CN102688889A - Intermediate roll form of cold continuous mill - Google Patents

Abstract

The invention relates to the field of continuous cold rolling, in particular to a roll shape of a continuous cold rolling mill. A kind of roll shape of the middle roll of a cold tandem rolling mill, the roll shape of the upper and lower rolls is anti-symmetrically arranged, the axis of the middle roll is the x-axis, the radial direction of the middle roll is the y-axis, and the apex of the head of the middle roll is the origin, said middle roll shape for

. The roll shape of the middle roll of the cold tandem rolling mill of the present invention is a combination of a cubic polynomial and a sine function, which can enhance the shape control ability of the rolling mill to the narrow strip steel, improve the shape quality of the finished strip steel, and perform circular arc repair on the end roll shape at the same time. shape, reduce the contact pressure peak between the rolls, improve the uniformity of the contact pressure distribution between the rolls, and prolong the service life of the rolls.

Description

Intermediate roll shape of cold tandem rolling mill

technical field

The invention relates to the field of continuous cold rolling, in particular to a roll shape of a continuous cold rolling mill.

Background technique

The automotive and construction industries require large quantities of cold-rolled strips. In consideration of weight reduction, energy saving and cost reduction, it is required to use thinner steel plates, which puts forward higher requirements on the mechanical properties of strip steel. In order to ensure safety in use, high-strength steel is currently developing in the direction of thin gauge and high strength, and the problem of plate shape has become more and more prominent.

Due to the high yield limit of high-strength steel, it means that each stand must have a relatively large rolling force during continuous cold rolling, which will inevitably cause serious deflection of the roll system and large roll gap convexity, resulting in high-strength steel Wave-shaped defects are prone to occur during rolling. For the six-high CVC (Continuously Variable Crown: Continuously Variable Crown) cold tandem mill, the method to control the edge wave defect of high-strength steel is to increase the positive displacement of the CVC intermediate roll and increase the positive bending force of the work roll and the intermediate roll. When the existing tandem cold rolling mill is producing narrow material high-strength steel, the roll shifting amount of the middle roll of the fifth stand of the rolling mill has basically reached the positive limit, and the bending force of the work roll and the middle roll has also reached a large value. However, even in this way, the edge wave defect of about 800mm narrow high-strength steel cannot be effectively eliminated.

The existing tandem cold rolling mill is a six-high five-stand acid-rolling combined unit, which adopts the intermediate roll CVC technology, and the roll profile curve of the intermediate roll is a cubic CVC roll profile. When the steel width changes from the maximum to the minimum, the crown control ability of the CVC intermediate roll drops very sharply. That is to say, the crown control ability of the rolling mill drops to a low level when producing narrow material, which is not difficult to understand the edge wave defect that occurs when producing narrow material high-strength steel.

Contents of the invention

The technical problem to be solved by the present invention is to provide an intermediate roll shape of a cold tandem mill (named HVC roll shape), which is a combination of a cubic polynomial and a sine function, which can enhance the shape control ability of the rolling mill for narrow strip steel. The shape quality of the finished strip is improved.

The present invention is achieved in the following way: a roll shape of the middle roll of a cold tandem rolling mill, the roll shape of the upper and lower rolls is anti-symmetrically arranged, the axis of the middle roll is the x axis, the radial direction of the middle roll is the y axis, and the head of the middle roll The vertex is the origin,

为 The middle roll roll shape

for

         (1)

(1)

In formula (1): α is a constant with a range of 360 to 450

L is the length of the middle roll body (mm)

    x is the coordinates of the axis body, and the value range is 0~L

R ₀ is the radius of the middle roller (mm)

is a polynomial coefficient, calculated by formulas (3), (4), (5), and (6)

                                (3)

(3)

        (4)

(4)

(5)

          (6)

(6)

In formula (3), (4), (5), (6):

B: Width of strip steel normally rolled by rolling mill (mm)

：中间辊窜辊最大行程（mm）

: Maximum stroke of intermediate roll shifting (mm)

：中间辊负窜至极限位置时对应的空载辊缝二次凸度（mm）

: The secondary crown of the unloaded roll gap corresponding to the intermediate roll shifting to the limit position (mm)

: The secondary convexity of the unloaded roll gap when the intermediate roll is moving to the limit position (mm)

：中间辊窜至极限位置时对应的空载辊缝四次凸度（mm）。

: Corresponding quaternary convexity of the unloaded roll gap when the intermediate roll moves to the limit position (mm).

为 The roller-shaped tail is superimposed with a section of arc curve modification section, and the function equation of the arc curve modification section is

for

                 

                 

In the formula: R is the arc radius of the modification curve, and the value is 8E04~4E05; the length of the modification section of the arc curve is 70~150mm.

The roll shape of the intermediate roll of the cold tandem rolling mill of the present invention is a combination of a cubic polynomial and a sine function, which expands the adjustment range of the secondary crown of the rolling mill and enhances the rolling mill’s ability to control the shape of the narrow strip; a section of arc curve is superimposed on the tail of the roll shape After the trimming section, it can also improve the edge contact stress concentration between the intermediate roll and the backup roll, between the intermediate roll and the working roll caused by the upturning of the edge, reduce the contact pressure peak between the rolls, and improve the uniformity of the contact pressure distribution between the rolls. Thereby reducing roll wear, avoiding roll spalling and prolonging service life.

The invention greatly improves the flatness control ability of the rolling mill on the high-strength steel narrow material, and finally realizes the improvement of the flatness quality of the finished strip steel.

Description of drawings

Fig. 1 is the profile schematic diagram of intermediate roll of tandem cold rolling mill of the present invention;

Figure 2a is a distribution diagram of the contact pressure between the intermediate roll and the backup roll;

Figure 2b is a distribution diagram of the contact pressure between the work roll and the intermediate roll;

Fig. 3 is a graph showing the relationship between the secondary crown control ability of the roll profile and the original roll profile as a function of the strip width in the present invention.

； Among Fig. 2: ━ roll shape of the present invention,

;

Among Fig. 3: the solid point is the original roll shape, and the hollow point is the roll shape of the present invention.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

和下辊辊形

为 As shown in Figure 1, the roll shape of the middle roll of a cold tandem rolling mill, the roll shape of the upper and lower rolls is anti-symmetrically arranged, the axis of the middle roll is the x-axis, the radial direction of the middle roll is the y-axis, and the top of the head of the middle roll is As the origin, in this embodiment, the upper roll is the reference roll shape, the lower roll and the upper roll are arranged anti-symmetrically, and the axial distance between the upper and lower rolls is D+H. The upper roll shape

and lower roll shape

for

        (1)

(1)

                                      (2)

(2)

In formula (1), (2): α is a constant, the value is 360

         L is the length of the middle roll body, 1970mm

R ₀ is the radius of the middle roller (mm)

为多项式系数，由公式(3)、(4)、(5)、(6)算出

is a polynomial coefficient, calculated by formulas (3), (4), (5), and (6)

                                        (3)

(3)

                  (4)

(4)

                                      (5)

(5)

                    (6)

(6)

In formula (3), (4), (5), (6):

B: The width of the strip steel normally rolled by the rolling mill is 1185mm

: The maximum stroke of intermediate roll shifting is 120mm

：中间辊负窜至极限位置时对应的空载辊缝二次凸度0mm

: The secondary convexity of the unloaded roll gap is 0mm when the intermediate roll moves to the limit position.

: Secondary convexity of the unloaded roll gap when the intermediate roll is moving to the limit position -0.7mm

：中间辊窜至极限位置时对应的空载辊缝四次凸度-0.1mm~0.1mm

: When the intermediate roll moves to the limit position, the corresponding four-time convexity of the unloaded roll gap -0.1mm~0.1mm

As shown in Figure 1, this embodiment can be further described as, when the axial movement distance of the roll is s, the roll gap function Expressed as:

                                      (7)

(7)

In formula (7): D+H is the axial distance between the upper and lower rollers

s is the roll shifting stroke of the middle roll -120mm~+120mm

Furthermore, the secondary convexity and quaternary convexity of the roll gap formed by the entire length of the roll can be obtained.

为

，式中：R为修形曲线圆弧半径，取值1.5E05；圆弧曲线修形段长度为100mm。 In order to improve the edge contact stress concentration between the intermediate roll and the back-up roll, between the intermediate roll and the working roll caused by the upturning of the roll-shaped edge of the intermediate roll of the present invention, a section of arc curve modification section is superimposed on the roll-shaped tail. Functional Equation of Circular Curve Modification Section

for

, where: R is the arc radius of the modification curve, the value is 1.5E05; the length of the modification segment of the arc curve is 100mm.

Use finite element software to simulate and calculate the roll shape of the present invention, and compare the contact pressure distribution between the intermediate roll and the backup roll of the original roll shape, the contact pressure distribution between the intermediate roll and the working roll, and the roll of the present invention under no-load state. The ability to control the crown of the profile and the original roll profile at different strip widths.

Define the crown control capability as the amount of change in the crown of the unloaded roll gap when the strip width is B and the intermediate roll moves from the negative limit position to the positive limit position.

The distribution of contact pressure between rollers includes two items: the uniformity of contact pressure distribution between rollers and the peak value of contact pressure between rollers. The former affects the uneven wear of the roll axis, and the latter affects the peeling of the roll. From the simulation results in Fig. 2a and b, it can be seen that the roll shape of the intermediate roll of the present invention can reduce the contact pressure peak between the rolls to a certain extent, improve the uniformity of the contact pressure distribution between the rolls, thereby reducing roll wear, avoiding roll peeling, and prolonging the service life.

和

，如公式（8）和（9）所示， For the strip steel whose width is B, the secondary convexity of the roll gap of the roll shape of the present invention at the limit position of roll shifting is respectively

and

, as shown in equations (8) and (9),

        (8)

(8)

        (9)

(9)

如公式（10）所示， The control ability of the roll shape of the present invention can be controlled by the secondary convexity of the roll gap at the extreme position of the two shifting rolls. and the difference

As shown in formula (10),

(10)

，如公式（11）所示， For strip steel with a width of B, the control ability of the secondary variable crown of the original roll shape

, as shown in Equation (11),

(11)

Substituting each width data into formula (10) and formula (11) respectively calculates the crown control ability of the roll shape of the present invention and the original roll shape shown in Table 1,

Table 1

As can be seen from Table 1 and Fig. 3, when the strip width dropped from 1600mm to 700mm, the ability to change the strip crown of the original roll shape decreased by 80.86%, while the roll shape of the present invention only decreased by 52.29%, while in While improving the convexity control ability of narrow materials, the convexity control ability of wide materials is also slightly improved.

Claims (2)

1. cold continuous rolling intermediate calender rolls roll forming, the roll forming antisymmetry of upper and lower roll is provided with, it is characterized in that: the axis with intermediate calender rolls is the x axle, intermediate calender rolls radially be the y axle, intermediate calender rolls head summit is an initial point,

Described intermediate calender rolls roll forming

does

(1)

In the formula (1): α is a constant, span 360～450

L is intermediate calender rolls barrel length (mm)

X is the axle body coordinate, span 0 ~ L

R ₀Be intermediate calender rolls radius (mm)

is multinomial coefficient, calculated by formula (3), (4), (5), (6)

(3)

(4)

(5)

(6)

In formula (3), (4), (5), (6):

B: milling train often rolls strip width (mm)

: intermediate roll shifting stroke (mm)

: intermediate calender rolls is born unloaded roll gap secondary convexity (mm) corresponding when scurrying to extreme position

: the unloaded roll gap secondary convexity (mm) of correspondence when intermediate calender rolls is just being scurried to extreme position

: four convexitys of unloaded roll gap (mm) of correspondence when intermediate calender rolls is scurried to extreme position.

2. cold continuous rolling intermediate calender rolls roll forming as claimed in claim 1; It is characterized in that: this roll forming afterbody is superimposed with one section circular curve correction of the flank shape section, and described circular curve correction of the flank shape section functional equation does

In the formula: R is the modification curve arc radius, value 8E04～4E05; Circular curve correction of the flank shape segment length is 70～150mm.

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