A method for designing a pass of a seamless tube continuous rolling mill
By rationally designing the roll pass of the seamless steel pipe continuous rolling mill, the problem of scratches on the inner wall of the steel pipe was solved, the pass rate and yield of the steel pipe were improved, and the production cost was reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-07-30
- Publication Date
- 2026-04-10
AI Technical Summary
The existing pass design method in seamless steel pipe continuous rolling mills can easily lead to scratches on the inner wall of the steel pipe during rolling production, especially when producing small-diameter thin-walled pipes. The high rate of defect detection results affects the pass rate and yield of the steel pipes.
A method for designing the pass profile of a seamless steel pipe continuous rolling mill is adopted. By setting the contact angle of the tube bar as a condition, the pass profile area is calculated, and the center coordinates and radii of the bottom arc, the separation arc, and the connecting arc are reasonably designed. The pass profile parameters are iteratively adjusted step by step to meet the accuracy requirements and reduce scratches on the inner wall of the steel pipe.
It effectively reduces scratches on the inner wall of steel pipes, lowers the failure detection rate, improves the pass rate and yield of steel pipes, and reduces production costs.
Smart Images
Figure CN115688292B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of pass design method, especially a kind of continuous rolling pipe mill pass design method. BACKGROUND
[0002] It is known that in the production of seamless steel pipes, often need to adopt to continuous rolling pipe mill, continuous rolling pipe mill has very important significance, it can assist operator to obtain pipe material by rolling. It needs to be noted that, in continuous rolling pipe mill, pass is provided in continuous rolling pipe mill, when using continuous rolling pipe mill, the design of continuous rolling pipe mill pass is very important, the pass of continuous rolling pipe mill will directly affect the quality of pipe material obtained by rolling.
[0003] At present, in the production process of seamless steel pipe continuous rolling mill group, the pass of continuous rolling pipe mill in continuous rolling mill group is usually the pass structure disclosed in the Chinese patent document with publication number CN104209345B, publication date January 11, 2017, and the name of "continuous rolling mill pass design method".
[0004] But because the current continuous rolling pipe mill pass design method considers less about the quality of steel pipe inner wall, the inner wall of continuous rolling steel pipe is more seriously scratched during production when it is used for rolling production, especially when producing small-diameter thin-walled pipes, the probability of scratch on the inner wall of steel pipe is larger, which will greatly increase the detection and injury rate, reduce the pass rate and yield rate of steel pipe, and increase the cost of steel.
[0005] Therefore, in view of the defects and shortcomings of the continuous rolling pipe mill pass design method in the prior art, in order to improve the defects of the existing pass design and improve the quality of the inner wall of the steel pipe, the present application aims to obtain a new seamless steel pipe continuous rolling pipe mill pass design method, which is simple to operate and easy to implement. By reasonably designing the pass of the seamless steel pipe continuous rolling pipe mill, the scratch on the inner wall of the steel pipe can be effectively reduced, the detection and injury rate of the inner wall scratch can be reduced, and the surface finish of the inner surface of the steel pipe can be ensured. SUMMARY
[0006] The present application aims to provide a seamless steel pipe continuous rolling pipe mill pass design method, which is simple to operate and easy to implement. By reasonably designing the pass of the seamless steel pipe continuous rolling pipe mill, the size parameters of the pass can be obtained by calculating the pass area with the pipe rod contact angle as the set condition. The seamless steel pipe continuous rolling pipe mill pass design method can effectively reduce the scratch on the inner wall of the steel pipe, reduce the detection and injury rate of the inner wall scratch, ensure that the inner surface of the steel pipe can obtain good surface finish, and improve the pass rate and yield rate of the steel pipe, reduce the amount of waste products and cost generated during production process.
[0007] In order to achieve the above object, the present application provides a seamless tube continuous rolling mill pass design method, wherein the pass comprises a groove bottom arc, a separation arc and a connecting arc which are sequentially connected from the center line of the pass; the seamless tube continuous rolling mill pass design method comprises the following steps for each stand of the continuous rolling mill:
[0008] 100: calculating the theoretical cross-sectional area of the steel at the outlet of each stand;
[0009] 200: assigning initial values of the groove bottom arc radius and the separation arc radius to determine the outer profile and the inner profile of the steel tube at the roll gap, and obtaining the actual cross-sectional area of the steel tube at the outlet of each stand based on the outer profile and the inner profile of the steel tube at the roll gap;
[0010] 300: calculating the actual value of the tube-bar contact angle φ: wherein k is a coefficient, the value of k is 1-6, the value of k is related to the wall thickness, the elongation coefficient and the separation ratio (the ratio of the separation arc radius to the groove bottom arc radius), and the value of k decreases with the increase of the wall thickness and the separation ratio, and increases with the increase of the elongation coefficient;
[0011] 400: comparing the difference between the actual value of the tube-bar contact angle and the set value of the tube-bar contact angle with a preset first threshold value, if the difference is less than or equal to the preset first threshold value, the next step is performed; if the difference is greater than the preset first threshold value, the separation arc radius is increased, and the increased separation arc radius is taken as the initial value of the separation arc radius, and step 200 is performed;
[0012] 500: comparing the difference between the actual cross-sectional area of the steel tube and the theoretical cross-sectional area of the steel with a preset second threshold value, if the difference is less than or equal to the preset second threshold value, the steps of the next stand are performed, until all the steps of all the stands are completed; if the difference is greater than the preset second threshold value, the groove bottom arc radius is decreased, and the decreased groove bottom arc radius is taken as the initial value of the groove bottom arc radius, and step 200 is performed.
[0013] In the present application, the pass structure of the seamless tube continuous rolling mill is composed of the groove bottom arc, the separation arc, the connecting arc and the roll gap which are sequentially connected from the center line of the pass, and the pass design method of the seamless tube continuous rolling mill can obtain the center coordinates and the radius of each arc by reasonable operation design, so as to determine the pass.
[0014] Further, in the pass design method of the seamless tube continuous rolling mill, in step 100:
[0015] calculating the cross-sectional area S0 of the blank based on the known outer diameter D0 of the blank and the wall thickness WT0 of the blank: S0=(D0-WT0)×WT0;
[0016] Based on the known average elongation coefficient λ of each rack i Obtain the theoretical cross-sectional area S of the steel tube at the exit of each rack. i :S i =S i-1 ×λ i , where i = 1, 2, ..., n, which represents the parameters corresponding to the i-th stand, and n represents the number of stands in the continuous rolling mill.
[0017] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, step 200 includes:
[0018] 201: Based on the initial values of the bottom arc radius and the detachment arc radius, obtain the center of the bottom arc, the center of the detachment arc, the radius of the connecting arc, and the center of the connecting arc;
[0019] 202: Calculate and obtain the radius of the steel pipe at the roll gap;
[0020] 203: Determine the outer and inner contours of the steel pipe at the roll gap based on the radius of the steel pipe at the roll gap;
[0021] 204: Obtain the actual cross-sectional area of the steel pipe at the exit of each frame based on the outer and inner contours of the steel pipe at the roll gap.
[0022] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, in step 201:
[0023] The eccentricity Ecc of the slot bottom arc corresponding to the i-th rack is calculated using the following formula. i Ecc i =R1 i ×e i R1 i e represents the initial value of the groove bottom arc radius corresponding to the i-th rack. i This represents the known eccentricity coefficient corresponding to the i-th rack;
[0024] Based on the initial value of the bottom arc radius, the initial value of the departure arc radius, and the bottom arc eccentricity Ecc i The center of the bottom arc and the center of the detachment arc are determined based on geometric relationships;
[0025] Based on the known geometric relationship between the first separation angle and the roll gap, the radius and center of the connecting arc are obtained.
[0026] In the above-described technical solutions of the present invention, under certain embodiments, the radius and center of the connecting arc can be obtained by CAD drawing software based on the known geometric relationship between the first separation angle and the roll gap.
[0027] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, in step 202: the radius OB of the steel pipe at the roll gap corresponding to the i-th stand is calculated based on the following formula. i :OBi=(R1 i-1 -Ecc i-1 )×B i B i This represents the known expansion coefficient corresponding to the i-th rack.
[0028] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, in step 203:
[0029] Based on the radius OB of the steel pipe at the roll gap i Determine the intersection point P2 between the outer surface of the steel pipe at the roll gap and the centerline of the roll gap;
[0030] The separation point P1 between the steel pipe and the roll is determined based on the known contact angle of the tube roll corresponding to the i-th frame.
[0031] Determine the outer contour of the steel pipe at the roll gap based on P1 and P2;
[0032] Based on the outer contour and the wall thickness of the steel pipe, the inner contour of the steel pipe at the roll gap is determined.
[0033] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, the first threshold is 0.5%.
[0034] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, the second threshold is 0.5%.
[0035] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, in step 400, the departure arc radius is increased by 0.05 mm.
[0036] Furthermore, in the seamless steel pipe continuous rolling mill pass design method of the present invention, in step 500, the bottom arc radius of the groove is reduced by 0.05 mm.
[0037] The seamless steel pipe continuous rolling mill pass design method described in this invention has the following advantages and beneficial effects compared with the prior art:
[0038] The seamless steel pipe continuous rolling mill pass design method described in this invention is simple to operate and easy to implement. By rationally designing the pass pattern of the seamless steel pipe continuous rolling mill, it can alleviate the problem of scratches on the inner surface of the steel pipe caused by the accumulation of iron oxide scale from the lubricant on the inner wall during the production of seamless steel pipes using existing continuous rolling mills. This seamless steel pipe continuous rolling mill pass design method is convenient, fast, and accurate, and can obtain the pass pattern parameters by calculating the pass pattern area using the tube-bar contact angle as a set condition.
[0039] The seamless pipe continuous rolling mill pass design method can effectively reduce the scratch on the inner wall of the steel pipe, reduce the flaw detection report rate caused by the scratch on the inner wall surface of the steel pipe, ensure that the inner surface of the steel pipe can obtain good surface finish, can improve the qualified rate and yield of the steel pipe, and reduce the waste product amount and cost generated in the production process. BRIEF DESCRIPTION OF DRAWINGS
[0040] Figure 1 It is a schematic diagram of the pass section of the rolling roller of the seamless pipe continuous rolling mill.
[0041] Figure 2 The operation flowchart of the seamless pipe continuous rolling mill pass design method is schematically shown. DETAILED DESCRIPTION
[0042] The seamless pipe continuous rolling mill pass design method will be further explained and described below in combination with specific embodiments, however, the explanation and description does not constitute improper limitation on the technical scheme of the present application.
[0043] The present application provides a seamless pipe continuous rolling mill pass design method, which can effectively alleviate the problem that the oxidation scale of the lubricant on the inner wall surface of the steel pipe is concentrated and causes the scratch on the inner surface during the production of the seamless steel pipe by the existing continuous rolling mill.
[0044] Figure 1 It is a schematic diagram of the pass section of the rolling roller of the seamless pipe continuous rolling mill.
[0045] As Figure 1 shown in the present application, the pass structure of the seamless pipe continuous rolling mill is composed of a groove bottom arc, a separation arc, a connecting arc and a roller gap S in sequence from the center line of the pass, the radius of the groove bottom arc can be represented as R1, the radius of the separation arc can be represented as R2, and the radius of the connecting arc can be represented as R5. Figure 1 The shadow part shown in the figure represents the cross section of the steel pipe on the pass section, the upper part of the shadow represents the continuous rolling pass, and the lower part of the shadow represents the mandrel, and Ecc represents the eccentricity of the groove bottom arc.
[0046] Further referring to Figure 1 It can be seen that, in the present application, the pipe roller contact angle a roll refers to the included angle between the positions where the left and right sides of the steel pipe and the roller surface initially separate at the pass section, and the separation point of the steel pipe and the roller is represented as P1 point; the pipe rod contact angle a mnd refers to the included angle between the positions where the left and right sides of the steel pipe and the mandrel initially separate at the pass section, and the intersection point of the outer surface of the steel pipe and the center line of the roller gap is represented as P2 point.
[0047] The output result of the seamless steel tube continuous piercer pass design method is the center coordinates and radius of the groove bottom arc, the separation arc and the connecting arc, so that the pass size can be quickly, conveniently and accurately obtained. roll and the pipe rod contact angle a mnd , the accuracy requirement of the pass design is met through step-by-step iteration, the steel pipe inner surface has good surface finish, and the effect of reducing the inner wall scratch flaw detection failure rate can be achieved.
[0048] Figure 2 The operation flowchart of the seamless steel tube continuous piercer pass design method is schematically shown.
[0049] As Figure 2 shown, in the seamless steel tube continuous piercer pass design method, the set parameters of the pass design can be input first, and the input set parameters can include the blank pipe outer diameter D0 and the wall thickness WT0, the rack number i of the continuous piercer, the pass radius D last and the minimum nominal wall thickness WT last (or the mandrel cold state radius d cool ), and the average elongation coefficient λ i , the eccentricity coefficient e i , the first separation angle a1, the pipe roller contact angle a roll and the pipe rod contact angle a mnd , the spread coefficient B i , the connecting angle and the roll gap of each rack.
[0050] When the seamless steel tube continuous piercer pass design method is used, the following steps 100-500 are performed for each rack of the continuous piercer to obtain the pass of the rack.
[0051] 100: Calculate the steel management theoretical cross-sectional area at the outlet of each rack.
[0052] In the above step 100 of the present application, the cross-sectional area S0 of the blank pipe can be calculated according to the known blank pipe outer diameter D0 and the blank pipe wall thickness WT0 by using the following formula (1):
[0053] S0=(D0-WT0)×WT0 (1)
[0054] Correspondingly, the steel management theoretical cross-sectional area S i at the outlet of each rack can be calculated according to the known average elongation coefficient λ i of each rack by using the following formula (2):
[0055] S i =S i-1 ×λ i (2)
[0056] In the above formula (2), i = 1, 2, … n, which represents the parameter corresponding to the i th rack; n represents the number of racks of the continuous pipe mill.
[0057] 200: Assigning the initial value of the groove bottom arc radius R1 i and the separation arc radius R2 i The initial value is used to determine the outer profile and inner profile of the steel pipe at the roll gap, and the actual cross-sectional area of the steel pipe at the outlet of each rack is obtained based on the outer profile and inner profile of the steel pipe at the roll gap.
[0058] In the present application, the above step 200 of the present application can further include the following steps 201-204:
[0059] Step 201: Obtaining the groove bottom arc center, the separation arc center, the connecting arc radius and the connecting arc center according to the initial value of the groove bottom arc radius and the initial value of the separation arc radius.
[0060] It should be noted that in step 201, the groove bottom arc eccentricity Ecc i of the i th rack can be calculated according to the following formula (3):
[0061] Ecc i = R1 i × e i (3)
[0062] In the above formula (3), R1 i represents the initial value of the groove bottom arc radius corresponding to the i th rack, and e i represents the known eccentricity coefficient corresponding to the i th rack.
[0063] Correspondingly, in step 201, based on the initial value of the groove bottom arc radius, the initial value of the separation arc radius and the groove bottom arc eccentricity Ecc i , the groove bottom arc center and the separation arc center can be effectively determined according to the geometric relationship; according to the known first separation angle and the geometric relationship of the roll gap, the connecting arc radius and the connecting arc center can be obtained.
[0064] Step 202: Calculating the radius of the steel pipe at the roll gap.
[0065] In step 202 of the present application, the spread coefficient corresponding to the rack can be used to calculate the radius of the steel pipe at the roll gap. In the present application, the radius OB i of the steel pipe at the roll gap corresponding to the i th rack can be calculated according to the following formula (4):
[0066] OBi= (R1 i-1 -Ecc i-1 )× B i (4)
[0067] In the above formula (4), B i represents the known spread factor corresponding to the i-th housing; Ecc i-1 represents the slot bottom arc eccentricity corresponding to the i-1-th housing; R1 i-1 represents the initial value of the slot bottom arc radius corresponding to the i-1-th housing.
[0068] Step 203: determining the outer profile and the inner profile of the steel pipe at the roll gap based on the radius of the steel pipe at the roll gap.
[0069] In step 203 of the present application, according to the radius OB i of the steel pipe at the roll gap, the intersection P2 of the outer surface of the steel pipe at the roll gap and the center line of the roll gap can be determined; according to the known contact angle a roll of the pipe roll corresponding to the i-th housing, the disengagement point P1 of the steel pipe and the roll can be determined.
[0070] Correspondingly, according to the positions of the disengagement point P1 and the intersection P2, the outer profile (equivalent to a circular arc) of the steel pipe at the roll gap can be further determined; and according to the outer profile of the steel pipe at the roll gap and the wall thickness of the steel pipe, the inner profile of the steel pipe at the roll gap can be effectively determined.
[0071] Step 204: obtaining the actual cross-sectional area M of the steel pipe at the exit of each housing based on the outer profile and the inner profile of the steel pipe at the roll gap.
[0072] 300: calculating the actual value φ of the pipe roll contact angle: wherein k is a coefficient, the value of k is 1-6, the size of k is related to the wall thickness, the elongation factor and the disengagement ratio (the ratio of the disengagement arc radius to the slot bottom arc radius), and the trend decreases with the increase of the wall thickness and the disengagement ratio, and increases with the increase of the elongation factor.
[0073] 400: comparing the difference between the actual value φ of the pipe roll contact angle and the set value a mnd of the pipe roll contact angle with the first threshold value Δ1, if the difference is less than or equal to the first threshold value Δ1, then the next step 500 is performed; if the difference is greater than the first threshold value Δ1, the disengagement arc radius is increased, in the present embodiment, the disengagement arc radius can be increased by 0.05 mm, and the increased disengagement arc radius is taken as the initial value of the disengagement arc radius, and the step 200 is executed again.
[0074] In the above step 400 of the present application, the disengagement arc radius is changed to iterate until the difference between the actual value φ of the pipe roll contact angle and the set value a mnd of the pipe roll contact angle satisfies the requirement that it is less than or equal to the first threshold value Δ1.
[0075] 500: comparing the actual cross-sectional area M of the steel pipe with the theoretical cross-sectional area Si The difference is compared with a preset second threshold value Δ2, if the difference is less than or equal to the preset second threshold value Δ2, the pass design of the rack is completed, and the next rack is executed until all the racks are executed completely; if the difference is greater than the preset second threshold value Δ2, the groove bottom arc radius needs to be reduced, in the embodiment, the groove bottom arc radius can be reduced by 0.05 mm, and the reduced groove bottom arc radius is taken as the initial value of the groove bottom arc radius, and the step 200 is returned to be executed again.
[0076] In the step 500 of the present application, the groove bottom arc radius is changed to iterate, the error is reduced, and the actual cross-sectional area M of the steel pipe and the theoretical cross-sectional area S of the steel pipe i satisfy the requirement that the difference is less than or equal to the preset second threshold value Δ2. After the requirement is satisfied, the center coordinates and the radius of the groove bottom arc, the separation arc and the connecting arc can be obtained, so that all the parameters of the pass of the rack can be determined.
[0077] Referring to Figure 2 It can be seen that in the flowchart shown in Figure 2 , "ng" can represent the total number of racks.
[0078] Correspondingly, for each rack of the continuous rolling pipe mill, the above steps 100-500 are executed, and after the calculation of the first rack is completed, the pass parameters of the subsequent racks are calculated in the same steps until the calculation of the pass parameters of all the racks is completed.
[0079] It should be noted that in some embodiments, the first threshold value Δ1 in the step (4) of the present application can be set to 0.5%; correspondingly, in some embodiments, the second threshold value Δ2 in the step (5) of the present application can also be set to 0.5%.
[0080] As can be seen from the above, the seamless steel pipe continuous rolling pipe mill pass design method of the present application is simple and easy to operate and realize, and through reasonable operation and design of the seamless steel pipe continuous rolling pipe mill pass, the problem of scratches on the inner surface of the steel pipe caused by the oxidation of the lubricant iron scale on the inner surface of the steel pipe during the production of the seamless steel pipe by the existing continuous rolling pipe mill can be alleviated. The seamless steel pipe continuous rolling pipe mill pass design method is convenient, fast and accurate, and can obtain the parameters of the pass through the calculation of the pass area by taking the pipe rod contact angle as a set condition.
[0081] The seamless steel pipe continuous rolling pipe mill pass design method of the present application can effectively reduce the scratches on the inner wall of the steel pipe, reduce the detection and report of the scratches caused by the scratches on the inner surface of the steel pipe, so as to ensure that the inner surface of the steel pipe can obtain good surface finish, which can improve the qualified rate and yield of the steel pipe, and reduce the amount of waste products and costs generated in the production process.
[0082] In addition, it should be noted that the seamless steel tube continuous rolling pipe mill pass design method can be conveniently calculated by compiling a calculation program.
[0083] It should be noted that the combination of the technical features in the case is not limited to the combination of the claims in the case or the combination of the embodiments in the case. All the technical features recorded in the case can be freely combined or combined in any way, unless contradictory to each other.
[0084] It should also be noted that the above-mentioned embodiments are only specific embodiments of the present application. Obviously, the present application is not limited to the above-mentioned embodiments, and similar changes or modifications made by the skilled in the art from the disclosure of the present application are directly derived or easily conceived, and all should belong to the protection scope of the present application.
Claims
1. A method of pass design for seamless steel pipe continuous piercer, wherein the pass comprises, in order from the center line of the pass, a groove bottom arc, a separation arc, and a connection arc; characterized in that, The seamless steel tube continuous rolling pipe mill pass design method comprises the following steps for each stand of the continuous rolling pipe mill: 100: calculating the theoretical cross-sectional area of the steel at the exit of each stand; 200: assigning initial values of the groove bottom arc radius and the separation arc radius to determine the outer profile and the inner profile of the steel tube at the roll gap, and obtaining the actual cross-sectional area of the steel tube at the exit of each stand based on the outer profile and the inner profile of the steel tube at the roll gap; 300: Calculate the actual value of the tube rod contact angle φ: wherein k is a coefficient, and has a value of 1-6; 400: comparing the difference between the actual value of the pipe rod contact angle and the set value of the pipe rod contact angle with a preset first threshold value, if the difference is less than or equal to the preset first threshold value, the next step is performed; if the difference is greater than the preset first threshold value, the separation arc radius is increased, and the increased separation arc radius is taken as the initial value of the separation arc radius, and step 200 is performed; 500: comparing the difference between the actual cross-sectional area of the steel tube and the theoretical cross-sectional area of the steel with a preset second threshold value, if the difference is less than or equal to the preset second threshold value, the next step of the next stand is performed until all the steps of all the stands are completed; if the difference is greater than the preset second threshold value, the groove bottom arc radius is reduced, and the reduced groove bottom arc radius is taken as the initial value of the groove bottom arc radius, and step 200 is performed.
2. The seamless pipe mill pass design method as recited in claim 1, wherein, In step 100: The cross-sectional area S0 of the blank is calculated based on the known outer diameter D0 of the blank and the wall thickness WT0 of the blank: S0 = (D0-WT0) x WT0; According to the known average elongation coefficient λ of each stand i , the theoretical cross-sectional area S of the steel corresponding to the outlet of each stand is obtained i : S i = S i-1 × λ i , where i = 1, 2, … n, which represents the parameters corresponding to the i-th stand, and n represents the number of stands of the continuous pipe mill.
3. The seamless pipe mill pass design method as recited in claim 1, wherein, Step 200 comprises: 201: obtaining the center of the groove bottom arc, the center of the separation arc, the connecting arc radius and the center of the connecting arc based on the initial value of the groove bottom arc radius and the initial value of the separation arc radius; 202: calculating the radius of the steel tube at the roll gap; 203: determining the outer profile and the inner profile of the steel tube at the roll gap based on the radius of the steel tube at the roll gap; 204: obtaining the actual cross-sectional area of the steel tube at the exit of each stand based on the outer profile and the inner profile of the steel tube at the roll gap.
4. The seamless pipe mill pass design method as recited in claim 3, wherein, In step 201: The slot bottom arc eccentricity Ecc corresponding to the ith rack is calculated according to the following formula i : Ecc i = R1 i × e i , wherein R1 i represents the initial value of the slot bottom arc radius corresponding to the ith rack, e i represents the known eccentricity coefficient corresponding to the ith rack; based on the initial value of the groove bottom arc radius, the initial value of the escape arc radius, and the eccentricity Ecc of the groove bottom arc i determine the center of the groove bottom arc and the center of the escape arc according to geometric relationships; The connecting arc radius and the center of the connecting arc are obtained based on the geometric relationship between the first separation angle and the roll gap.
5. The seamless pipe mill pass design method as recited in claim 4, wherein, In step 202: the radius of the steel pipe at the roll gap corresponding to the ith rack is calculated based on the following formula i : OB i = (R1 i-1 -Ecc i-1 ) x B i , wherein B i represents the spread coefficient corresponding to the ith rack which is known.
6. The seamless pipe mill pass design method as recited in claim 5, wherein, In step 203: the radius of the steel pipe at the roll gap i determining the intersection P2 of the outer surface of the steel pipe at the roll gap and the center line of the roll gap; The separation point P1 of the steel tube and the roll is determined based on the contact angle of the pipe roll corresponding to the i-th stand; The outer profile of the steel tube at the roll gap is determined based on P1 and P2; The inner profile of the steel tube at the roll gap is determined based on the outer profile and the wall thickness of the steel tube.
7. The seamless pipe mill pass design method as recited in claim 1, wherein, The first threshold value is 0.5%.
8. The seamless pipe mill pass design method as recited in claim 1, wherein, The second threshold value is 0.5%.
9. The seamless pipe mill pass schedule method as recited in claim 1, wherein, In step 400, the separation arc radius is increased by 0.05 mm.
10. The seamless pipe mill pass design method as recited in claim 1, wherein, In step 500, the groove bottom arc radius is reduced by 0.05 mm.
Citation Information
Patent Citations
Continuous rolling mill pass design method
CN104209345B