CN112264465B

CN112264465B - Centrifugal composite roller

Info

Publication number: CN112264465B
Application number: CN202011048672.1A
Authority: CN
Inventors: 陈刚; 王武洲; 杜旭景; 魏元超
Original assignee: Wuhan Iron and Steel Co Ltd
Current assignee: Wuhan Iron and Steel Co Ltd
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2022-06-17
Anticipated expiration: 2040-09-29
Also published as: CN112264465A

Abstract

The invention discloses a centrifugal composite roller which comprises a roller body, wherein the thickness of a supporting layer of the roller body is more than 5mm and less than or equal to 20mm, and the hardness of a roller shoulder part of the roller body is more than HSD 60. The invention has the beneficial effects that: by changing the size of the roller shoulder, the material of the roller shoulder is further changed, the hardness and the wear resistance are improved, and the retention capability of the roundness precision in the service life cycle of the roller is ensured; not only can reduce the accidental consumption caused by the grinding roundness precision, but also can improve the rolling stability and the plate type precision of the strip steel.

Description

Centrifugal composite roller

Technical Field

The invention relates to the field of hot continuous rolling mills, in particular to a centrifugal composite roller.

Background

The working roll of the hot continuous rolling mill is generally a centrifugal composite roll, namely, the outer layer is made of high-alloy and high-hardness wear-resistant material and is compounded with low-alloy and high-toughness nodular cast iron material, and a bonding area, namely a material fusion transition area, exists between the two materials.

As shown in FIG. 5, due to the structural limitation of the rolling mill, the roll body part of the hot continuous rolling working roll has only limited thickness from the new roll diameter D0 to be used, namely a working layer, and the roll is scrapped and can not be used any more after the working layer at the part is used to the scrapped diameter D1. In order to ensure that the roller is used to the scrapped diameter, a certain supporting layer H is still needed to ensure safe use, the thickness of the supporting layer is generally 5mm, and when the diameter D3 of the roller shoulder part is smaller (D1-D3)/2 is larger than 5mm, the supporting layer added by the conventional working layer can not ensure that the roller shoulder is made of an outer layer material.

When most of centrifugal composite rolls are designed, due to size reasons, after machining, roll shoulder parts of the rolls are made of roll core parts or bonding layer transition materials with low hardness, and the centrifugal composite rolls belong to bonding in a semi-solidification state, and the bonding layer transition materials are mixed materials, so that the components are uneven and the hardness is not even. No matter be core material or transition material, its wearability is relatively poor and lead to wearing and tearing inhomogeneous, and in the long-term use, there is corruption and wearing and tearing in roll shoulder position, leads to the roller shoulder precision in the middle and later stage to appear the degradation, influences roll body circularity precision, and this kind of phenomenon is upgrading continuously at the material and is regenerating, life cycle prolongs the back by a wide margin, and the degree is more serious.

When the roundness of the roll body of the roll exceeds a certain value, the roll gap changes along with the roundness of the roll, the roll gap adjusting frequency of a rolling mill AGC is accelerated, and meanwhile, the loop shakes, the result of which is the change of the rolling force is shown as the loop shaking, fig. 1 is a rolling force fluctuation curve in electrical data IBA, the rolling force fluctuation curve obviously corresponds to the roundness of the roll in fig. 2, a large strip steel plate shape fluctuation graph 3 is shown, a product thickness fluctuation graph 4 cannot meet the requirements of the next process or a user, quality objections or waste products are caused, severe persons cause unstable rolling, steel scrap is easy to occur, equipment faults and long-time shutdown are caused.

CN201410748759.8 method for repairing roundness out-of-tolerance of shoulder ring of finish rolling working roll introduces a method for repairing roundness out-of-tolerance of shoulder ring of finish rolling working roll, i.e. firstly, a standard roll is adopted to adjust roundness and levelness of two grinding machine supporting shoes, and the two grinding machine supporting shoes form a positioning surface; hanging a finish rolling working roll with out-of-roundness of the roll shoulder rings at a machining position of a grinding machine, wherein the roll shoulder rings at two ends are positioned on a positioning surface; grinding and polishing the roll shoulder rings at the two ends of the finish rolling working roll by a grinding machine, wherein the grinding and polishing process comprises coarse grinding, middle grinding and fine grinding; the roundness of the roller shoulder rings at the two ends of the finish rolling working roller is detected to be less than or equal to 0.01mm, the grinding of the roller shoulder rings at the two ends of the finish rolling working roller is finished, and the grinding machine is hung away from the grinding machine.

The control of the ovality of the finish rolling working roll of the hot rolling production line, Gansu metallurgy, No. 3 to No. 29 to 31 in 2018 introduces the problem that the ovality precision of the finish rolling working roll of the plum steel hot rolling production line is poor in use, so that part of the rolls cannot be normally put into use and can be only placed for a long time, and the normal turnover of the rolls is influenced.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a centrifugal composite roller to overcome the defects in the prior art.

In order to solve the technical problem, the invention provides a centrifugal composite roller which comprises a roller body, wherein the thickness of a supporting layer of the roller body is more than 5mm and less than or equal to 20mm, and the hardness of a roller shoulder part of the roller body is more than HSD 60.

As an improvement of the technical scheme, the roller shoulder part adopts a high-alloy and high-hardness wear-resistant high-speed steel outer layer material of the roller.

As an improvement of the technical scheme, compared with the core material of the roller body and the transition material of the binding layer, the material of the roller shoulder part has alloy with the total amount higher than 6 percent.

As an improvement of the technical proposal, the alloy content of the core material of the roller body is less than or equal to 1 percent.

As an improvement of the technical proposal, the elements of the alloy at least comprise Cr, Mo, Ni, Mn, V and W, wherein Cr is more than or equal to 4 percent, Mo is more than or equal to 2 percent, Ni is more than or equal to 0.4 percent, Mn is more than or equal to 0.4 percent, and V and W are trace.

As an improvement of the technical proposal, the alloy ensures that the matrix structure strength of the material is more than HV450 and the content of formed carbide is more than or equal to 5 percent.

As an improvement of the technical scheme, the diameter of a working layer of the roller body is 825mm, and the thickness of the working layer is 70 mm-80 mm; the diameter of the roller shoulder is 720mm, and the diameter of the supporting layer is 735 mm.

Compared with the prior art, the invention has the beneficial effects that:

by changing the size of the roller shoulder, the material of the roller shoulder is further changed, the hardness and the wear resistance are improved, and the retention capability of the roundness precision in the service life cycle of the roller is ensured; not only can reduce the accidental consumption caused by the grinding roundness precision, but also can improve the rolling stability and the plate type precision of the strip steel.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the contents of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following detailed description is given in conjunction with the preferred embodiments.

Drawings

FIG. 1 is a rolling force jitter curve when roundness is out of tolerance;

FIG. 2 is a measuring curve of the out-of-tolerance of the roundness of the roll;

FIG. 3 is a diagram showing the fluctuation of the shape of the steel strip when the roundness is out of tolerance;

FIG. 4 shows the fluctuation of the strip thickness when the roundness is out of tolerance;

FIG. 5 is a schematic roll size diagram;

FIG. 6 is the metallographic structure of the original roll shoulder;

FIG. 7 shows the metallographic structure of the shoulder of the roll according to the invention;

FIG. 8 is the original roll shoulder dimensions;

figure 9 shows the shoulder size of the rolls of the present invention.

Detailed Description

Other aspects, features and advantages of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.

On the premise of not influencing the use and grinding of the roller, the size design of the roller shoulder 130 of the roller body 1 is properly increased, so that the diameter range of the roller shoulder 130 after redesign is contained in the material of the working layer 110 as far as possible, and the casting difficulty caused by simply increasing the thickness of the working layer 110 is reduced.

The technical scheme adopted by the invention determines that the optimal design principle of the supporting layer 120 is more than 5mm and less than or equal to 20mm, and the technical scheme can meet the manufacturability requirement and the use safety requirement of centrifugal compounding and can meet the grinding requirements of different design sizes of the roller shoulder 130. If the thickness requirement of the technical scheme is exceeded by the supporting layer 120, on one hand, the amount of poured molten iron is increased more when the outer layer is centrifugally cast, so that the load of a centrifugal machine is increased, and meanwhile, the cooling speed is low when the outer layer is solidified, so that the tissue density of the roller is reduced; when the thickness of the support layer 120 is designed to exceed 20mm, the cross-sectional area of the core portion is reduced, and the toughness of the roll is weakened during use, so that roll breakage is likely to occur.

The further improvement of the technical scheme is that the diameter and the use thickness of the hot continuous rolling working roll are considered to be different, the selection of the supporting layer 120 meets the requirement that 2H/(D0-D1) is less than or equal to 40 percent, and the design is carried out by taking the roll shoulder 130 as an outer layer as far as possible under the condition, namely H is more than or equal to (D1-D3)/2).

As shown in figures 6 and 7, the technical scheme is further improved in that the roll shoulder 130 is made of high-alloy high-hardness wear-resistant high-speed steel outer layer material of the roll by designing according to H ≧ (D1-D3)/2), the material has an alloy with the total amount of not less than 6% compared with a core material and a bonding layer transition material, wherein Cr is not less than 4%, Mo is not less than 2%, Ni is not less than 0.4%, Mn is not less than 0.4%, V is trace and W is trace, the content of the alloy in the core material is low and is not more than 1%, the alloy enables the matrix structure strength of the material to be generally greater than HV450, the content of formed carbides is not less than 5%, and the material has strong wear resistance, corrosion resistance and oxidation resistance. The technical scheme can ensure that the material of the roller shoulder 130 part is the outer layer material, the hardness can reach more than HSD60, and the performance requirement of the roller shoulder 130 is ensured.

As shown in the figures 5, 8 and 9, according to the metal thickness range of the working layer 110, the original size 675mm of the roller shoulder 130 is redesigned to be 720mm, the single side difference between the size of the roller shoulder 130 and the scrapped size 735mm is 7.5mm, and the size of the roller shoulder 130 is ensured to be the working layer.

When an original roller is ground, a low tile with the height of 177mm is selected, the thickness of the bearing shoe alloy layer is 30mm, the adjusting capacity of the bearing shoe screw rod is 40mm, and in order to select a better working range, the adjusting range is usually controlled to be 30 mm. After the size of the roller shoulder 130 is redesigned, according to the abrasion of the bearing shoe and the adjusting range of the screw rod, a bottom shoe with the height of 162mm can be selected during grinding, and other operation modes are unchanged: the purpose of tile adjustment is to ensure that the roller is horizontal, namely the conicity in the vertical direction and the horizontal direction meets the requirements of starting and running of a grinding machine; the height of the roller in the vertical direction is adjusted by the height of the bottom tile, and the position of the roller in the horizontal direction is adjusted by the side tile. In the process of adjusting the tiles in the middle, the height value of each tile must be in the numerical range of-350 to +350 mu m.

The material design and casting process variation of the roll shoulder 130 will be described.

The diameter of the new roller of the roller is 825mm, the scrapped diameter is 735mm, the thickness of the used layer is 45mm, the thickness of the outer layer of the conventional design supporting layer 1205mm design is 50mm, the size of the original roller shoulder 130 is 675mm, the roller shoulder 130 cannot be guaranteed to be made of the outer layer material and be located at the position of the core part, and the hardness is lower and is about HSD 40.

After the size of the roller shoulder 130 is adjusted, the thickness of the supporting layer 120 of the working layer 110 is designed to be 7.5mm, the position of the roller shoulder 130 is ensured to be made of an outer layer material, and the detection hardness is more than HSD 70.

The alloy content of the roll shoulder 130 part is improved to more than 6 percent from the original <1 percent, the hardness is improved to more than HSD60 from HSD40, and the problems of abrasion, corrosion and poor roundness are not generated when the roll shoulder 130 part is used.

While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. The centrifugal composite roller is characterized by comprising a roller body, wherein the thickness of a supporting layer of the roller body is more than 5mm and less than or equal to 20 mm; the hardness of the roll shoulder part of the roll body is more than HSD 60; the roller shoulder part adopts a high-alloy high-hardness wear-resistant high-speed steel outer layer material of the roller; the material of the roll shoulder has a total of more than 6% alloy compared to the roll body core material and the bonding layer transition material; the elements of the alloy at least comprise Cr, Mo, Ni, Mn, V and W, wherein Cr is more than or equal to 4 percent, Mo is more than or equal to 2 percent, Ni is more than or equal to 0.4 percent, Mn is more than or equal to 0.4 percent, and V and W are trace; the diameter of the working layer of the roller body is 825mm, and the thickness of the working layer is 70 mm-80 mm; the diameter of the roller shoulder is 720mm, and the diameter of the supporting layer is 735 mm.

2. A centrifugal composite roll as claimed in claim 1, wherein the alloy content of the core material of the roll body is 1% or less.

3. A centrifugal composite roll as claimed in claim 1, wherein the alloy is such that the matrix structure strength of the material is greater than HV450 and the carbide formation content is 5% or more.