CN109622905B - A Design Method of High-order Polynomial Curve Convex Roller for Bloom Continuous Casting Tensile Leveler - Google Patents

Abstract

The invention belongs to the field of bloom continuous casting production, and in particular relates to a design method for a high-order polynomial curve convex roll of a bloom continuous casting tension leveler. The design feature of the high-order polynomial convex roll of the tension leveler of the present invention is that the roll body adopts a segmented curve, which includes an edge area, a high-order polynomial curve area and a flat roll area. ‑5th degree polynomial curve is drawn, the edge area is a straight line that joins the high-degree polynomial curve area, and the flat roller area is convex relative to the edge area, which is a straight line that joins the other end of the high-degree polynomial curve area. The design method for the high-order polynomial curve convex roll of the bloom continuous casting tension leveler provided by the invention can greatly improve the central density of the slab, so that the central porosity (segregation) of the slab can be effectively controlled, and the smooth curve transition can Effectively avoid surface cracks caused by stress concentration in the transition area, enhance the control ability of the shape of the slab, and at the same time digitize the curve in the transition area to facilitate processing and manufacturing.

Description

A Design Method of High-order Polynomial Curve Convex Roller for Bloom Continuous Casting Tensile Leveler

technical field

The invention belongs to the field of bloom continuous casting production, and in particular relates to a design method for a high-order polynomial curve convex roll of a bloom continuous casting tension leveler.

Background technique

In the production process of bloom continuous casting, the casting roll of the stretch leveler is used to complete the solidification end reduction process. In order to apply a large reduction amount, most of the bloom continuous casting stretch levelers need to improve the capacity of the hydraulic equipment to improve the blank. capacity, and its renovation costs are relatively large. According to the solidification characteristics of the bloom, its liquid core is conical, so during the pressing process at the end of solidification, the deformation resistance of the billet is mainly concentrated on the two sides of the billet shell. Therefore, if the casting billet with a convex middle can be used for rolling, the rolling force can be concentrated in the central area of the billet, thereby significantly improving the rolling efficiency.

According to this concept, researchers at home and abroad have proposed a variety of convex roller designs, usage methods and related process implementations. For example, scholars in Pohang, South Korea proposed a double 1/4 circular transition arc convex roller (ISIJ International, Vol.52 (2012), No.7, pp.1266-1272). The main features of this structure are: the 300mm area in the middle of the roller with a diameter of 450mm is a convex surface, and the double 1/4 circular transition arc with a radius of 40mm between the convex surface and the plane. This structure can significantly improve the extrusion capacity of the liquid core. It is reported that the reduction of 14mm after the transformation can reach the technological effect of the reduction of 30mm before the transformation. However, this design mechanism will inevitably lead to stress concentration at the position of the double 1/4 circular transition arc, resulting in cracks in the corners of the slab.

The patent application CN107537987A "Convex Convex Combination of Continuous Casting Alloy Steel Blooms and Heavy Reduction Process" proposes convex rolls with gradual curvature with bosses and constant curvature convex rolls without bosses for continuous casting alloy steel blooms. The quality problem of the core of the casting billet; the patent application CN106001475A "Continuously Casting Alloy Steel Blooms with Gradient Curvature Convex Roll and Heavy Reduction Process", proposes the use of gradual curvature convex equipment and heavy reduction process to produce high-profile 380mm × 490mm Alloy steel continuous casting billet, the low magnification of its inspection shows that the quality of the core part of the continuous casting billet has been significantly improved and the quality is stable.

The double arc type and gradual curvature type used in the above researches are difficult to process due to the lack of equations and the roll curve cannot be effectively controlled. At present, the improvement of the core of the billet by the convex roll is well known. There are still shortcomings in the specific design method of the roller.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a method for designing a high-order polynomial curve convex roll of a bloom continuous casting draw-leveler, which can ensure the stable implementation of the process and the quality of the continuous casting slab. , the reasonable design of the convex roller is conducive to the processing and manufacturing and the implementation of various reduction processes.

In order to achieve the above object, technical scheme of the present invention is as follows:

A method for designing a high-order polynomial curve convex roll of a bloom continuous casting machine. composition;

The high-order polynomial curve area curve is drawn from the highest-order polynomial curve of the 3-5th degree;

The edge region is a straight line joined with the high-order polynomial curve region, and the flat roller region is convex relative to the edge region and is a straight line joined with the other end of the high-order polynomial curve region.

A method for designing a high-order polynomial curve convex roll of a bloom continuous casting draw-leveler as claimed in claim 1, the preferred solution is a polynomial curve of a piecewise function, and the roll shape function is as follows:

In the formula, y(x) is the roll shape function of the convex roll body, and the unit is mm;

y ₁ (x) is the constant value roll shape function of the left edge area of the roll body, y ₁ (x)=l _c1 unit is mm;

y ₂ (x) is the 3-5th degree polynomial roll shape function in the high-order polynomial curve area on the left side of the roll body,

y ₂ (x)=A ₃ x ³ +A ₂ x ² +A ₁ x+c

Or y ₂ (x)=A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c

Or y ₂ (x)=A ₅ x ⁵ +A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c in mm;

y ₃ (x) is the constant roll shape function in the flat roll area of the roll body, y ₃ (x)=l _q unit is mm;

y ₄ (x) is the 3-5th degree polynomial roll shape function in the high-order polynomial curve area on the right side of the roll body,

y ₄ (x)=B ₃ x ³ +B ₂ x ² +B ₁ x+c

or y ₄ (x)=B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c

Or y ₄ (x)=B ₅ x ⁵ +B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c in mm;

y ₅ (x) is the constant value roll shape function of the right edge area of the roll body, y ₅ (x)=l _c2 unit is mm;

x is the coordinate of the roller body, the unit is mm;

A ₁ , A ₂ , A ₃ , A ₄ , and A ₅ are roll shape coefficients, in mm;

B ₁ , B ₂ , B ₃ , B ₄ , B ₅ are roll shape coefficients, in mm;

c is the intercept, in mm;

s ₀ is the horizontal offset from the origin, in mm;

l The horizontal length of the left edge area of _c1 , in mm;

l The horizontal length of the right edge area of _c2 , in mm;

l The horizontal length of the high-order polynomial curve area on the left side of _s1 , in mm;

l The horizontal length of the high-order polynomial curve area on the right side of _s2 , in mm;

l _q Horizontal length of flat roller area, in mm;

l is the length of the work roll body, in mm;

Through the given work roll body length l, the horizontal length of the left edge area l _c1 , the horizontal length of the right edge area l _c2 , the horizontal length of the left high-order polynomial curve area l _s1 , the horizontal length of the right high-order polynomial curve area l _s2 , the horizontal length _lq of the flat roll area, the roll diameter D, and the shaft diameter d, basically draw the convex roll, and then draw the high-order polynomial curve shape of the convex roll according to the actual process requirements on site. , perform polynomial fitting on the drawn curve, and select the highest degree 3-6 polynomial curve according to actual processing requirements to further determine A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , B ₁ , B ₂ , B ₃ , B ₄ , B ₅ , c and other parameters, the horizontal offset of s ₀ from the origin can be selected according to the actual processing requirements;

According to the above formulas and the parameters selected by on-site processing, the convex roll profile curve can be determined and processed.

The beneficial effects of the invention are as follows: the central density of the slab can be greatly improved, so that the central porosity (segregation) of the slab can be effectively controlled, and the smooth curve transition can effectively avoid surface cracks caused by stress concentration in the transition zone, and enhance the anti-corrosion effect. The ability to control the shape of the billet, and at the same time digitize the curve of the transition area to facilitate processing and manufacturing.

Description of drawings

Figure 1 is a structural diagram of a convex roller;

Figure 2 shows the high-order polynomial curve area on the left side of the work roll body;

Figure 3 shows the high-order polynomial curve area on the right side of the work roll body.

Detailed ways

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Example 1

As shown in Figure 1, when designing the roll shape, the length of the work roll body l=500mm, the horizontal length of the left and right edge areas l _c1 =l _c2 =110mm, the horizontal length l of the left and right high-order polynomial curve areas _s1 =l _s2 =70mm, the horizontal length of the flat roll area _lq =140mm, the roll diameter D = 560mm, the shaft diameter d = 500mm, the horizontal offset from the origin s ₀ =0, the next step is to combine the given parameters to determine the higher order polynomial Curve area to draw.

As shown in Figures 2 and 3, extract the shape of the roll body in the high-order polynomial curve area of the work roll, and fit the roll shape function to obtain the roll shape function:

Where: y ₂ (x)=A ₃ x ³ +A ₂ x ² +A ₁ x+c

Or y ₂ (x)=A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c

Or y ₂ (x)=A ₅ x ⁵ +A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c

y ₄ (x)=B ₃ x ³ +B ₂ x ² +B ₁ x+c

or y ₄ (x)=B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c

or y ₄ (x)=B ₅ x ⁵ +B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c

The above-mentioned embodiments are only preferred specific implementations of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art can obviously obtain the technical solutions within the technical scope disclosed in the present invention. Simple changes or equivalent replacements all fall within the protection scope of the present invention.

Claims (1)

1. a method for designing a high-order polynomial curve convex roll of a bloom continuous casting machine, it is characterized in that: the roll body of the high-order polynomial curve convex roll of the stretch leveling machine adopts a segmented curve, which comprises an edge area, a high-order polynomial curve, and a The polynomial curve area is composed of the flat roll area; The high-order polynomial curve area curve is drawn from the highest-order polynomial curve of the 3-5th degree; The edge area is a straight line joined with the high-order polynomial curve area, and the flat roller area is convex relative to the edge area, and is a straight line joined with the other end of the high-order polynomial curve area; A polynomial curve of a piecewise function with a roll shape function as follows:

In the formula, y(x) is the roll shape function of the convex roll body, and the unit is mm; y ₁ (x) is the constant value roll shape function of the left edge area of the roll body, y ₁ (x)=l _c1 unit is mm; y ₂ (x) is the 3-5th degree polynomial roll shape function in the high-order polynomial curve area on the left side of the roll body, y ₂ (x)=A ₃ x ³ +A ₂ x ² +A ₁ x+c Or y ₂ (x)=A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c Or y ₂ (x)=A ₅ x ⁵ +A ₄ x ⁴ +A ₃ x ³ +A ₂ x ² +A ₁ x+c in mm; y ₃ (x) is the constant roll shape function in the flat roll area of the roll body, y ₃ (x)=l _q unit is mm; y ₄ (x) is the 3-5th degree polynomial roll shape function in the high-order polynomial curve area on the right side of the roll body, y ₄ (x)=B ₃ x ³ +B ₂ x ² +B ₁ x+c or y ₄ (x)=B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c Or y ₄ (x)=B ₅ x ⁵ +B ₄ x ⁴ +B ₃ x ³ +B ₂ x ² +B ₁ x+c in mm; y ₅ (x) is the constant value roll shape function of the right edge area of the roll body, y ₅ (x)=l _c2 unit is mm; x is the coordinate of the roller body, the unit is mm; A ₁ , A ₂ , A ₃ , A ₄ , and A ₅ are roll shape coefficients, in mm; B ₁ , B ₂ , B ₃ , B ₄ , and B ₅ are roll shape coefficients, in mm; c is the intercept, in mm; s ₀ is the horizontal offset from the origin, in mm; l The horizontal length of the left edge area of _c1 , in mm; l The horizontal length of the right edge area of _c2 , in mm; l The horizontal length of the high-order polynomial curve area on the left side of _s1 , in mm; l The horizontal length of the high-order polynomial curve area on the right side of _s2 , in mm; l _q Horizontal length of flat roller area, in mm; l is the length of the work roll body, in mm; Through the given work roll body length l, the horizontal length of the left edge area l _c1 , the horizontal length of the right edge area l _c2 , the horizontal length of the left high-order polynomial curve area l _s1 , the horizontal length of the right high-order polynomial curve area l _s2 , the horizontal length _lq of the flat roll area, the roll diameter D, and the shaft diameter d, basically draw the convex roll, and then draw the high-order polynomial curve shape of the convex roll according to the actual process requirements on site. , perform polynomial fitting on the drawn curve, and select the highest degree 3-5 polynomial curve according to actual processing requirements to further determine A ₁ , A ₂ , A ₃ , A ₄ , B ₁ , B ₂ , B ₃ , B ₄ , c parameter, the horizontal offset of s ₀ from the origin is selected according to the actual processing requirements; According to the above formulas and the parameters selected by on-site processing, the convex roll profile curve is determined and processed.

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