阅读说明：本技术 五机架六辊连轧机消除超纯铁素体不锈钢轧制色差的方法 (Method for eliminating rolling chromatic aberration of ultrapure ferrite stainless steel by five-rack six-roller continuous rolling mill ) 是由 付金柱 刘春来 段秀峰 武敏 王月省 张良 赵晖 石育帆 郭晓雷 延强 于 2021-08-20 设计创作，主要内容包括：本发明属于不锈钢冷轧制造技术领域,具体涉及一种五机架六辊连轧机消除超纯铁素体不锈钢轧制色差的方法。本发明的一种五机架六辊连轧机消除超纯铁素体不锈钢轧制色差的方法,包括：采用双阶梯式的分配方式控制第一机架至第五机架的变形率；使第一机架至第五机架间的单位张力逐渐增大。本发明的五机架六辊连轧机消除超纯铁素体不锈钢轧制色差的方法,不锈钢轧制过程稳定,带钢表面色泽均匀,不产生轧制色差缺陷,最终产品表面色泽均匀。(The invention belongs to the technical field of stainless steel cold rolling manufacturing, and particularly relates to a method for eliminating rolling chromatic aberration of ultrapure ferrite stainless steel by a five-stand six-roller continuous rolling mill. The invention discloses a method for eliminating rolling chromatic aberration of ultrapure ferrite stainless steel by a five-stand six-roller continuous rolling mill, which comprises the following steps of: controlling the deformation rate of the first frame to the fifth frame by adopting a double-step distribution mode; the unit tension between the first frame and the fifth frame is gradually increased. The method for eliminating the rolling color difference of the ultrapure ferrite stainless steel by the five-stand six-roller continuous rolling mill has the advantages that the rolling process of the stainless steel is stable, the surface color of the strip steel is uniform, the rolling color difference defect is not generated, and the surface color of the final product is uniform.)

1. A method for eliminating rolling chromatic aberration of ultra-pure ferritic stainless steel by a five-stand six-roller continuous rolling mill is characterized by comprising the following steps:

controlling the deformation rate of the first frame to the fifth frame by adopting a double-step distribution mode;

the unit tension between the first frame and the fifth frame is gradually increased.

2. The method for eliminating rolling color difference of ultra-pure ferritic stainless steel by a five-stand six-roll continuous rolling mill according to claim 1, characterized in that the double-step distribution mode comprises: and controlling the deformation rates of the first frame and the third frame to be reduced in sequence, wherein the deformation rate of the fourth frame is greater than that of the third frame, and the deformation rate of the fifth frame is less than that of the fourth frame.

3. The method for eliminating rolling color difference of ultra-pure ferritic stainless steel of claim 2 characterized in that the deformation rate of the fourth stand is 1.5% -3% greater than the deformation rate of the third stand.

4. The method for eliminating rolling color difference of ultra-pure ferritic stainless steel by a five-stand six-roll continuous rolling mill according to any one of claims 1 to 3, characterized in that the deformation ratios of the first stand to the fifth stand are in the following order: 20% -34%, 18% -32%, 17% -27%, 18% -30% and 17% -28%.

5. The method for eliminating rolling color difference of ultra-pure ferritic stainless steel by a five-stand six-roll continuous rolling mill as claimed in claim 1, wherein the unit tension before the first stand is 40-65Mpa, the unit tension between the first stand and the second stand is 145Mpa, the unit tension between the second stand and the third stand is 185Mpa, the unit tension between the third stand and the fourth stand is 180Mpa, the unit tension between the fourth stand and the fifth stand is 175-.

6. The method for eliminating rolling color difference of the ultra-pure ferritic stainless steel by the five-stand six-roll continuous rolling mill according to claim 1, characterized in that the roughness of the working rolls of the first stand to the fifth stand is 0.5-0.8 μm, 0.35-0.45 μm and 0.15-0.25 μm in sequence.

7. The method for eliminating rolling color difference of ultra-pure ferritic stainless steel by using a five-stand six-roll continuous rolling mill as claimed in claim 1, wherein the roll neck of the working roll of the five-stand six-roll continuous rolling mill is 420-470 mm.

8. The method of eliminating rolling color difference of ultrapure ferritic stainless steel according to claim 1, wherein the steel grade of ultrapure ferritic stainless steel comprises: 439M, SUS436L, 441, TTS 443M.

9. The method of eliminating rolling color difference of ultra pure ferritic stainless steel of claim 1 wherein the total deformation rate of the ultra pure ferritic stainless steel is > 70%.

Technical Field

The invention belongs to the technical field of stainless steel cold rolling manufacturing, and particularly relates to a method for eliminating rolling chromatic aberration of ultrapure ferrite stainless steel by a five-stand six-roller continuous rolling mill.

Background

The stainless steel cold-rolled strip steel is subjected to steelmaking and hot rolling in the front process, and then is subjected to cold rolling to obtain a final product. Most ferritic stainless steel can be cold-rolled by adopting a six-roller continuous rolling mill, and generally adopts five frames, so that the method has the advantage of high production efficiency.

Because the ultra-pure ferritic stainless steel has extremely low C, N content (generally [ C + N ] is less than or equal to 250ppm), a certain amount of stabilizing elements Ti and Nb are added, the Cr content is 15-25%, and alloying elements such as Mo and the like can also be added, the ultra-pure ferritic stainless steel has higher strength and larger rolling force required during cold rolling compared with the common low-chromium ferritic stainless steel.

A six-high continuous rolling mill is a mainstream rolling mill type for producing cold-rolled products of ferritic stainless steel, and the roll diameter of the working rolls is generally larger than that of a multi-high rolling mill, so that good plate shapes can be obtained, but the total rolling force is also higher. Taking the five-stand six-roll continuous rolling mill with the working roll diameter of 420-470mm as an example, when the total deformation rate of five stands is more than 70%, the deformation rate and the rolling force distribution of individual stands are large, and rolling color difference is easy to generate when the transverse rolling force distribution is uneven, especially three stands. The color difference band with alternate light and shade is formed on the surface of the strip steel, and the defect cannot be eliminated through subsequent annealing and acid washing, so that the surface quality of the final product is influenced.

Disclosure of Invention

The invention provides a method for eliminating rolling chromatic aberration of ultrapure ferrite stainless steel by a five-rack six-roller continuous rolling mill, aiming at solving the defect of the rolling chromatic aberration produced when the ultrapure ferrite stainless steel is rolled by the five-rack six-roller continuous rolling mill and improving the surface quality of a final product.

Specifically, the method for eliminating rolling color difference of the ultrapure ferrite stainless steel by the five-stand six-roller continuous rolling mill comprises the following steps:

controlling the deformation rate of the first frame to the fifth frame by adopting a double-step distribution mode;

the unit tension between the first frame and the fifth frame is gradually increased.

The method for eliminating rolling color difference of the ultrapure ferrite stainless steel by the five-stand six-roller continuous rolling mill comprises the following two-step distribution mode: and controlling the deformation rates of the first frame and the third frame to be reduced in sequence, wherein the deformation rate of the fourth frame is greater than that of the third frame, and the deformation rate of the fifth frame is less than that of the fourth frame.

According to the method for eliminating rolling chromatic aberration of the ultra-pure ferritic stainless steel by the five-stand six-roller continuous rolling mill, the deformation rate of the fourth stand is 1.5% -3% greater than that of the third stand.

According to the method for eliminating the rolling chromatic aberration of the ultra-pure ferrite stainless steel by the five-stand six-roller continuous rolling mill, the deformation rates of the first stand to the fifth stand sequentially range from: 20% -34%, 18% -32%, 17% -27%, 18% -30% and 17% -28%.

The method for eliminating the rolling color difference of the ultra-pure ferrite stainless steel by the five-rack six-roller continuous rolling mill comprises the steps that the unit tension before the first rack is 40-65MPa, the unit tension between the first rack and the second rack is 145MPa, the unit tension between the second rack and the third rack is 185MPa, the unit tension between the third rack and the fourth rack is 180MPa, the unit tension between the fourth rack and the fifth rack is 175 MPa 205MPa, and the unit tension after the fifth rack is 190 MPa 230 MPa.

According to the method for eliminating rolling color difference of the ultra-pure ferritic stainless steel by the five-stand six-roller continuous rolling mill, the roughness of the working rollers from the first stand to the fifth stand is 0.5-0.8 mu m, 0.35-0.45 mu m and 0.15-0.25 mu m in sequence.

According to the method for eliminating the rolling chromatic aberration of the ultra-pure ferritic stainless steel by the five-stand six-roller continuous rolling mill, the roll neck of the working roll of the five-stand six-roller continuous rolling mill is 420-470 mm.

The method for eliminating rolling chromatic aberration of the ultrapure ferritic stainless steel by the five-stand six-roller continuous rolling mill comprises the following steps: 439M, SUS436L, 441, TTS 443M.

According to the method for eliminating rolling chromatic aberration of the ultrapure ferrite stainless steel by the five-stand six-roller continuous rolling mill, the total deformation rate of the ultrapure ferrite stainless steel is more than 70%.

The technical scheme of the invention has the following beneficial effects:

the method for eliminating the rolling color difference of the ultrapure ferrite stainless steel by adopting the five-stand six-roller continuous rolling mill has the advantages of stable stainless steel rolling process, uniform strip steel surface color, no rolling color difference defect and uniform final product surface color.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention. The process of the present invention employs conventional methods or apparatus in the art, except as described below. The following noun terms have meanings commonly understood by those skilled in the art unless otherwise specified.

The terms "first," "second," and the like, as used herein do not denote any order or importance, but rather are used to distinguish one element from another, and the terms "the," "one," and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. In addition, all ranges disclosed herein are inclusive of the endpoints and independently combinable.

Specifically, the method for eliminating rolling color difference of the ultrapure ferrite stainless steel by the five-stand six-roller continuous rolling mill comprises the following steps:

controlling the deformation rate of the first frame to the fifth frame by adopting a double-step distribution mode;

the unit tension between the first frame and the fifth frame is gradually increased.

According to the method for eliminating the rolling chromatic aberration of the ultra-pure ferrite stainless steel by the five-rack six-roller continuous rolling mill, disclosed by the invention, the rolling chromatic aberration of the ultra-pure ferrite stainless steel can be eliminated and the surface quality of a final product is improved by controlling the deformation rate, unit tension and the change trend of the roughness of the working roller from the first rack to the fifth rack.

In some preferred embodiments, the method for eliminating rolling color difference of the ultrapure ferritic stainless steel by the five-stand six-roller continuous rolling mill comprises the following steps:

(1) And controlling the deformation rate of the first frame to the fifth frame by adopting a double-step distribution mode.

Preferably, the dual-step distribution manner includes: and controlling the deformation rates of the first frame and the third frame to be reduced in sequence, wherein the deformation rate of the fourth frame is greater than that of the third frame, and the deformation rate of the fifth frame is less than that of the fourth frame.

Preferably, the deformation rate of the fourth stand is 1.5-3 percentage points greater than that of the third stand, so that the rolling loads of the second stand and the third stand can be effectively reduced, the work hardening characteristics of the ultra-pure ferritic stainless steel are effectively utilized, the rolling pressures of the latter stands are approximately equal, and the color difference caused by the large rolling pressure of some stands is reduced.

When the deformation rate of the fourth stand is larger than that of the third stand by less than 1.5%, the second stand, the third stand and particularly the third stand are easy to generate color difference due to large rolling pressure; when the deformation ratio of the fourth stand is greater than the deformation ratio of the third stand by more than 3%, the fourth and fifth stands, particularly the fourth stand, are liable to cause color difference due to large rolling pressure.

Further preferably, the deformation ratios of the first frame to the fifth frame sequentially range from: 20% -34%, 18% -32%, 17% -27%, 18% -30% and 17% -28%.

In practice, when the range of the deformation ratio of the first to fifth stands is out of the above range of the present invention, it is easy to cause color difference of one or some stands due to excessive rolling load.

Wherein the total deformation rate of the ultra-pure ferritic stainless steel is more than 70 percent.

The existing deformation ratio distribution decreases gradually from the first stand to the last stand due to the work hardening effect of the metal rolling process. In the process of rolling the ultrapure ferrite stainless steel, the rolling chromatic aberration is easily generated due to the large rolling force of the middle frame. According to the invention, the deformation rate from the first frame to the fifth frame is controlled by adopting a double-step distribution mode, so that rolling chromatic aberration caused by large rolling force can be well avoided.

(2) The unit tension between the first frame and the fifth frame is gradually increased.

The tension setting among the frames adopts unit tension setting, the total tension (except before the first frame) is reduced in sequence along with the reduction of the thickness of each frame, and the unit tension is gradually increased.

The rolling load (rolling force) can be reduced by large rolling tension, but the rolling load is too large, so that slipping is caused to generate color difference, and accidents are caused by instability of the rolling process seriously. An excessively low rolling tension inevitably leads to a color difference corresponding to an increase in rolling force. The tension between the stands should therefore be matched to the rolling force of the corresponding deformation ratio. The following reasonable tension setting ranges are obtained through continuous experiments:

The unit tension in front of the first rack is 40-65MPa, the unit tension between the first rack and the second rack is 145MPa, the unit tension between the second rack and the third rack is 185MPa, the unit tension between the third rack and the fourth rack is 180MPa, the unit tension between the fourth rack and the fifth rack is 175-205MPa, and the unit tension behind the fifth rack is 230MPa and 190-145 MPa.

In a preferred embodiment, the unit tension before the first rack is 40-65Mpa, the unit tension between the first rack and the second rack is 100-.

Through practice, when the unit tension between the first frame and the fifth frame is not within the protection range of the invention, when the tension is too small, the front slip value is too small, so that the slip is generated, and when the tension is too large, the belt breakage accident is easily generated.

(3) And controlling the roughness of the working rolls of the first frame to the fifth frame.

The influence rule of the roughness of the working roll is as follows: the smaller roughness of the working roll can reduce the rolling pressure, but the smaller roughness can cause slippage; the larger roughness of the working roll causes the rolling pressure to increase, but the rolling process is more stable, but the color difference is generated due to the larger rolling pressure. Therefore, the roughness of the roller should be matched with the rolling force of the corresponding deformation rate, so that the rolling process is stable, and the surface color of the rolled material is uniform.

The first and second frames adopt larger work roll roughness, and can implement large deformation amount on the rolling material which is not obviously hardened so as to avoid slipping. The rolled materials of the third and fourth frames reach a certain hardening degree, the surface roughness is correspondingly reduced, stable rolling is realized, slipping is avoided, and the corresponding roughness of the working roll is also reduced. The fifth frame is matched with a smaller working roll roughness, a smaller deformation rate and a corresponding smaller rolling force, so that a smoother strip steel surface and a smoother plate type can be obtained. The following reasonable roughness setting ranges of the working roll are obtained through continuous tests:

the roughness of the working rolls from the first frame to the fifth frame is 0.5-0.8 μm, 0.35-0.45 μm and 0.15-0.25 μm in sequence.

Optionally, the roll neck of the working roll of the five-stand six-roll continuous rolling mill is 420-470 mm.

Alternatively, the steel grades of the ultra pure ferritic stainless steel include, but are not limited to: 439M, SUS436L, 441, TTS443M, and the like.

Examples

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. Experimental procedures without specifying specific conditions in the following examples were carried out according to conventional methods and conditions.

Example 1

The continuous rolling mill is a five-stand six-roller continuous rolling mill with the working roller diameter of 420-470 mm. The thickness of the raw material is 2.84mm, the width is 439M of 1436mm, and the rolling target thickness is 0.74 mm.

(1) Deformation ratio distribution

The deformation rates of the No. 1-5 frames are controlled to be 28.3%, 25.3%, 20.8%, 22.1% and 21.3%.

(2) Tension setting

The unit tension of the front part of the No. 1 frame, the middle part of the No. 2 frame, the middle part of the No. 3 frame, the middle part of the No. 4 frame and the No. 5 frame is set to be 60MPa, 134MPa, 162MPa, 179MPa, 193MPa and 205 MPa.

(3) Roughness of work roll

The roughness of the 1-5# frame working roll is as follows: 0.67 μm, 0.56 μm, 0.42 μm, 0.39 μm, 0.21. mu.m.

The rolling process is stable, the surface color of the strip steel is uniform, and the rolling color difference is eliminated.

Example 2

The continuous rolling mill is a five-stand six-roller continuous rolling mill with the working roller diameter of 420-470 mm. SUS436L having a raw material thickness of 2.87mm and a width of 1575mm and a rolled target thickness of 0.55 mm.

(1) Deformation ratio distribution

The deformation rates of the No. 1-5 frames are controlled to be 31.6%, 29.4%, 24.9%, 27.8% and 27.1%.

(2) Tension setting

The unit tensions of the front part of the No. 1 frame, the between the No. 1 frame and the No. 2 frame, the between the No. 2 frame and the No. 3 frame, the between the No. 3 frame and the No. 4 frame, the between the No. 4 frame and the No. 5 frame and the rear part of the No. 5 frame are set to be 57MPa, 133MPa, 159MPa, 175MPa, 189MPa and 201 MPa.

(3) Roughness of work roll

The roughness of the 1-5# frame working roll is as follows: 0.66 μm, 0.54 μm, 0.39 μm, 0.41 μm, 0.19 μm.

The rolling process is stable, the surface color of the strip steel is uniform, and the rolling color difference is eliminated.

Example 3

The continuous rolling mill is a five-stand six-roller continuous rolling mill with the working roller diameter of 420-470 mm. The thickness of the raw material is 3.42mm, the width of the raw material is 1252mm, and the rolling target thickness is 0.92 mm.

(1) Deformation ratio distribution

The deformation rates of the No. 1-5 frames are controlled to be 28.2%, 24.0%, 20.3%, 22.6% and 20.0%.

(2) Tension setting

The unit tension before the No. 1 frame, between the No. 1 and 2 frames, between the No. 2 and 3 frames, between the No. 3 and 4 frames, between the No. 4 and 5 frames and behind the No. 5 frame is set to be 57MPa, 120MPa, 140MPa, 160MPa, 185MPa and 215 MPa.

(3) Roughness of work roll

The roughness of the 1-5# frame working roll is as follows: 0.68 μm, 0.58 μm, 0.40 μm, 0.43 μm, 0.17 μm.

The rolling process is stable, the surface color of the strip steel is uniform, and the rolling color difference is eliminated.

Comparative example 1

The continuous rolling mill is a five-stand six-roller continuous rolling mill with the working roller diameter of 420-470 mm. SUS436L having a raw material thickness of 2.88mm and a width of 1565mm and a rolling target thickness of 0.55 mm.

The deformation ratio distribution is according to a conventional decreasing distribution:

the deformation rates of the No. 1-5 frames are controlled to be 34.6%, 29.3%, 27.6%, 26.6% and 22.0%.

The total rolling force of the No. 3 machine frame exceeds 16500KN, which causes uneven transverse distribution of pressure and color difference defect.

The present invention has been disclosed in the foregoing in terms of preferred embodiments, but it will be understood by those skilled in the art that these embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention. It should be noted that all changes and substitutions that are equivalent to these embodiments are deemed to be within the scope of the claims of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined in the claims.