Production method of thin-gauge medium-high carbon steel

Abstract

The invention relates to the technical field of medium-high carbon thin material rolling, in particular to a production method of thin-gauge medium-high carbon steel. The method comprises the following steps: 1) controlling plate blank charging temperature, preheating section heating temperature and heating tapping temperature; (2) rough rolling is conducted through two or more rolling mills, the first rolling mill is R1, the second rolling mill is R2, and the rolling speed is controlled; (3) rough rolling load is controlled; (4) controlling the load of seven finish rolling mills; (5) the plate shape is controlled through roll bending force; (6) setting the opening degree of a guide ruler of each rolling mill for finish rolling as K, mm; the width of the plate strip is D, mm; sG = K-D, and SG is the allowance value of the guide ruler, mm. According to the method, the rolling stability of the medium-high carbon thin specification can be improved, the clockwise-folding steel clamping and drifting accidents during rolling of the medium-high carbon thin specification are reduced, and the quality and the comprehensive yield of medium-high carbon products are improved.

Description

Technical Field

[0001] The invention relates to the technical field of medium-high carbon thin material rolling, in particular to a production method of thin-gauge medium-high carbon steel. Background Art

[0002] At present, when hot-rolled strip production lines roll thin-gauge medium-high carbon steel products, due to the limitations of the equipment's own capacity and rolling process conditions, as well as the high carbon content of medium-high carbon steel, rolling of thin-gauge medium-high carbon steel products is difficult. During the rolling process, accidents such as head strip folding and tail steel throwing often occur. The most obvious is that during the rolling process, the strip moves in the rolling mill and deviates from the rolling center line, scraping the guide gauge and causing steel jamming accidents. This not only affects the rolling stability of the rolling line, but also reduces product quality and comprehensive yield rate. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a production method for thin-gauge medium-high carbon steel, which can improve the rolling stability of thin-gauge medium-high carbon steel, reduce the accidents of folding and steel jamming and tail swinging during rolling of thin-gauge medium-high carbon steel, and improve the quality of medium-high carbon products and the comprehensive yield rate.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for producing thin-gauge medium-high carbon steel, wherein the thin-gauge refers to a hot-rolled strip steel with a thickness of 1.5 to 3.5 mm, and the medium-high carbon steel refers to a carbon steel with a carbon mass content of 0.25% to 0.6%, specifically comprising the following steps:

[0006] 1) The slab charging temperature is controlled at 350-700℃, the heating temperature in the preheating section is controlled at 700-850℃; the heating out of the furnace temperature is controlled at 1240-1260℃;

[0007] 2) Rough rolling is carried out by two or more rolling mills, the first rolling mill is R1, the second rolling mill is R2, the first rolling speed of R1 is 1.8-2.2 m / s, the second rolling speed is 2.2-2.5 m / s, and the third rolling speed is 2.3-2.6 m / s;

[0008] R2 The first rolling speed is 3.1-3.5 m / s, the second rolling speed is 4.0-4.5 m / s, and the third rolling speed is 4.1-4.6 m / s;

[0009] 3) R1 The first pass load is 20% to 22%, the second pass load is 17% to 22%, and the third pass load is 13% to 16%;

[0010] 4) Finish rolling is carried out by more than seven rolling mills, the first rolling mill is F1, the second rolling mill is F2, the third rolling mill is F3, the fourth rolling mill is F4, the fifth rolling mill is F5, the sixth rolling mill is F6, and the seventh rolling mill is F7;

[0011] Load distribution: F1 is 30% to 42%, F2 is 30% to 41%, F3 is 10% to 18%, F4 is 5% to 10%, F5 is 2% to 6%, F6 is 1.5% to 5%, F7 is 1.2% to 1.8%;

[0012] 5) Control the plate shape by bending roller force, control the F1 bending roller force to 750-1000KN, the F2 bending roller force to 700-950KN, the F3 bending roller force to 600-900KN, the F4 bending roller force to 500-800KN, the F5 bending roller force to 440-750KN, the F6 bending roller force to 400-700KN, and the F7 bending roller force to 330-650KN;

[0013] 6) Set the guide opening of each stand of the finishing rolling mill to K, mm; the strip width to D, mm;

[0014] Then △SG=KD, △SG is the guide ruler allowance value, mm.

[0015] Furthermore, in step 1), the thickness of the raw material slab is 170 to 230 mm.

[0016] Furthermore, in step 1), the preheating time of the heating furnace is greater than 40 minutes.

[0017] Furthermore, in step 1), the total time that the slab is in the furnace is greater than 185 minutes.

[0018] Furthermore, in step 1), the soaking period is greater than 30 minutes.

[0019] Furthermore, in step 2), the temperature of the rough rolling intermediate billet is controlled at 1090-1120°C.

[0020] Furthermore, in step 2), the thickness of the rough-rolled intermediate billet is controlled at 32 to 38 mm.

[0021] Furthermore, in step 4), the finishing rolling outlet temperature is controlled at 910-930°C.

[0022] Further, in step 6), from F1 to F4, ΔSG is 35 to 55 mm; from F5 to F7, ΔSG is 55 to 90 mm.

[0023] Compared with the existing method, the present invention has the following beneficial effects:

[0024] The present invention ensures the uniformity of the temperature of thin-gauge medium-high carbon slabs by optimizing the heating and steel burning system, improves the parameters of the load and rolling speed of each rough rolling pass, improves the plate shape of the rough rolling intermediate billet, increases the temperature of the thin-gauge medium-high carbon intermediate billet, reduces the allowance of the guide gauge of each stand of the finishing mill, reduces the probability of strip deviation during head threading, improves threading stability, and finally optimizes the load distribution of each stand of the finishing rolling tandem mill group and the coordinated use of the bending roll force, improves the straightness of the plate shape during rolling, systematically solves the instability problem of medium-high carbon rolling, and effectively solves the accidents of folding and steel jamming and tail swinging during medium-high carbon thin-gauge rolling, thereby improving the rolling stability of medium-high carbon thin-gauges, reducing and improving the quality of medium-high carbon products and the comprehensive yield rate.

[0025] By adopting the method of the present invention, the rolling stability of thin-gauge medium-high carbon steel is greatly improved, and the rolling success rate of thin-gauge medium-high carbon steel is increased from 58.13% to 95.35%; at the same time, the quality defects caused by production accidents are reduced, and the quality defect rate is reduced from 12.32% to 2.65%; the yield rate of thin-gauge medium-high carbon steel is increased from 94.36% to 98.32%. DETAILED DESCRIPTION

[0026] The present invention discloses a method for producing thin-gauge medium-high carbon steel. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0027] A method for producing thin-gauge medium-high carbon steel comprises the following steps:

[0028] 1. Control the slab charging temperature to 350℃~700℃, the slab preheating time in the heating furnace is greater than 40 minutes, the heating temperature in the preheating section is 700℃~850℃; the total slab in the furnace time is greater than 185 minutes, the soaking time is greater than 30 minutes, and the heating out of the furnace temperature is controlled at 1240℃~1260℃.

[0029] 2. Rough rolling is carried out by two rolling mills, the front and rear rolling mills are represented by R1 and R2 respectively, the rolling speed of each pass of R1 rolling mill is set to 1.8-2.2 m / s, 2.2-2.5 m / s, 2.3-2.6 m / s; the rolling speed of each pass of R2 rolling mill is set to 3.1-3.5 m / s, 4.0-4.5 m / s, 4.1-4.6 m / s. The temperature of the intermediate billet during rough rolling is controlled at 1090℃~1120℃.

[0030] 3. The thickness of raw slab is 170mm~230mm, the load distribution of R1 three passes is 20%~22%, 17%~22%, 13%~16% respectively; the load distribution of R2 three passes is 15%~18%, 13%~17%, 10%~13% respectively. The thickness of rough rolling intermediate slab is controlled at 32~38mm.

[0031] 4. The outlet temperature of finishing rolling is controlled at 910℃~930℃. Finishing rolling adopts seven rolling mills, which are represented by F1 to F7, and the load distribution is as follows: F1 is 30%~42%, F2 is 30%~41%, F3 is 10%~18%, F4 is 5%~10%, F5 is 2%~6%, F6 is 1.5%~5%, and F7 is 1.2%~1.8%.

[0032] 5. The plate shape between each rolling mill in finishing rolling is controlled to be straight or slightly double-sided. The plate shape of each stand is controlled by the bending roll force. The use range of the bending roll force of each stand F1-F7 is:

[0033] The bending roll force of F1 frame is 750KN~1000KN, the bending roll force of F2 frame is 700KN~950KN, the bending roll force of F3 frame is 600KN~900KN, the bending roll force of F4 frame is 500KN~800KN, the bending roll force of F5 frame is 440KN~750KN, the bending roll force of F6 frame is 400KN~700KN, and the bending roll force of F7 frame is 330KN~650KN.

[0034] 6. The guide opening of each stand of the finishing rolling mill is set to be △SG more than the strip width, as follows:

[0035] △SG n =35mm~55mm; △SG p =55mm~90mm;

[0036] Where △SG represents the guide gauge allowance value;

[0037] n represents racks 1-4, and p represents racks 5-7.

[0038] Embodiment 1:

[0039] A method for producing medium-high carbon No. 50 steel with a thickness of 1.8 mm and a width of 1250 mm, specifically comprising the following steps:

[0040] 1. The charging temperature of the slab is 450℃. The preheating time of the slab in the heating furnace is 45 minutes, and the heating temperature of the preheating section is 800℃. The total time of the slab in the furnace is 186 minutes, the soaking time is 35 minutes, and the heating out of the furnace temperature is controlled at 1245℃.

[0041] 2. The rough rolling mill adopts two rolling mills. The front and rear rolling mills are represented by R1 and R2 respectively. R1 and R2 have different rolling passes. The rolling speed of each pass of R1 is set to 2.0 m / s, 2.5 m / s, and 2.6 m / s respectively; the rolling speed of each pass of R2 rolling mill is set to 3.3 m / s, 4.3 m / s, and 4.5 m / s respectively. The temperature of the rough rolling intermediate billet is controlled at 1100℃; the finishing rolling outlet temperature is controlled at 920℃.

[0042] 3. The raw material is 230mm thick slab, and the load distribution of the three passes of R1 is 20%, 17%, and 14% respectively; the load distribution of the three passes of R2 mill is 16%, 15%, and 12% respectively, and the thickness of the rough rolling intermediate slab is controlled at 35mm. The load distribution of the seven finishing mills F1-F7 is: F1 is 30%, F2 is 36%, F3 is 16%, F4 is 7%, F5 is 6%, F6 is 3.5%, and F7 is 1.5%.

[0043] 4. The plate shape between each rolling mill in the finishing rolling is controlled to be straight or slightly double-sided, and the plate shape is controlled by the bending roll force. The bending roll force of the F1 stand is 900KN, the bending roll force of the F2 stand is 850KN, the bending roll force of the F3 stand is 830KN, the bending roll force of the F4 stand is 650KN, the bending roll force of the F5 stand is 600KN, the bending roll force of the F6 stand is 5500KN, and the bending roll force of the F7 stand is 5000KN.

[0044] 5. The guide gauge opening allowance values ​​of each rolling mill from F1 to F7 are:

[0045] △SG1=35mm; △SG2=35mm; △SG3=35mm; △SG4=35mm; △SG5=55mm; △SG6=55mm; △SG7=55mm;

[0046] The guide gauge widths of the rolling mills from F1 to F7 are 1285mm, 1285mm, 1285mm, 1285mm, 1305mm, 1305mm, and 1305mm respectively.

[0047] Embodiment 2:

[0048] A method for producing medium-high carbon 65Mn steel with a thickness of 2.0 mm and a width of 1200 mm, specifically comprising the following steps:

[0049] 1. The charging temperature of the slab is 550℃. The preheating time of the slab in the heating furnace is 50 minutes, and the heating temperature of the preheating section is 850℃. The total time of the slab in the furnace is 195 minutes, the soaking time is 40 minutes, and the heating out of the furnace temperature is controlled at 1250℃.

[0050] 2. The rough rolling mill adopts two rolling mills. The front and rear rolling mills are represented by R1 and R2 respectively. R1 and R2 have different rolling passes. The rolling speed of each pass of R1 is set to 2.2m / s, 2.5m / s and 2.6m / s respectively; the rolling speed of each pass of R2 is set to 3.5m / s, 4.5m / s and 4.6m / s respectively. The temperature of the rough rolling intermediate billet is controlled at 1120℃; the finishing outlet temperature is controlled at 930℃.

[0051] 3. The raw material is 170mm thick slab. The three passes of the rough rolling mill R1 are distributed with 20%, 22% and 16% respectively; the three passes of the R2 rolling mill are distributed with 15%, 17% and 13% respectively. The thickness of the rough rolling intermediate slab is controlled at 38mm. The load distribution of the seven finishing rolling mills F1-F7 is: F1 is 33%, F2 is 35%, F3 is 16%, F4 is 6%, F5 is 5.4%, F6 is 3%, and F7 is 1.6%.

[0052] 4. The plate shape of each rolling mill in the finishing rolling mill is controlled to be straight or slightly double-sided. The plate shape of each frame is controlled by the bending roll force. The use range of the bending roll force of each frame F1-F7 is: the bending roll force of the F1 frame is 900KN, the bending roll force of the F2 frame is 880KN, the bending roll force of the F3 frame is 800KN, the bending roll force of the F4 frame is 750KN, the bending roll force of the F5 frame is 6800KN, the bending roll force of the F6 frame is 6500KN, and the bending roll force of the F7 frame is 600KN.

[0053] 5. The guide gauge opening allowance values ​​of each rolling mill from F1 to F7 are:

[0054] △SG1=40mm; △SG2=40mm; △SG3=40mm; △SG4=40mm; △SG5=60mm; △SG6=60mm; △SG7=60mm;

[0055] The guide gauge widths of the rolling mills from F1 to F7 are 1240mm, 1240mm, 1240mm, 1240mm, 1260mm, 1260mm, and 1260mm respectively.

[0056] The present invention can improve the rolling stability of medium-high carbon thin gauge steel, reduce the accidents of folding and jamming steel and tail swinging during the rolling of medium-high carbon thin gauge steel, and improve the quality and comprehensive yield rate of medium-high carbon products. By adopting the method of the present invention, the rolling stability of thin gauge medium-high carbon steel is greatly improved, and the success rate of rolling thin gauge medium-high carbon steel is increased from 58.13% to 95.35%; at the same time, the quality defects caused by production accidents are reduced, and the quality defect rate is reduced from 12.32% to 2.65%; the yield rate of thin gauge medium-high carbon steel is increased from 94.36% to 98.32%.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for producing thin-gauge medium-high carbon steel, characterized in that: The thin gauge refers to a hot-rolled strip steel with a thickness of 1.5 to 3.5 mm, and the medium-high carbon steel refers to a carbon steel with a carbon mass content of 0.25% to 0.6%, which specifically includes the following steps: 1) The slab charging temperature is controlled at 350-700℃, the heating temperature in the preheating section is controlled at 700-850℃; the heating out of the furnace temperature is controlled at 1240-1260℃; 2) Rough rolling is carried out by two or more rolling mills, the first rolling mill is R1, the second rolling mill is R2, the first rolling speed of R1 is 1.8-2.2 m / s, the second rolling speed is 2.2-2.5 m / s, and the third rolling speed is 2.3-2.6 m / s; R2 The first rolling speed is 3.1-3.5 m / s, the second rolling speed is 4.0-4.5 m / s, and the third rolling speed is 4.1-4.6 m / s; 3) R1 The first pass load is 20% to 22%, the second pass load is 17% to 22%, and the third pass load is 13% to 16%; 4) Finish rolling is carried out by more than seven rolling mills, the first rolling mill is F1, the second rolling mill is F2, the third rolling mill is F3, the fourth rolling mill is F4, the fifth rolling mill is F5, the sixth rolling mill is F6, and the seventh rolling mill is F7; Load distribution: F1 is 30% to 42%, F2 is 30% to 41%, F3 is 10% to 18%, F4 is 5% to 10%, F5 is 2% to 6%, F6 is 1.5% to 5%, F7 is 1.2% to 1.8%; 5) Control the plate shape by bending roller force, control the F1 bending roller force to 750-1000KN, the F2 bending roller force to 700-950KN, the F3 bending roller force to 600-900KN, the F4 bending roller force to 500-800KN, the F5 bending roller force to 440-750KN, the F6 bending roller force to 400-700KN, and the F7 bending roller force to 330-650KN; 6) Set the guide opening of each stand of the finishing rolling mill to K, mm; the strip width to D, mm; Then △SG=KD, △SG is the guide ruler allowance value, mm.

2. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 1), the thickness of the raw material slab is 170 to 230 mm.

3. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 1), the preheating time of the heating furnace is greater than 40 minutes.

4. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 1), the total time the slab is in the furnace is greater than 185 minutes.

5. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 1), the soaking period is greater than 30 minutes.

6. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 2), the temperature of the rough rolling intermediate billet is controlled at 1090-1120°C.

7. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 2), the thickness of the rough rolling intermediate billet is controlled at 32 to 38 mm.

8. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 4), the finishing outlet temperature is controlled at 910-930°C.

9. The method for producing thin-gauge medium-high carbon steel according to claim 1, characterized in that: In step 6), from F1 to F4, ΔSG is 35 to 55 mm; from F5 to F7, ΔSG is 55 to 90 mm.