阅读说明：本技术 连铸大方坯连续曲率凸形辊制造方法 (Method for manufacturing continuous-casting bloom continuous-curvature convex roller ) 是由 徐荣军 刘俊江 万根节 李成斌 柳向椿 孟庆玉 于 2018-08-31 设计创作，主要内容包括：一种连铸大方坯连续曲率凸形辊制造方法,属金属铸造领域。其连续曲率凸形辊辊身工作部分的外轮廓曲线,由第一直线段AB、第一过渡曲线段BC、中间直线段CD、第二过渡曲线段DE和第二直线段EF构成；其第一过渡曲线段BC和第一直线段AB、中间直线段CD的一阶导数连续变化、二阶导数连续变化、曲率连续变化,构成一个具有连续变化曲率的第一过渡曲线；所述的第一过渡曲线BC与第二过渡曲线DE镜像对称。按照技术方案制造的连续曲率凸形辊,可使变形区域铸坯均匀变形,减少裂纹发生；凸形辊的过渡曲线可缩短,能进一步降低轧制压力和减少拉坯阻力。可广泛用于金属铸造领域。(A method for manufacturing a continuous curvature convex roller of a continuous casting bloom belongs to the field of metal casting. The outer contour curve of the roll body working part of the continuous curvature convex roll consists of a first straight line section AB, a first transition curve section BC, a middle straight line section CD, a second transition curve section DE and a second straight line section EF; the first transition curve segment BC, the first straight line segment AB, the first derivative continuous change, the second derivative continuous change and the curvature continuous change of the middle straight line segment CD form a first transition curve with continuously changing curvature; the first transition curve BC and the second transition curve DE are mirror symmetric. The continuous curvature convex roller manufactured according to the technical scheme can enable a casting blank in a deformation area to be uniformly deformed, and reduce the occurrence of cracks; the transition curve of the convex roller can be shortened, and the rolling pressure and the withdrawal resistance can be further reduced. Can be widely used in the field of metal casting.)

1. A method for manufacturing a continuous-casting bloom continuous-curvature convex roller is characterized by comprising the following steps:

the outer contour curve of the working part of the roll body of the continuous curvature convex roll consists of a first straight line section AB, a first transition curve section BC, a middle straight line section CD, a second transition curve section DE and a second straight line section EF;

the first transition curve segment BC, the first straight line segment AB, the first derivative continuous change, the second derivative continuous change and the curvature continuous change of the middle straight line segment CD form a first transition curve with continuously changing curvature;

similarly, the second transition curve section DE, the middle straight line section CD, the first derivative continuous change, the second derivative continuous change and the curvature continuous change of the second straight line section EF form a second transition curve with continuously changing curvature;

the first transition curve BC and the second transition curve DE are in mirror symmetry;

when the convex roller is manufactured and processed, firstly, a blank is cast according to the shape and the size requirements of the convex roller, and the working part of the roller body is processed according to the shape of the outer contour curve and along the central axis O₁O₂Rotating to obtain the continuous curvature convex roller;

for the existing flat roller, a lug boss can be firstly welded on the working part of the roller body, and the working part of the roller body is machined according to the shape of the outer contour curve and along the central axis O₁O₂Rotating to obtain a continuous curvature convex roller;

the convex roller manufactured by the method for manufacturing the continuous casting bloom continuous curvature convex roller can enable a casting blank in a deformation area to be uniformly deformed and reduce cracks;

the convex roller manufactured by the manufacturing method of the continuous-casting bloom continuous-curvature convex roller has the advantages that the transition curve can be shortened, the rolling pressure can be further reduced, and the withdrawal resistance can be further reduced.

2. The method for manufacturing a continuous curvature convex roll of a continuous casting bloom as set forth in claim 1, wherein the transition curve having a continuously varying curvature is formed by:

establishing a coordinate system, wherein the origin of coordinates is at a middle point O, the two points O, B meet the requirement of continuous second-order derivatives, and the point A meets the requirement of continuous first-order derivatives;

the curve equation of the boss of the convex roller is a curve which is axisymmetric along the central point A, the curve section OA is a curve on the left half side, and the curve section AB is a curve on the right half side;

the curve section OA is used as a left half curve of the boss, namely the first transition curve; the curve section AB is used as a right half curve of the boss, namely the second transition curve; the middle parts are connected by a horizontal straight line.

3. The method for manufacturing a continuous curvature convex roll of a continuous casting bloom as set forth in claim 1 or 2, wherein the curve equation of the first transition curve BC is expressed as follows:

the limiting conditions are as follows:

and point O: x is 0:

y＝0； (1)

and (B) point A: x is L/2:

y＝H； (4)

and B, point: x is L:

y＝0； (6)

i.e. a total of 8 constraints;

assuming that the transition curve of the boss is in a polynomial form, because of 8 constraints, the following should be:

y＝a₇x⁷+a₆x⁶+a₅x⁵+a₄x⁴+a₃x³+a₂x²+a₁x+a₀(9)

(1) the formula (8) represents, in place of the formulae (9), (10) and (11): solving an 8-element linear equation simultaneously to obtain:

a₀＝0；a₁＝0；a₂＝0；

since the 0, 1 and 2 derivatives of the curve are continuous, the curvature of the curve is continuous and belongs to a smooth curve.

4. The method for manufacturing a continuous-curvature male roll of a continuous-casting bloom as set forth in claim 1, wherein said second transition curve DE is formed by mirroring a midpoint of the first transition curve BC along the intermediate straight line segment CD as a center line.

Technical Field

The invention belongs to the field of metal casting, and particularly relates to a manufacturing method of a device for carrying out post-treatment or post-processing on a cast blank on site.

Background

The application publication No. CN 107377919A, the application publication No. 2017.11.24 of the Chinese patent application, discloses a method for improving the center density of a bearing steel casting blank, and discloses a convex roller, wherein the middle part of the convex roller is provided with a bulge 1, and the bulge 1 and two ends of the convex roller are in transition by a gradual curvature curve.

The application publication No. CN 106001475A, the application publication No. 2016.10.12 of the Chinese invention patent application, discloses a convex roller with gradually changed curvature for a continuous casting alloy steel bloom and a heavy pressing process, which designs a roller into a convex roller structure with gradually changed curvature; the convex roller has a boss height capable of compensating for the volume shrinkage in the height direction and a boss width capable of covering the most severely loosened and segregated region in the width direction. The arc of the arc changing area is controlled to have a curvature radius r not larger than 30 mm.

Chinese patent application publication No. CN 105983668A, published as 2016.10.05, discloses a "light weight roll, a light rolling device having the same, and a method for manufacturing a cast slab", wherein "the diameter of an end portion of the light weight roll is smaller than the diameter of an intermediate portion", and when a cross section including a rotation axis of the light weight roll is observed, an outer periphery between the intermediate portion and the end portion has a 1 st arc bulging toward the rotation axis on the end portion side, and a 2 nd arc bulging in a direction opposite to the bulging direction of the 1 st arc on the intermediate portion side, and an angle formed by a tangent line to both the 1 st arc and the 2 nd arc and the rotation axis is 40 ° or less. "

Although the smoothness of the profile curve of the boss is considered, the light-pressure lower convex roller in the technical scheme is continuous only under the condition of the first derivative (namely the curve is tangent to the curve and the curve is tangent to the straight line), and the tangent points are still singular points, namely stress concentration points, for example, the intersection of the arc curve and the arc curve only meets 0-order continuity, and the light-pressure lower convex roller is not a smooth curve in the true sense. The casting blank still receives stress inevitably in the rolling deformation process, and because the surface temperature of the casting blank is low and is usually at 700-.

When two circular arc curves are simultaneously used as the transition curve, the projection length AB of the transition curve on the x axis must be more than or equal to the boss height H, namely the sum of the minimum radii (R) of the two circular arcs₁+R₂) The height H of the boss is required to be more than or equal to the height H of the boss, otherwise, the two circular arcs cannot be connected.

Because the total length of the roller body is fixed, the length of a straight line segment DE at the center of the boss is determined by the width of an unsolidified liquid core at the center of a casting blank. An excessively long transition curve means that the straight line segments AB and EF at the ends of the projection become shorter, which is disadvantageous both in reducing rolling pressure and reducing withdrawal resistance.

Disclosure of Invention

The invention aims to provide a method for manufacturing a continuous-casting bloom continuous-curvature convex roller. The continuous curvature convex roller body working part profile curve has continuous change of a first derivative, continuous change of a second derivative and continuous change of curvature, and provides a forming method of a transition curve with continuously changing curvature. The continuous curvature convex roller can enable a casting blank in a deformation area to be uniformly deformed, and the occurrence of cracks is reduced; the transition curve of the continuous curvature convex roller can be shortened, and the rolling pressure and the withdrawal resistance can be further reduced.

The technical scheme of the invention is as follows: the method for manufacturing the continuous curvature convex roller of the continuous casting bloom is characterized by comprising the following steps of:

the outer contour curve of the working part of the roll body of the continuous curvature convex roll consists of a first straight line section AB, a first transition curve section BC, a middle straight line section CD, a second transition curve section DE and a second straight line section EF;

the first transition curve segment BC, the first straight line segment AB, the first derivative continuous change, the second derivative continuous change and the curvature continuous change of the middle straight line segment CD form a first transition curve with continuously changing curvature;

similarly, the second transition curve section DE, the middle straight line section CD, the first derivative continuous change, the second derivative continuous change and the curvature continuous change of the second straight line section EF form a second transition curve with continuously changing curvature;

the first transition curve BC and the second transition curve DE are in mirror symmetry;

when the convex roller is manufactured and processed, firstly, a blank is cast according to the shape and the size requirements of the convex roller, and the working part of the roller body is processed according to the shape of the outer contour curve and along the central axis O₁O₂Rotating to obtain a continuous curvature convex roller;

for the existing flat roller, a lug boss can be firstly welded on the working part of the roller body, and the working part of the roller body is machined according to the shape of the outer contour curve and along the central axis O₁O₂Rotating to obtain a continuous curvature convex roller;

the convex roller manufactured by the method for manufacturing the continuous casting bloom continuous curvature convex roller can enable a casting blank in a deformation area to be uniformly deformed and reduce cracks;

the convex roller manufactured by the manufacturing method of the continuous-casting bloom continuous-curvature convex roller has the advantages that the transition curve can be shortened, the rolling pressure can be further reduced, and the withdrawal resistance can be further reduced.

Specifically, the method for forming the transition curve with continuously changing curvature includes the following steps:

establishing a coordinate system, wherein the origin of coordinates is at a middle point O, the two points O, B meet the requirement of continuous second-order derivatives, and the point A meets the requirement of continuous first-order derivatives;

the curve equation of the boss of the convex roller is a curve which is axisymmetric along the central point A, the curve section OA is a curve on the left half side, and the curve section AB is a curve on the right half side;

the curve section OA is used as a left half curve of the boss, the curve section AB is used as a right half curve of the boss, and the middle parts of the curve sections are connected by a horizontal straight line.

Further, the curve equation

The limiting conditions are as follows:

and point O: x is 0:

y＝0； (1)

and (B) point A: x is L/2:

y＝H； (4)

and B, point: x is L:

y＝0； (6)

i.e. a total of 8 constraints;

assuming that the transition curve of the boss is in a polynomial form, because of 8 constraints, the following should be:

y＝a₇x⁷+a₆x⁶+a₅x⁵+a₄x⁴+a₃x³+a₂x²+a₁x+a₀(9)

(1) the formula (8) represents, in place of the formulae (9), (10) and (11): solving an 8-element linear equation simultaneously to obtain:

a₀＝0；a₁＝0；a₂＝0；

a₇＝0；

since the 0, 1 and 2 derivatives of the curve are continuous, the curvature of the curve is continuous and belongs to a smooth curve.

Further, the second transition curve DE may be formed by mirroring the midpoint of the first transition curve BC along the middle straight line segment CD as a center line.

Compared with the prior art, the invention has the advantages that:

1. the continuous curvature convex roller manufactured by the technical scheme can enable a casting blank in a deformation area to deform uniformly, and reduce cracks; by adopting the technical scheme of the invention, the transition curve of the convex roller can be shortened, the rolling pressure can be further reduced, and the blank drawing resistance can be further reduced;

2. the convex roller manufactured by the technical scheme is adopted to carry out solidification tail end soft reduction control, so that the center porosity of a casting blank can be reduced, the center density of the casting blank is further improved, and the internal quality of a rolled material is improved;

3. the convex roller manufactured by the technical scheme is adopted to implement the solidification tail end heavy reduction technology, so that the condition that the solidified blank shells on the two sides generate larger deformation resistance is avoided, the heavy reduction can be implemented on the middle part of a casting blank, the central density of the casting blank is improved, and meanwhile, as the contact area of the convex roller and the casting blank is small, the friction force is reduced, the blank drawing resistance in the continuous casting process of the casting blank is also reduced.

Drawings

FIG. 1 is a schematic view of the profile shape of a male roll of the present invention;

FIG. 2 is a schematic diagram of a horizontal cross-sectional coordinate system of the boss of the present invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The invention aims to provide a light reduction roller capable of sufficiently reducing defects generated on the surface of a rolled material.

Aiming at the purposes, the invention adopts the following technical scheme:

as shown in fig. 1, the profile curve of the working portion of the roll body of the continuous curvature crowned roll of the present invention is comprised of a first straight line segment AB, a first transition curve segment BC, an intermediate straight line segment CD, a second transition curve segment DE and a second straight line segment EF.

The first transition curve segment BC, the first straight line segment AB and the first derivative of the middle straight line segment CD continuously change, the second derivative continuously changes and the curvature continuously changes.

Similarly, the second transition curve segment DE and the intermediate straight line segment CD, the first derivative of the second straight line segment EF continuously changes, the second derivative continuously changes, and the curvature continuously changes.

The forming method of the first transition curve with continuously changing curvature in the technical scheme is as follows:

a coordinate system as shown in fig. 2 is established (the origin of coordinates is at the middle O point, O, B two points satisfy the second derivative continuum, point a satisfies the first derivative continuum).

In the technical scheme, the curve equation of the boss of the convex roller is an axisymmetric curve along the point A at the center, the curve OA is a curve at the left half side, and the curve AB is a curve at the half side. Curve OA is taken as the left half curve of the boss, curve AB is taken as the right half curve of the boss, and the middle is connected by a horizontal straight line.

The curve equation for the first transition curve of the male roll boss is obtained by:

the limiting conditions are as follows:

and point O: x is 0:

y＝0； (1)

and (B) point A: x is L/2:

y＝H； (4)

and B, point: x is L:

y＝0； (6)

i.e. a total of 8 constraints.

Assuming that the transition curve of the boss is in a polynomial form, because of 8 constraints, the following should be:

y＝a₇x⁷+a₆x⁶+a₅x⁵+a₄x⁴+a₃x³+a₂x²+a₁x+a₀(9)

(1) the formula (8) represents, in place of the formulae (9), (10) and (11): solving an 8-element linear equation simultaneously to obtain:

a₀＝0；a₁＝0；a₂＝0；

a₇＝0。

since the 0, 1 and 2 derivatives of the curve are continuous, the curvature of the curve is continuous and belongs to a smooth curve.

The second transition curve DE may be formed by mirroring the first transition curve BC along the midpoint of the middle straight line segment CD as a center line.

The technical scheme adopted by the invention has the beneficial effects that:

according to the technical scheme, the convex roller is used for carrying out solidification tail end soft reduction control and comprehensive application to reduce center porosity of a casting blank, further improve the center density of the casting blank, and improve the internal quality of a rolled material (the casting blank can generate large volume shrinkage in the solidification process, so that the volume shrinkage of the casting blank needs to be compensated by larger reduction amount, and the casting blank can generate deformation resistance in the reduction process and is mainly concentrated on a blank shell solidified on two sides).

The invention adopts the convex roller solidification tail end heavy reduction technology, avoids the blank shells solidified at two sides from generating larger deformation resistance, can implement heavy reduction on the middle part of the casting blank, and improves the central density of the casting blank.

Meanwhile, the contact area between the convex roller and the casting blank is small, and the friction force is reduced, so the casting resistance in the continuous casting process of the casting blank is also reduced.

In addition, the key point is that the continuous curvature convex roller manufactured by the technical scheme is adopted to perform the operation in a light pressing mode, so that the casting blank in a deformation area can be uniformly deformed, and the occurrence of cracks is reduced; the transition curve of the convex roller manufactured by the invention can be shortened, and the rolling pressure and the withdrawal resistance can be further reduced.

When the method is implemented, firstly, a blank is cast according to the shape and the size requirements of the convex roller; working-part working of the roll body according to the outline of figure 1 along the axis O₁O₂Rotating to obtain a continuous curvature convex roller; for the existing flat roller, a boss can be firstly welded on the working part of the roller body, and the working part of the roller body is machined according to the outline shape of a figure 1 and along an axis O₁O₂And (5) rotating to obtain the continuous curvature convex roller.