method of eliminating the edge roll marks of a continuous cold rolling mill comprises the following steps. The two old work rolls of the penultimate cold rolling station are replaced by two chrome-plated work rolls, wherein each chrome roll comprises a substrate and a chrome film coated on the surface of the substrate. The steel strips are cold-rolled by these chrome-plated rolls and back rolls to simultaneously flatten the back rolls using these chrome-plated rolls.

According to an embodiment of the invention, the material of the substrate of each of the chrome-plated rolls is the same as the material of the old work rolls.

According to another embodiment of the present invention, the thickness of the chromium film of each of the chrome-plated rolls is from 8 μm to 12 μm.

According to still another embodiment of the present invention, each of the chrome-plated rolls has a surface roughness of from 0.3 μm to 0.6 μm.

According to still another embodiment of the present invention, the flattening process described above includes a lapping process.

100‧‧‧Continuous cold rolling mill

102‧‧‧ Cold Rolling Station

104‧‧‧ Cold Rolling Station

106‧‧‧ Cold Rolling Station

108‧‧‧ Cold Rolling Station

110‧‧‧ Cold Rolling Station

112a‧‧‧Work rolls

112b‧‧‧Work rolls

114a‧‧‧Back roll

114b‧‧‧Back roll

116a‧‧‧Working rolls

116b‧‧‧Work rolls

118a‧‧‧Back roll

118b‧‧‧Back roll

120a‧‧‧Working rolls

120b‧‧‧Work rolls

122a‧‧‧Back roll

122b‧‧‧Back roll

124a‧‧‧Working rolls

124b‧‧‧Work rolls

126a‧‧‧Back roll

126b‧‧‧Back roll

128a‧‧‧Working rolls

128b‧‧‧Work rolls

130a‧‧‧Back roll

130b‧‧‧Back roll

140‧‧‧ steel strip

140a‧‧‧ steel strip

140b‧‧‧ steel strip

140c‧‧‧ steel strip

142a‧‧‧Edge roll marks

142b‧‧‧Edge roll marks

142c‧‧‧Edge roll marks

142d‧‧‧Edge roll marks

144a‧‧‧Edge roll marks

144b‧‧‧Edge roll marks

144c‧‧‧ edge roll marks

144d‧‧‧Edge roll marks

146‧‧‧ edge roll marks

148‧‧‧Edge roll marks

200‧‧‧ method

202‧‧‧Steps

204‧‧‧Steps

300‧‧‧Continuous cold rolling mill

302‧‧‧ Cold Rolling Station

304‧‧‧ Cold Rolling Station

306‧‧‧ Cold Rolling Station

308‧‧‧ Cold Rolling Station

310‧‧‧ Cold Rolling Station

312a‧‧‧Working rolls

312b‧‧‧Working rolls

314a‧‧‧Back roll

314b‧‧‧Back roll

316a‧‧‧Working rolls

316b‧‧‧Working rolls

318a‧‧‧Back roll

318b‧‧‧Back roll

320a‧‧‧Working rolls

320b‧‧‧Work rolls

322a‧‧‧Back roll

322b‧‧‧Back roll

324a‧‧‧Working rolls

324b‧‧‧Work rolls

326a‧‧‧Back roll

326b‧‧‧Back roll

328a‧‧‧Working rolls

328b‧‧‧Working rolls

330a‧‧‧Back roll

330b‧‧‧Back roll

332‧‧‧ steel strip

334‧‧‧Edge roll marks

336a‧‧‧chrome roller

336b‧‧‧chrome roller

338‧‧‧Substrate

340‧‧‧Chromium film

342‧‧‧ surface

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

2A to 2C are schematic views showing the formation mechanism of the edge roll marks of the continuous cold rolling mill.

3 is a flow chart showing a method of eliminating edge roll marks of a continuous cold rolling mill in accordance with an embodiment of the present invention.

4 is a schematic view of a device of a continuous cold rolling mill in accordance with an embodiment of the present invention.

Figure 5 is a schematic view of a device of a penultimate station of a continuous cold rolling mill in accordance with an embodiment of the present invention.

Please refer to FIG. 3 to FIG. 5 , which are respectively a flow chart of a method for eliminating edge roll marks of a continuous cold rolling mill, a device schematic diagram of a continuous cold rolling mill, and a schematic diagram according to an embodiment of the present invention. Schematic diagram of the device from the penultimate station of the continuous cold rolling mill. In the present embodiment, the method 200 for eliminating the edge roll marks of a continuous cold rolling mill can be applied to a five-station-four-roll continuous cold rolling mill, such as the continuous cold rolling mill 300 shown in FIG. 4, to eliminate continuous cold. The edge of the rolling mill 300 is marked by a roll.

In some embodiments, as shown in FIG. 4, the continuous cold rolling mill 300 includes five cold rolling stations 302, 304, 306, 308, and 310, and these cold rolling stations 302, 304, 306, 308, and 310 are along the steel. The rolling direction of the belt 332 is sequentially arranged. Each of the cold rolling stations 302, 304, 306, 308 and 310 is a four-roller design. Wherein, the cold rolling station 302 has a pair of back rolls 314a and 314b, and a pair of work rolls 312a and 312b sandwiched between the pair of back rolls 314a and 314b; the cold rolling stand 304 has a pair of back rolls 318a and 318b, and a pair of work rolls 316a and 316b sandwiched between the pair of back rolls 318a and 318b; the cold rolling stand 306 has a pair of back rolls 322a and 322b, and a pair of work rolls sandwiched between the pair of back rolls 322a and 322b 320a and 320b; cold rolling station 308 has a pair of back rolls 326a and 326b, and a pair of work rolls 324a and 324b sandwiched between the pair of back rolls 326a and 326b; and a cold rolling stand 310 having a pair of back rolls 330a and 330b and sandwiching the back rolls 330a and 330b A pair of work rolls 328a and 328b.

When the steel strip 332 is cold rolled by the continuous cold rolling mill 300, the thicker steel strip 332 is sequentially rolled through the four rolls of the cold rolling stations 302, 304, 306, 308 and 310 to form the desired thickness. Finished steel strip. At the time of rolling, each station is in direct contact with the steel strip 332 by a work roll. As shown in Fig. 4, taking the first cold rolling station 302 as an example, the back rolls 314a and 314b are joined to the adjacent work rolls 312a and 312b, respectively. Moreover, as the steel strip 332 is rolled downstream, the driven rollers 312a and 312b are rotated in the counterclockwise and clockwise directions, respectively, and the work rolls 312a and 312b respectively drive the back rolls 314a and 314b engaged therewith in a clockwise manner. Turn counterclockwise.

When the continuous cold rolling mill 300 rolls the steel strip 332, the edges of the steel strip 332 are directly and indirectly at the work rolls 312a and 312b, 316a and 316b, 320a and 320b of the respective cold rolling stations 302, 304, 306, 308 and 310. , 324a and 324b and 328a and 328b, and back rolls 314a and 314b, 318a and 318b, 322a and 322b, 326a and 326b, and 330a and 330b cause edge roll marks. As shown in FIG. 5, taking the penultimate station, that is, the fourth cold rolling station 308 as an example, after cold rolling the steel strips 332 of different widths, the back rolls 326a are formed with a plurality of strips caused by the edges of the steel strips 332. Edge roll marks 334. The method 200 of the present embodiment for eliminating the edge roll marks of a continuous cold rolling mill can be used to eliminate edge roll marks on the back rolls of one or more stations or stations. In some embodiments, the method 200 is used to at least eliminate the penultimate of the continuous cold rolling mill 300 The cold rolling station, i.e., the edge roll marks 334 on the back rolls 326a and 326b of the fourth cold rolling station 308.

Referring again to FIGS. 3 through 5, in these embodiments, when the method 200 is performed, first, as described in step 202, the cold rolling of the steel strip 332 is suspended, and the two chrome-plated rollers 336a and 336b are replaced, respectively. Two old work rolls 324a and 324b of the penultimate cold rolling station 308. Wherein, the two old work rolls 324a and 324b have edge roll marks (not shown) caused by the steel strip 332. Further, as shown in FIG. 5, each of the chrome rollers 336a and 336b includes a substrate 338 and a chrome film 340, wherein the chrome film 340 is coated on the surface 342 of the substrate 338. The material of the substrate 338 of each of the chrome rollers 336a and 336b may be the same as the material of the old work rolls 324a and 324b, for example. However, in some examples, the substrate 338 of the chrome rollers 336a and 336b may use a different material than the old rolls 336a and 336b. In some exemplary examples, the chrome film 340 of the chrome-plated rollers 336a and 336b has a thickness of 8 μm to 12 μm. Further, the roughness of the surface of each of the chrome-plated rolls 336a and 336b, that is, the surface of the chrome film 340 is from 0.3 μm to 0.6 μm.

Next, as described in step 204 of FIG. 3, after the cold rolling of the steel strip 332 is temporarily stopped, and the old work rolls 324a and 324b are replaced by the chrome-plated rolls 336a and 336b, respectively, the cold rolling stations 302, 304 are continuously used. Worker rolls 312a and 312b, 316a and 316b, 320a and 320b and 328a and 328b, and back rolls 314a and 314b, 318a and 318b, 322a and 322b and 330a and 330b, and chrome plating at cold rolling station 308 Rollers 336a and 336b, and back rolls 326a and 326b, cold-roll the steel strip 332. Due to the high hardness of the chromium film 338 on the surface of the chrome rollers 336a and 336b, Therefore, when the chrome-plated rolls 336a and 336b are cold-rolled on the steel strip 332, not only the steel strip 332 cannot cause edge roll marks on the chrome-plated rolls 336a and 336b, but also the edge roll marks 334 on the back rolls 326a and 326b cannot be transferred to the chrome. On the membrane 338. Further, since the surfaces of the chrome-plated rolls 336a and 336b have appropriate roughness, the back rolls 326a and 326b which are in contact therewith can be flattened while the steel strip 332 is cold-rolled. After a period of planarization, the edge roll marks 334 on the back rolls 326a and 326b can be effectively eliminated. In some exemplary examples, the tempering of the back rolls 326a and 326b by the chrome rolls 336a and 336b includes grinding the back rolls 326a and 326b with a high hardness and appropriate roughness chrome film 338.

Since the method 200 of the present embodiment only needs to temporarily stop the cold rolling treatment of the steel strip 332 by the continuous cold rolling mill 300, and does not need to cut the steel strip 332, the downtime of the continuous cold rolling mill 300 can be greatly shortened. In an exemplary embodiment, the downtime of the continuous cold rolling mill 300 can be reduced to about 15 minutes from about 60 minutes of the prior art. Also, because the downtime is greatly shortened, the weight loss and product rejection loss of the excessive pickling of the steel strip 332 are not caused. Moreover, the application of the method 200 does not require the loss of a set of high-roughness work rolls, which reduces the cost of the cold rolling process.

In these embodiments, since the reduction rate of the generally final cold rolling station 310 is relatively small, the traces of the edge marks of the first three stations of the cold rolling stations 302, 304 and 306 are transferred onto the steel strip 332. The four cold rolling stations 308 are substantially eliminated after rolling, so these embodiments have chosen to replace the work rolls 324a and 324b of the fourth cold rolling station 308 with chrome rolls 336a and 336b, thereby avoiding cold rolling and continuous cooling. The surface of the steel strip 332 of the rolling mill 300 produces an edge Roll marks. Of course, the method 200 of the present embodiment may also select to replace the old work rolls of the plurality of cold rolling stations with a plurality of sets of chrome-plated work rolls. Moreover, in some exemplary examples, if the edge roll marks appear at the very adjacent side edges of the steel strip 332, the effect on the quality of the steel strip 332 is relatively low, so the method 200 can be used in a continuous cold rolling mill. When the width difference of the plurality of steel strips 332 of 300 cold rolling is greater than 6 mm.

It is obvious from the above embodiments that the method for eliminating the edge roll marks of the continuous cold rolling mill of the present invention is directly chrome-plated roller when the cold rolling process is converted from a narrow strip steel strip to a wide strip steel strip. Instead of the old work rolls, the chrome roll can be used to flatten the surface of the back roll while continuously cold rolling the steel strip, thereby eliminating the edge roll marks of the back roll of the continuous cold rolling mill.

According to the above embodiments, another advantage of the present invention is that the method for eliminating the edge roll marks of the continuous cold rolling mill can effectively eliminate the edge roll marks of the back roll of the continuous cold rolling mill without cutting the steel strip. Avoid causing loss of steel strips.

According to the above embodiments, another advantage of the present invention is that the method for eliminating the edge roll marks of the continuous cold rolling mill can greatly shorten the downtime of the continuous cold rolling mill, thereby avoiding the steel strip being caused by excessive pickling. Weight and product rejection losses.

According to the above embodiments, another advantage of the present invention is that the method for eliminating the edge roll marks of the continuous cold rolling mill does not need to consume a set of high-roughness work rolls, and does not need to replace the back rolls, thereby reducing the cold rolling process. cost.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any person having ordinary knowledge in the technical field does not take off. The scope of the present invention is defined by the scope of the appended claims.

308‧‧‧ Cold Rolling Station

326a‧‧‧Back roll

326b‧‧‧Back roll

332‧‧‧ steel strip

334‧‧‧Edge roll marks

336a‧‧‧chrome roller

336b‧‧‧chrome roller

338‧‧‧Substrate

340‧‧‧Chromium film

342‧‧‧ surface

Claims (5)

A method for eliminating edge roll marks of a continuous cold rolling mill, which is suitable for eliminating at least a plurality of edge roll marks on two back rolls of one of the plurality of cold rolling stations of the continuous cold rolling mill, the elimination The method for the edge roll marks of the continuous cold rolling mill comprises: replacing two old work rolls of the penultimate cold rolling station with two chrome-plating rolls, wherein each of the chrome-plating rolls comprises a substrate and a chrome film a surface of one of the substrates; and a cold rolling treatment of the steel strips with the chrome-plated work rolls and the back rolls to simultaneously planarize the back rolls by the chrome-plated work rolls. A method for eliminating edge roll marks of a continuous cold rolling mill according to claim 1, wherein the material of the substrate of each of the chrome-plated rolls is the same as the material of the old rolls. The method of claim 1, wherein the chromium film of each of the chrome-plated rolls has a thickness of from 8 μm to 12 μm. A method for eliminating edge roll marks of a continuous cold rolling mill according to claim 1, wherein one of the chrome-plated rolls has a surface roughness of from 0.3 μm to 0.6 μm. A method of eliminating edge roll marks of a continuous cold rolling mill as claimed in claim 1, wherein the flattening treatment comprises a grinding treatment.