CN105964697A - Design method for high-precision fine grain groove diagonal rolling roller - Google Patents

Abstract

The invention discloses a design method for a high-precision fine grain groove diagonal rolling roller. The design method includes the following steps that S1, the sizes of a diagonal rolled piece and a rod material are designed, wherein the machining allowance and the thermal expansion effect are considered, and the rolling size of a part is calculated; and the diameter expansion effect in the forming process is considered, and the diameter of the rod material is determined; S2, basic parameters of the diagonal rolling roller are designed, wherein based on empirical data and relational expressions of an existing technology, the basic parameters of the roller are determined; S3, the height changing characteristics of the convex edge of the diagonal rolling roller are designed, wherein on the premise that it is guaranteed that the rolled piece is stably bitten in, design is performed based on the uniform deformation principle of harmony materials; and S4, the width changing characteristics of the convex edge of the diagonal rolling roller are designed, wherein design is performed based on the principle of adapting to the axial extension of a connection neck. By means of the design method, the height and the width of the convex edge of the diagonally-rolled groove type can be reasonably designed, it is facilitated that the deformation state of the rolled piece adapts to the groove type, the harmony materials uniformly deform, and the better forming precision and grain refinement degree are acquired.

Description

The thin geode type oblique roller rolling method for designing of a kind of high accuracy

Technical field

The invention belongs to turn round Technology of Plastic Processing field, be specifically related to the thin geode type oblique roller rolling design of a kind of high accuracy Method, is used for improving revolving parts screw groove diagonal rolling forming accuracy and the crystal grain refinement journeys such as spherical, cylindrical or conical Degree.

Background technology

Screw groove diagonal rolling technique (abbreviation oblique milling) is that a kind of revolving parts advanced person such as spherical, cylindrical, conical returns Turn plastic forming technology, compared to tradition forging and stamping, casting and turning process, there is high-quality, energy-conservation, material-saving, efficiently etc. the most excellent Point, is widely used in the figuration manufacture of the revolving parts such as ball milling steel ball, bearing steel ball and roller.In screw groove diagonal rolling technique, Reasonably grooving of roll is premise and the important leverage of rolling high precision qualified products.

In roll pass geometry, the variation characteristic of spiral ridge height and width decides rolled piece roll form process Middle deformation pattern and metal flow mold-filling capacity, be the key parameter of grooving of roll.Traditional oblique roller rolling hole type design In method, fin height variation feature is limited to the process technology of roll, is generally reduced to by the change design of straight line rule, and convex The variation characteristic of rib width is then to select based on empirical data, and both of which deforms during the most preferably combining oblique roll process Feature and law of metal flow carry out appropriate design.Additionally, the method for tradition fin width empirically data primary election design, need Carrying out check repeatedly and corrected Calculation again, design efficiency is low.As can be seen here, the many bases of present stage oblique roller rolling section design method In Conventional wisdom, designing loaded down with trivial details, efficiency is low, simultaneously the deformation behaviour of combination oblique roll process the most not yet in effect and metal flow feature, It is difficult to high accuracy, the production of high-performance oblique milling part.

Summary of the invention

It is an object of the invention to provide the thin geode type oblique roller rolling method for designing of a kind of high accuracy, it is possible not only to simplify Hole type design, improves design efficiency, it is also possible to make pass change preferably adapt to oblique roll process deformation behaviour and metal flow Feature, significantly improves forming accuracy and the degree of grain refinement of oblique milling formation of parts.

The technical solution adopted for the present invention to solve the technical problems is:

The thin geode type oblique roller rolling method for designing of a kind of high accuracy, comprises the steps:

S1, oblique milling rolled piece and bar size design:

S101, according to allowance and thermal expansion effects, calculate part maximum rolling size L_r,max；

S102, according to the expanding effect in forming process, determine bar diameter d；

S2, oblique roller rolling basic parameter design: based on existing process experiences data and relational expression, determine that roll is joined substantially Number, including roll fin starting altitude H_b, start width W_b, end of a period width W_o, roll nominal diameter D_m, base circle diameter (BCD) D_b, pass Profiled section spiral total length θ_f, pass finishing section spiral total length θ_s, fin end height H_o；

S3, oblique roller rolling fin height variation feature design: guarantee rolled piece can stably be nipped on the premise of rolling groove, base It is designed in coordinating metal material homogeneous deformation principle in the operation of rolling, shaped segment fin height variation feature is designed as power Refer to function curve version, be θ corresponding to helical groove length of run_xThe fin height H (θ of position_x) by comprising index E_H's Following power-exponent function formula determines,

Wherein, θ_bAnd θ_oIt is respectively fin to initiate and ultimate position threaded hole Type length of run value, [E_H]_m≤_iE_Hn＜ 1, [E_H]_minFor meeting formula Index E_HMinima；

S4, oblique roller rolling fin change width characteristic Design: based on be connected the axially extending principle that adapts of neck and set Meter, increases with the reduction of its external diameter owing to connecting the axially extending degree of neck, therefore fin change width characteristic Design is the most slowly to increase Add, roll the later stage and the most quickly increase, fin change width characteristic Design is become power-exponent function curvilinear motion form, any threaded hole Type length of run is θ_xThe fin width W (θ of position_x) determined by following formula,

Wherein, E_BFor the index of the power-exponent function of fin width, E_B>1。

By technique scheme, in step S101, for a certain size L of part_i, according to its allowance and high temperature Lower thermal expansion effects, its cold conditions oblique milling forming dimension L_i,c=L_i+ΔL_i, hot oblique milling forming dimension L_i,h=(L_i+ΔL_i) Q, right Maximum rolling size L answered_r,max=max (L_i,c, L_i,h), wherein, Δ L_i-correspondingly-sized L_iAllowance, Q-material is corresponding Thermal coefficient of expansion under rolling temperature.

By technique scheme, in step s 102, bar is determined according to the expanding effect in bar oblique milling forming process Diameter d, d=(1-k) L_r,max, wherein, the enlarging rate in k-bar roll forming, k is 3～4%, L_r,max-part maximum rolls Size.

By technique scheme, based on existing process experiences data, determine roll fin starting altitude H_b, start width W_b With end of a period width W_o, determine according to relationship below

Roll nominal diameter D_m=(5～7) d,

Base circle diameter (BCD) D_b=D_m-L_r,max,

Pass profiled section spiral total length θ_f=360 °～630 °,

Pass finishing section spiral total length θ_s=450 °～630 °,

Fin end of a period height H_o=D_m-d_c, wherein, d_c=(0.18～0.22) L_r,max。

By technique scheme, in step S3, index E_HThe determination of size comprises the following steps:

A), fin height increase speed degree can judge according to its change curve slope absolute value, power-exponent function curve Slope absolute value can be determined by the absolute value of its single order derived function, i.e.

$\left|H{\left({\mathrm{\θ}}_x\right)}^{\′}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\θ}}_b-{\mathrm{\θ}}_o)}^{E_H}}{({\mathrm{\θ}}_b-{\mathrm{\θ}}_x)}^{E_H-1},$

Work as θ_xFrom θ_bIt is reduced to θ_oTime, reasonable for the variation characteristic making fin height, i.e. first complete increasing speed faster The preliminary roll forming of rolled piece, after terminate rolling in the rolling later stage with the slower speed that increases, obtain E_H<1；

B), for ensureing that what rolled piece can be the most stable bites in rolling groove, fin height change rule should make roll Feed of every rotation m meet the bite condition of oblique milling pass, i.e. the maximum of its slope absolute value should meet

Wherein, μ-rolled piece and the coefficient of friction of roll part,

From the absolute value expression formula of the single order derived function of fin height power-exponent function, θ_xClose to fin original position θ_b Time, its slope absolute value is the biggest, works as θ_xFor θ_bTime, slope absolute value is infinitely great, for this, pass bite condition is limited to pass Length of run value is θ_b-20 arrive θ_oBetween, work as θ_xAt this during interval change, at θ_xFor (θ_b-20) maximum is obtained time, i.e.

${\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|}_{max}=\left|H{({\mathrm{\&theta;}}_b-20)}^{\&prime;}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o)}^{E_H}}{20}^{E_H-1},$

By above two formulas transformed after can obtain

${\left(\frac{20}{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o}\right)}^{E_H}\&le;\frac{{\mathrm{\&mu;}}^2{D_b}^2}{9(D_b+d)(H_o-H_b)}\&times;\frac{1}{E_H},$

The above formula left side is the exponential function that the truth of a matter is less than 1, and the right is inverse ratio array function, tries to achieve index E_HMinima [E_H]_min；

C), to sum up, E_HSpan is [E_H]_min≤E_H＜ 1.

The present invention, has the advantages that fin height and the change of width of appropriate design oblique milling pass of the present invention Rule, the flow deformation feature of metal material in the oblique milling forming process that is allowed to preferably to fit, thus improve in the operation of rolling and roll In the adaptability of part deformation state and pass and the operation of rolling, the coordination of deformation and uniformity, finally make part obtain more preferably Forming accuracy and degree of grain refinement.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:

Fig. 1 is the structural representation of screw groove diagonal rolling roll in the embodiment of the present invention；

Fig. 2 is the partial enlarged drawing in the embodiment of the present invention at roll fin；

Fig. 3 is the design diagram of oblique roller rolling fin height in the embodiment of the present invention；

Fig. 4 is the design diagram of oblique roller rolling fin width in the embodiment of the present invention.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, right The present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, not For limiting the present invention.

In the preferred embodiment, as Figure 1-Figure 4, the thin geode type oblique roller rolling design side of a kind of high accuracy Method, comprises the steps:

S1, oblique milling rolled piece and bar size design:

S101, because the product that oblique milling shapes typically requires and stays certain processing for follow-up machining and heat treatment step Surplus, the most also needs to consider material expansion at high temperature, therefore, imitates according to allowance and thermal expansion for hot-rolled product Should, calculate part maximum rolling size L_r,max, concrete, for a certain size L of part_i, according to its allowance and high temperature Lower thermal expansion effects, its cold conditions oblique milling forming dimension (its cold conditions size is for hot helical rolling) L_i,c=L_i+ΔL_i, hot oblique milling Forming dimension L_i,h=(L_i+ΔL_i) Q, corresponding maximum rolling size L_r,max=max (L_i,c, L_i,h), wherein, Δ L_i-corresponding chi Very little L_iAllowance, the thermal coefficient of expansion under Q-material correspondence rolling temperature；

S102, according to the expanding effect in forming process, determine bar diameter d, close according to value of calculation control selection again Standard round steel, concrete, determine bar diameter d, d=(1-k) L according to the expanding effect in bar oblique milling forming process_r,max, Wherein, the enlarging rate in k-bar roll forming, k usual for bearing steel is 3～4%, L_r,max-part maximum rolling size；

S2, oblique roller rolling basic parameter design: based on existing process experiences data and relational expression, determine that roll is joined substantially Number, including roll fin starting altitude H_b, start width W_b, end of a period width W_o, roll nominal diameter D_m, base circle diameter (BCD) D_b, pass Profiled section spiral total length θ_f, pass finishing section spiral total length θ_s, fin end height H_o, concrete, based on existing work Skill empirical data, determines roll fin starting altitude H_b, start width W_bWith end of a period width W_o, determine according to relationship below

Roll nominal diameter D_m=(5～7) d,

Base circle diameter (BCD) D_b=D_m-L_r,max,

Pass profiled section spiral total length θ_f=360 °～630 °,

Pass finishing section spiral total length θ_s=450 °～630 °,

Fin end of a period height H_o=D_m-d_c, wherein, d_c=(0.18～0.22) L_r,max；

S3 is as it is shown on figure 3, oblique roller rolling fin height variation feature designs: fin height in part oblique milling forming process The variation characteristic biting into shaping end of a period from pass directly determines metal flow and deformational behavior rolled piece roll form process, Therefore, being designed as of fin height variation feature is ensureing that rolled piece can stably be nipped on the premise of rolling groove, should beneficially assist Adjust the homogeneous deformation of metal material in the operation of rolling, improve roll forming goods forming accuracy and degree of grain refinement, i.e. base It is designed, based on above-mentioned thought, rational fin height change in coordinating metal material homogeneous deformation principle in the operation of rolling Gathering way of fin drafts should be designed as carrying out with rolling and be gradually reduced by feature, and i.e. fin height is before this with comparatively fast The speed that increases complete the preliminary roll forming of rolled piece, then terminate rolling, often at rolling stage with the slower speed that increases In the mathematical function curve seen, power-exponent function relation is relatively simple, and curvilinear motion feature can preferably meet above-mentioned fin height Variation characteristic, therefore shaped segment fin height variation feature can be designed as power-exponent function curvilinear motion form, corresponding to spiral shell Trepanning type length of run is θ_xThe fin height H (θ of position_x) by comprising index E_HFollowing power-exponent function formula determine,

Wherein, θ_bAnd θ_oIt is respectively fin to initiate and ultimate position threaded hole Type length of run value, [E_H]_m≤_iE_Hn＜ 1, [E_H]_minFor meeting formula Index E_HMinima；

Describe in the power-exponent function relation of fin height variation feature, index E_HSize decides fin height increases form And speed degree, to oblique milling forming technology important, index E_HBig I determined in terms of following two:

A), fin height increase speed degree can judge according to its change curve slope absolute value, foregoing description fin The power-exponent function slope of curve absolute value of height variation feature can be determined by the absolute value of its single order derived function, i.e.

$\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o)}^{E_H}}{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_x)}^{E_H-1},$

The power-exponent function slope of curve absolute value thus describing fin height change understands, index E_HDuring equal to 1, fin is high Degree change curve slope is constant, namely fin height is by traditional straight line rule change；Index E_HDuring more than 1, fin is high Degree is from helical groove original position (θ_b) arrive pass ultimate position (θ_o), i.e. θ_xFrom θ_bIt is reduced to θ_oTime, its slope absolute value be by Cumulative greatly；Work as E_HDuring less than 1, fin slope is to be gradually reduced, therefore, only when the index E of above-mentioned power-exponent function_HDuring less than 1, The raised feature of fin height just meets the Variation Features first quick and back slow of previous designs, say, that work as θ_xFrom θ_bIt is reduced to θ_o Time, reasonable for the variation characteristic making fin height, i.e. first with increase faster speed complete rolled piece preliminary roll forming, after The rolling later stage terminates rolling with the slower speed that increases, and obtains E_H<1；

B), for ensureing that what rolled piece can be the most stable bites in rolling groove, fin height change rule should make roll Feed of every rotation m meet the bite condition of oblique milling pass, i.e.

Wherein, μ is the coefficient of friction of rolled piece and roll part,

For making to realize normally nipping of rolled piece by the fin height of power-exponent function curve law change, only need its slope The maximum of absolute value meets following relational expression of nipping, i.e.

$360\&times;{\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|}_{max}\&le;2{\mathrm{\&mu;}}^2\frac{{D_b}^2}{D_b+d},$

From the absolute value expression formula of the single order derived function of fin height power-exponent function, θ_xClose to fin original position θ_b Time, its slope absolute value is the biggest, works as θ_xFor θ_bTime, slope absolute value is infinitely great, for this, pass bite condition is limited to pass Length of run value is θ_b-20 arrive θ_oBetween, work as θ_xAt this during interval change, at θ_xFor (θ_b-20) maximum is obtained time, i.e.

${\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|}_{max}=\left|H{({\mathrm{\&theta;}}_b-20)}^{\&prime;}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o)}^{E_H}}{20}^{E_H-1},$

By above two formulas transformed after can obtain

${\left(\frac{20}{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o}\right)}^{E_H}\&le;\frac{{\mathrm{\&mu;}}^2{D_b}^2}{9(D_b+d)(H_o-H_b)}\&times;\frac{1}{E_H},$

The above formula left side is the exponential function that the truth of a matter is less than 1, and the right is inverse ratio array function, can be by graphing method or by Matlab Try to achieve index E_HMinima [E_H]_min；

C), in summary, its index E of power-exponent function of fin height variation feature is described_HSpan is [E_H]_min≤E_H ＜ 1；

S4, as shown in Figure 4, oblique roller rolling fin change width characteristic Design: in part oblique milling forming process, connect with fin Touching and bear the connecting neck portion of radial compression, along with the increase of fin height, metal fills type towards the flowing of both sides die cavity, connects neck External diameter constantly reduces, and axially extending degree is gradually increased, for avoid to the full extent rolled piece in pass advancing slip or rear cunning and lead Cause to connect neck premature failure or rolled piece cannot normally rotate, the change of oblique roller rolling fin width should as far as possible with the axle being connected neck Adapt to extension, therefore, oblique roller rolling fin change width feature based on be connected the axially extending principle that adapts of neck and carry out Design, increases with the reduction of its external diameter owing to connecting the axially extending degree of neck, therefore is to make the change of fin width the most therewith Adapt, fin change width characteristic Design is the most quickly increased for being first slowly increased, roll the later stage, common in mathematical function Power-exponent function is when its index is more than 1, it is possible to achieve above-mentioned fin change width feature, to this end, by fin change width feature Being designed to power-exponent function curvilinear motion form, any helical groove length of run is θ_xThe fin width W (θ of position_x) true by following formula It is fixed,

Wherein, E_BFor the index of the power-exponent function of fin width, E_B> 1, can First to press fin height change exponent E_HValue reciprocal, connect neck length degree and fin width further according to closed type position Adaptedness finely tuned.

The present invention, when specifically applying, with reference to steel bearing balls standard size series, chooses the axle of a diameter of 28.575mm Holding steel ball is oblique milling product object, below by design and the reality heat of the GCr15 bearing steel ball oblique roller rolling pass with this size Oblique milling is tested, and discusses the reliability of part oblique roller rolling section design method of the present invention.

The present invention specifically includes following steps:

S1, oblique milling rolled piece and bar size design: according to aforementioned oblique milling rolled piece and the method for designing of bar size, for becoming Product diameter L₁For the GCr15 bearing steel ball of 28.575mm, allowance takes Δ L₁For 1.125mm, thermal coefficient of expansion takes 1.01, can To determine its cold conditions diameter dimension L_1,cFor 29.7mm, hot diameter dimension L_1,hFor 30mm, corresponding rolling is with bar diameter d then For 29mm；

S2, oblique roller rolling basic parameter design: according to the present invention aforementioned oblique roller rolling Parameters design, it may be determined that roll Roller nominal diameter D_mFor 180mm, roll base circle diameter (BCD) D_bFor 150mm, pass profiled section helix length θ_fIt is 630 °, pass essence Main plot section helix length θ_sIt is 630 °, fin starting altitude H_bWith width W_bIt is respectively 1.5mm and 2mm, fin end of a period height H_oWith Width W_oIt is respectively 13.6mm and 4.4mm；

S3, fin height variation feature design: according to fin height variation feature method for designing of the present invention, permissible The power-exponent function index determining height variation feature is 0.8, then its optional position fin height H (θ_x) it is:

$H\left({\mathrm{\&theta;}}_x\right)=H_b+(H_o-H_b){\left(\frac{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_x}{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o}\right)}^{E_H}=1.5+12.1\&times;{\left(\frac{1260-{\mathrm{\&theta;}}_x}{630}\right)}^{0.8};$

S4, fin change width characteristic Design: according to fin change width feature design method of the present invention, permissible The power-exponent function index determining change width feature is 1.2, then its optional position fin width W (θ_x) it is:

$W\left({\mathrm{\&theta;}}_x\right)=W_b+(W_o-W_b){\left(\frac{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_x}{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o}\right)}^{E_B}=2+2.4\&times;{\left(\frac{1260-{\mathrm{\&theta;}}_x}{630}\right)}^{1.2};$

S5, hot helical rolling shape: in order to oblique roller rolling section design method superiority of the present invention is described, respectively with by passing The roll of the design of system section design method and the roll of Roller Design method of the present invention design carry out bearing steel ball heat Oblique milling forming experiment, roll rotational speed 60r/min, the rolling temperature after the sensed heating of bar is 1150 DEG C, two rolls intersection cloth Putting inclination angle is 3 °, for ease of measuring the crystallite dimension after steel ball oblique milling shapes, enters the steel ball rolled from skew rolling mill immediately Water cooling.

Respectively to by tradition section design method and the method for the invention design, the steel ball of roll forming is become Shape size and crystallite dimension are measured.By slide gauge, the measurement result of steel ball size is shown that the method for the invention is rolled into The steel ball size of shape is stable at each location comparison of sphere, maintains 39.68～39.72mm, and presses traditional design method rolling Steel ball near connect neck position dimension less than normal, the minimum diameter recorded is 39.30mm, than design forming dimension 39.7mm is little 0.4mm.Choose at steel ball heart portion, two/Radius during ball rolling on radial compression direction and table Layer carries out crystallite dimension measurement, records and is followed successively by by the steel ball crystallite dimension of tradition section design method rolling: 44.2 μm, and 35.6 μm, 27.5 μm；And be followed successively by by the steel ball crystallite dimension measurement result of section design method roll forming of the present invention: 37.2 μm, 33.0 μm, 23.8 μm.Tested result from above-mentioned experiment, compare tradition section design method, by oblique milling of the present invention What section design method can be effectively improved oblique milling part fills type effect and crystallite dimension degree of refinement, preferably improves oblique milling Product shaping precision and degree of grain refinement.

It should be appreciated that for those of ordinary skills, can be improved according to the above description or be converted, And all these modifications and variations all should belong to the protection domain of claims of the present invention.

Claims (5)

1. a high accuracy thin geode type oblique roller rolling method for designing, it is characterised in that it comprises the steps:

S1, oblique milling rolled piece and bar size design:

S101, according to allowance and thermal expansion effects, calculate part maximum rolling size L_r,max；

S102, according to the expanding effect in forming process, determine bar diameter d；

S2, oblique roller rolling basic parameter design: based on existing process experiences data and relational expression, determine roll basic parameter, bag Include roll fin starting altitude H_b, start width W_b, end of a period width W_o, roll nominal diameter D_m, base circle diameter (BCD) D_b, pass formation zone Section spiral total length θ_f, pass finishing section spiral total length θ_s, fin end height H_o；

S3, oblique roller rolling fin height variation feature design: guarantee rolled piece can stably be nipped on the premise of rolling groove, based on association Adjust metal material homogeneous deformation principle in the operation of rolling to be designed, shaped segment fin height variation feature is designed as power and refers to letter Number curve version, is θ corresponding to helical groove length of run_xThe fin height H (θ of position_x) by comprising index E_HFollowing Power-exponent function formula determines,

Wherein, θ_bAnd θ_oIt is respectively fin to initiate and ultimate position helical groove Length of run value, [E_H]_min≤E_H＜ 1, [E_H]_minFor meeting formula's Index E_HMinima；

S4, oblique roller rolling fin change width characteristic Design: based on be connected the axially extending principle that adapts of neck and be designed, by Increase with the reduction of its external diameter in connecting the axially extending degree of neck, therefore fin change width characteristic Design is for being first slowly increased, rolling Later stage processed the most quickly increases, and fin change width characteristic Design becomes power-exponent function curvilinear motion form, any helical groove exhibition Open a length of θ_xThe fin width W (θ of position_x) determined by following formula,

Wherein, E_BFor the index of the power-exponent function of fin width, E_B>1。

Method the most according to claim 1, it is characterised in that in step S101, for a certain size L of part_i, root According to thermal expansion effects under its allowance and high temperature, its cold conditions oblique milling forming dimension L_i,c=L_i+ΔL_i, hot oblique milling forming dimension L_i,h=(L_i+ΔL_i) Q, corresponding maximum rolling size L_r,max=max (L_i,c, L_i,h), wherein, Δ L_i-correspondingly-sized L_iAdd Spare time measures, the thermal coefficient of expansion under Q-material correspondence rolling temperature.

Method the most according to claim 2, it is characterised in that in step s 102, according in bar oblique milling forming process Expanding effect determine bar diameter d, d=(1-k) L_r,max, wherein, the enlarging rate in k-bar roll forming, k is 3～4%, L_r,max-part maximum rolling size.

Method the most according to claim 3, it is characterised in that in step S2, based on existing process experiences data, determines and rolls Roller fin starting altitude H_b, start width W_bWith end of a period width W_o, determine according to relationship below

Roll nominal diameter D_m=(5～7) d,

Base circle diameter (BCD) D_b=D_m-L_r,max,

Pass profiled section spiral total length θ_f=360 °～630 °,

Pass finishing section spiral total length θ_s=450 °～630 °,

Fin end of a period height H_o=D_m-d_c, wherein, d_c=(0.18～0.22) L_r,max。

Method the most according to claim 1, it is characterised in that in step S3, index E_HThe determination of size includes following step Rapid:

A), fin height increase speed degree can judge according to its change curve slope absolute value, the power-exponent function slope of curve Absolute value can be determined by the absolute value of its single order derived function, i.e.

$\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o)}^{E_H}}{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_x)}^{E_H-1},$

Work as θ_xFrom θ_bIt is reduced to θ_oTime, reasonable for the variation characteristic making fin height, i.e. first complete rolled piece increasing speed faster Preliminary roll forming, after terminate rolling in the rolling later stage with the slower speed that increases, obtain E_H<1；

B), for ensureing that what rolled piece can be the most stable bites in rolling groove, fin height change rule should make the every of roll Turn amount of feeding m to meet the maximum of the bite condition of oblique milling pass, i.e. its slope absolute value and should meet

Wherein, μ-rolled piece and the coefficient of friction of roll part,

From the absolute value expression formula of the single order derived function of fin height power-exponent function, θ_xClose to fin original position θ_bTime, its Slope absolute value is the biggest, works as θ_xFor θ_bTime, slope absolute value is infinitely great, for this, pass bite condition is limited to pass and launches Length value is θ_b-20 arrive θ_oBetween, work as θ_xAt this during interval change, at θ_xFor (θ_b-20) maximum is obtained time, i.e.

${\left|H{\left({\mathrm{\&theta;}}_x\right)}^{\&prime;}\right|}_{max}=\left|H{({\mathrm{\&theta;}}_b-20)}^{\&prime;}\right|=E_H\frac{(H_o-H_b)}{{({\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o)}^{E_H}}{20}^{E_H-1},$

By above two formulas transformed after can obtain

${\left(\frac{20}{{\mathrm{\&theta;}}_b-{\mathrm{\&theta;}}_o}\right)}^{E_H}\&le;\frac{{\mathrm{\&mu;}}^2{D_b}^2}{9(D_b+d)(H_o-H_b)}\&times;\frac{1}{E_H},$

The above formula left side is the exponential function that the truth of a matter is less than 1, and the right is inverse ratio array function, tries to achieve index E_HMinima [E_H]_min；

C), to sum up, E_HSpan is [E_H]_min≤E_H＜ 1.