The manufacture method of pipe and apparatus for fixed diameter rolling
Technical field
The present invention relates to a kind of manufacture method and apparatus for fixed diameter rolling of pipe, this apparatus for fixed diameter rolling has a plurality of concave rolls of at least two rollers at each roll mill, the manufacture method of this pipe can suppress the generation and the expansion of the wrinkle that may take place at the inner surface of pipe effectively when by above-mentioned apparatus for fixed diameter rolling pipe being carried out fixed diameter rolling.
Background technology
Usually be processed in the operation of setting at external diameter, use apparatus for fixed diameter rolling such as sizing mill, stretch-reducing mill pipe.This apparatus for fixed diameter rolling is known to be had to have at each roll mill and depresses the 3 roll-type apparatus for fixed diameter rolling that the angular separation is 3 concave rolls (following suitably be called " roll ") of 120 °.In addition, it is also known for to have and depress the 4 roll-type apparatus for fixed diameter rolling that the angular separation is 4 concave rolls of 90 ° at each roll mill.It is also known for the 2 roll-type apparatus for fixed diameter rolling that have two relative concave rolls at each roll mill.
, recently, the necessity of the environment of preserving our planet improves constantly, and also requires further to realize energy-saving effect for the vehicle body of automobile.For this purpose, the requirement of body lightening improves, and for this reason, is just attempting the driving shaft in the automobile component is changed over hollow unit (pipe) by solid component.
The automobile driving shaft is the important safety assurance parts that the transmission of torque of engine rotation axle arrived tire, need guarantee enough fatigue resistances.Therefore, with effective when making automobile and using driving shaft, need do one's utmost to suppress to make concavo-convex (to call " wrinkle " in the following text) of the accordion-like of the pipe internal surface that the fatigue strength of pipe significantly descends.
And, often take place in these wrinkle operation in the manufacturing process of pipe, that external diameter of pipe is processed as setting.Its reason can be thought not use the instrument that pipe internal surface is retrained owing to apparatus for fixed diameter rolling when pipe is carried out fixed diameter rolling, so, produce wrinkle at pipe internal surface easily.
Summary of the invention
The present invention makes in order to solve such prior art problems, it is based on the newfound opinion of present inventor, promptly, the reduction ratio to whole pipe (external diameter degree of finish) of discovery till from the entrance side of apparatus for fixed diameter rolling with a plurality of roll mills to outlet side produces very big influence to the generation and the expansion of the wrinkle of the pipe in the fixed diameter rolling operation.
Specifically, as shown in Figure 5,, produce wrinkle and expansion (it is big that the degree of depth of wrinkle becomes) at pipe internal surface along with the increase of apparatus for fixed diameter rolling to the external diameter degree of finish of pipe.The special discovery is that the boundary expands rapidly with the point of external diameter degree of finish 50%.In addition, be Di if set the external diameter of pipe of footpath rolling device entrance side, the external diameter of pipe of apparatus for fixed diameter rolling outlet side (processing diameter) be D, then the external diameter degree of finish value that following formula (2) defines of serving as reasons.
The external diameter degree of finish=(Di-D)/Di * 100 (%) ... (2)
It can also be seen that from Fig. 5, at the external diameter degree of finish more than or equal to about 50% o'clock, in the suitable position of edge part of the pipe of drawing with " ● " (in any roll mill, be position by the rolling pipe of the edge part of roll, when the apparatus for fixed diameter rolling with 3 roll-types is rolled, circumferentially totally 6 positions along pipe), the wrinkle concentrated area takes place and expansion.
Take place in the wrinkle concentrated area, the suitable position of edge part of this pipe and the reason of expansion can be thought, because the roll Pass profile be an ellipse, so it is more much bigger than the compression stress that other parts put on pipe to put on the compression stress of pipe from the edge part of roll.
According to above opinion,, can consider to limit the upper limit (for example making the external diameter degree of finish) of external diameter degree of finish less than 50% as the method for generation that suppresses wrinkle effectively and expansion.
Yet the method for the upper limit of restriction external diameter degree of finish when making multiple pipe by an apparatus for fixed diameter rolling, need correspondingly be prepared the pipe of multiple external diameter with it.That is the problem that the productivity ratio variation, occurs.
Therefore, wish to find such method, do not limit the upper limit of external diameter degree of finish,, also can suppress the generation and the expansion of wrinkle effectively even promptly the external diameter degree of finish is more than or equal to 50%.
Therefore, inventor of the present invention has further carried out conscientious discussion, found that, the interior surface curvature radius of the suitable position of edge part of pipe, the mean inner radius of pipe (mean value of minor axis and major diameter), and the degree of depth of wrinkle between have certain relation.
More particularly, when using the apparatus for fixed diameter rolling that constitutes by a plurality of roll mills that pipe is carried out fixed diameter rolling, if be rolled under at the mean value of all roll mills more than or equal to 0.55 condition at the ratio of the radius of curvature of the inner surface of the suitable position of edge part of pipe and mean inner radius, even then the external diameter degree of finish is more than or equal to 50%, also can suppress to betide the generation and the expansion of the wrinkle of pipe internal surface effectively, wherein this apparatus for fixed diameter rolling has a plurality of concave rolls at each roll mill.In addition, " the interior surface curvature radius of the suitable position of edge part of pipe and the mean value of the ratio of mean inner radius at all roll mills " be meant, the value after all roll mills are with the ratio equalization of the interior surface curvature radius of the suitable position of edge part of the pipe of each roll mill outlet side and mean inner radius.
Inventor of the present invention is according to above-mentioned opinion, promptly, take place in the wrinkle concentrated area, the suitable position of edge part of pipe and expansion is because the section of pass of concave roll for oval, conscientiously discussed have more approaching just round section of pass and as described above the ratio of interior surface curvature radius and the mean inner radius of the suitable position of edge part of pipe in the mean value of all roll mills condition more than or equal to 0.55 concave roll.The result, inventor of the present invention finds, the opposed edges portion cutting-up line of mutually adjacent concave roll in each roll mill respectively, stipulate correspondingly that with the ratio of external diameter the minimum of a value of angle in all roll mills of this tangent line gets final product, and finished the present invention thus with the wall thickness of the pipe of apparatus for fixed diameter rolling outlet side.
Promptly, the invention provides a kind of manufacture method of pipe,, be used to make the pipe that is used for automobile usefulness driving shaft, the manufacture method of this pipe comprises apparatus for fixed diameter rolling that use is made of a plurality of roll mills pipe is carried out the operation of fixed diameter rolling, and each roll mill of these a plurality of roll mills has a plurality of concave rolls; Use following concave roll, promptly, the section of pass of this concave roll has single circular arc, and satisfy following condition: the opposed edges portion cutting-up line of mutually adjacent concave roll in above-mentioned each roll mill respectively, if the minimum of a value of the angle of this tangent line in all roll mills is β (deg), the external diameter of the pipe of above-mentioned apparatus for fixed diameter rolling outlet side is D (mm), when the wall thickness of the pipe of above-mentioned apparatus for fixed diameter rolling outlet side is t (mm), above-mentioned angle beta satisfies with following formula (1), and, when the external diameter of pipe of establishing above-mentioned apparatus for fixed diameter rolling entrance side is Di (mm), to be set at more than 50% by the external diameter degree of finish of following formula (2) definition
β≥1.13×10×Ln(t/D×100)+1.37×10
2...(1)
The external diameter degree of finish=(Di-D)/Di * 100 (%) ... (2).
According to the present invention, satisfy the concave roll of above-mentioned formula (1) by use angle β, even the external diameter degree of finish of pipe more than or equal to 50%, also makes the compression stress of the suitable position of edge part that puts on pipe relax (dispersion).As a result, the ratio of radius of curvature and mean inner radius of inner surface of the suitable position of edge part that can make pipe more than or equal to 0.55, can suppress to betide the generation and the expansion of wrinkle of the inner surface of pipe at the mean value of all roll mills effectively.
In addition, the present invention also provides a kind of apparatus for fixed diameter rolling, and this apparatus for fixed diameter rolling is made of a plurality of roll mills, carries out fixed diameter rolling to being used for automobile with the pipe of driving shaft, and each roll mill of these a plurality of roll mills has a plurality of concave rolls; Wherein, has following concave roll, promptly, the section of pass of this concave roll has single circular arc, and satisfy following condition: the opposed edges portion cutting-up line of mutually adjacent concave roll in above-mentioned each roll mill respectively, if the minimum of a value of the angle of this tangent line in all roll mills is β (deg), the external diameter of the pipe of above-mentioned apparatus for fixed diameter rolling outlet side is D (mm), when the wall thickness of the pipe of above-mentioned apparatus for fixed diameter rolling outlet side is t (mm), above-mentioned angle beta satisfies with following formula (1), and, when the external diameter of pipe of establishing above-mentioned apparatus for fixed diameter rolling entrance side is Di (mm), to be set at more than 50% by the external diameter degree of finish of following formula (2) definition
β≥1.13×10×Ln(t/D×100)+1.37×10
2...(1)
The external diameter degree of finish=(Di-D)/Di * 100 (%) ... (2).
According to the manufacture method and the apparatus for fixed diameter rolling of pipe of the present invention, when pipe being carried out fixed diameter rolling, can suppress to betide the generation and the expansion of the wrinkle of pipe internal surface effectively by apparatus for fixed diameter rolling.
Description of drawings
Fig. 1 is the figure of 3 roll-type apparatus for fixed diameter rolling of manufacture method that the pipe that is suitable for an embodiment of the present invention roughly is shown.
Fig. 2 is the external diameter degree of finish that is illustrated in pipe more than or equal to the ratio of 50% o'clock, the interior surface curvature radius of the suitable position of edge part of pipe and mean inner radius at the mean value of all roll mills and the figure of the relation of the degree of depth of the wrinkle that result from pipe internal surface.
Fig. 3 is the key diagram that is used to illustrate the angle of the tangent line that the edge part at concave roll marks.
Fig. 4 be the minimum of a value β of angle beta o shown in Figure 3 in all roll mills is shown, at the ratio of the interior surface curvature radius of the suitable position of edge part of the ratio of the wall thickness t of the pipe of apparatus for fixed diameter rolling outlet side and outer diameter D and pipe and mean inner radius figure in the relation of the mean value of all roll mills.
Fig. 5 illustrates the external diameter degree of finish of apparatus for fixed diameter rolling and the figure of the relation of the depth capacity of the wrinkle that result from rolling pipe internal surface.
Fig. 6 is the figure of the section of pass of concave roll that present embodiment roughly is shown.
Fig. 7 (a) and (b), (c) are the figure of the section of pass of concave roll that other embodiment of the present invention is shown partly.
The specific embodiment
Below suitably with reference to the description of drawings one embodiment of the present invention.
Fig. 1 is the figure of 3 roll-type apparatus for fixed diameter rolling of manufacture method that the pipe that is suitable for an embodiment of the present invention roughly is shown.As shown in Figure 1, at the apparatus for fixed diameter rolling of present embodiment (in the present embodiment, carry out the rolling stretch-reducing mill of hot size) in 1, at a plurality of (N, in the present embodiment, N=17) being respectively equipped with the angle of depressing direction on roll mill #1~#N is 3 concave rolls 10 of 120 °, and roll 10 depresses the direction 60 ° of ground alternate configurations that stagger between adjacent roll mill.In the pass that forms by each roll of each roll mill, pass pipe P as rolling object, carry out fixed diameter rolling at the outlet side of final roll mill #N and make its external diameter become predetermined setting.In addition, be the external diameter of Di, outlet side when being D if set the external diameter of the pipe P of footpath rolling device 1 entrance side, then set each roll mill roll 10 size and the position is set to become external diameter degree of finish by following formula (2) definition.
The external diameter degree of finish=(Di-D)/Di * 100 (%) ... (2)
Fig. 2 is the result's of expression the present inventor investigation curve map, be illustrated in the external diameter degree of finish more than or equal to 50% o'clock, the interior surface curvature radius of the suitable position of edge part of pipe P and the relation of the mean value α of ratio in all roll mill #1~#N of mean inner radius with the degree of depth of the wrinkle that result from pipe P inner surface.More particularly, curve map among Fig. 2 is illustrated on one side the condition of the section of pass of the concave roll 10 of being located at each roll mill is carried out multiple change, on one side the relation of the mean value α of ratio in all roll mill #1~#N and the degree of depth of the wrinkle that result from pipe P inner surface of the interior surface curvature radius of the suitable position of edge part of pipe P when the carbon steel tubing fixed diameter rolling of external diameter 100mm, wall thickness 11mm become external diameter 40mm, wall thickness 9.6mm and mean inner radius.
Wherein, mean value α obtains like this, promptly, measure the interior surface curvature radius and the mean inner radius of the suitable position of edge part of pipe P at each roll mill outlet side by using 3 d shape testing device (the accurate society in Tokyo makes), will be average to the ratio between two that each roll mill outlet side calculates with all roll mill numbers according to this measured value, the value that obtains after average is this mean value α.The serve as reasons value of following step (a)~(c) obtain of mean value α.
(a) at each the roll mill outlet side interior surface curvature radius of measuring the suitable position of edge part of managing P and mean inner radius, that become the investigation object, end the rolling of pipe P and (take off pipe P from apparatus for fixed diameter rolling 1, or do not carry at the back level roll mill of this roll mill not rollingly), the part of this pipe P is cut as sample.
(b) for the sample that cuts out, use the 3 d shape testing device to measure the interior surface curvature radius and the mean inner radius of the suitable position of edge part, calculate ratio between two.
More particularly, at first the inner surface configuration data (constituting the coordinate data of the each several part of inner surface) of the section of the pipe P of the initial use of basis 3 d shape testing device mensuration calculate the position of centre of gravity of managing the P inner surface.Then, use is in the coordinate at inner surface position (promptly being positioned at the inner surface position of pipe P in the centre position, gap of the opposed edges portion that is equivalent to adjacent concave roll) of the pipe P that is equivalent to concave roll flange part position and the center of gravity revolution that goes out around aforementioned calculation from above-mentioned position ± 5 ° the coordinate at each inner surface position of pipe P of position approximately, calculate radius of a circle, with the interior surface curvature radius of this radius that calculates as the suitable position of edge part by these 3 positions.Then, establishing above-mentioned center of gravity is inside radius with the distance that constitutes each position of managing the P inner surface, will be along managing the circumferential inside radius mean value of P as mean inner radius.As described above, calculate the interior surface curvature radius and the mean inner radius of the suitable position of edge part respectively, calculate ratio between two.
(c) outlet side at all roll mills carries out above-mentioned (a) and step (b) repeatedly, and measured value (the interior surface curvature radius of the suitable position of edge part and the ratio of the mean inner radius) equalization with all roll mills calculates α.
Below with the above step that illustrates of concrete example explanation.For example, data point a shown in Figure 2 (α=0.42, the wrinkle degree of depth=0.135mm), some b (α=0.57, the wrinkle degree of depth=0.05), some c (α=0.92, the α of the wrinkle degree of depth=0.04mm) is such as shown in the following Table 1 respectively, is the value that the interior surface curvature radius r/averaging of mean inner radius d obtains of the suitable position of edge part that will calculate each roll mill outlet side with all roll mill numbers.
[table 1]
In addition, the wrinkle degree of depth shown in Figure 2 is meant the maximum of the wrinkle degree of depth of the pipe P that measures at apparatus for fixed diameter rolling 1 outlet side, for cutting out, section is carried out the value that microscopic observation is measured as sample by the part with the pipe P after rolling.
Can learn that from Fig. 2 α is the boundary with about 0.55, as littler than it, then the degree of depth of wrinkle increases rapidly.Therefore, as on the contrary α being made as more than or equal to 0.55, then can suppress effectively may be in the generation and the expansion of the wrinkle of managing the generation of P inner surface.
Therefore, in the apparatus for fixed diameter rolling 1 of present embodiment, configuration, is specified the reason of the condition of setting such roll 10 and imposes a condition more than or equal to the roll of such condition of 0.55 below 10. by the α of the rolling pipe P of apparatus for fixed diameter rolling 1.
At first, as shown in Figure 3, edge part Ea cutting-up line (tangent line of the section of pass near the edge part Ea) La at the roll 10a that each roll mill has, in the edge part of the roll 10b adjacent with roll 10a, with the edge part Ea opposed edges Eb of portion cutting-up line (tangent line of edge part Eb section of pass nearby) Lb, calculate the angle β o of two tangent line La, Lb.In addition, as shown in Figure 6, it is the circular arc of radius centered R that the section of pass of each roll 10 of present embodiment has with O ', (roll line center) O of this center O ' from the pass center is toward foreign side's (direction of leaving from the bottom land C of roll 10) skew (side-play amount S), and this circular arc be and the direct shape of intersecting of flange side wall surface F of roll 10.And the edge part E of roll 10 (being the end of section of pass PR) is equivalent to the end of the circular arc of above-mentioned radius R.Above-mentioned angle beta o calculates (the angle beta o at 3 positions that each roll mill is calculated all is identical value) according to this section of pass with method of geometry.
Then, if angle beta o is β (deg) in the minimum of a value of all roll mill #1~#N, at the external diameter (target external diameter) of the pipe P of apparatus for fixed diameter rolling 1 outlet side for D (mm), at the wall thickness (target wall thickness) of the pipe P of apparatus for fixed diameter rolling 1 outlet side during for t (mm), according to inventor's of the present invention investigation as can be known, β, t/D, and α be as shown in Figure 4 relation.At this, the transverse axis of Fig. 4 is represented t/D (%), the longitudinal axis is represented β (deg), the α of the pipe P that the data representation of drawing with " zero " is rolling is 0.55 data, the α of the pipe P that the data representation of drawing with " ● " is rolling is than 0.55 big data, and the α of the pipe P that the data representation of drawing with " * " is rolling is less than 0.55 data.
Be described more specifically, for example, the data point A shown in Figure 4 (data that t/D=24.0%, β=173deg) obtain when according to condition shown in the following table 2 the carbon steel tubing fixed diameter rolling of external diameter 100mm, wall thickness 11mm being become external diameter 40mm, wall thickness 9.6mm.That is, under condition shown in the table 2, angle beta o is 173deg at the minimum of a value β of all roll mill #1~#17, at the t/D=24.0% of apparatus for fixed diameter rolling 1 outlet side (being #17 roll mill outlet side), so be depicted as coordinate shown in Figure 4.
[table 2]
Roll mill |
Outlet side outer diameter D (mm) |
Outlet side wall thickness t (mm) |
βo(deg) |
External diameter degree of finish (%) at single roll mill |
t/D(%) |
#1 |
97.0 |
10.9 |
173 |
3 |
112 |
#2 |
91.2 |
10.8 |
173 |
6 |
118 |
#3 |
85.7 |
10.7 |
173 |
6 |
12.5 |
#4 |
80.6 |
10.6 |
173 |
6 |
13.2 |
#5 |
75.7 |
10.5 |
173 |
6 |
13.9 |
#6 |
71.2 |
10.4 |
173 |
6 |
14.6 |
#7 |
66.9 |
10.3 |
173 |
6 |
15.4 |
#8 |
62.9 |
10.2 |
173 |
6 |
16.2 |
#9 |
59.1 |
10.1 |
173 |
6 |
17.1 |
#10 |
55.6 |
10.0 |
173 |
6 |
18.0 |
#11 |
52.2 |
9.9 |
173 |
6 |
18.9 |
#12 |
49.1 |
9.8 |
173 |
6 |
20.0 |
#13 |
46.2 |
9.7 |
173 |
6 |
21.0 |
#14 |
43.4 |
9.6 |
173 |
6 |
22.1 |
#15 |
41.2 |
9.6 |
178 |
5 |
23.3 |
#16 |
40.4 |
9.6 |
178 |
2 |
23.8 |
#17 |
40.0 |
9.6 |
180 |
1 |
24.0 |
Can learn from Fig. 4, make α, as long as β is set at more than or equal to setting with respect to each t/D more than or equal to 0.55.Therefore, in the present embodiment, be after the approximate α of function (natural logrithm function) of variable is 0.55 o'clock the value of β about each t/D, in order to t/D, set the section of pass of roll 10, so that β becomes the value more than or equal to this approximate function.More particularly, for making angle beta satisfy the section of pass that following formula (1) is set roll 10.
β≥1.13×10×Ln(t/D×100)+1.37×10
2...(1)
If use the roll 10 be set as described above to be rolled, then as described above, the α that can make pipe P is more than or equal to 0.55, so, can suppress to betide the generation and the expansion of the wrinkle of pipe P inner surface effectively.
In addition, with reference to Fig. 6 as mentioned above, the section of pass PR of each roll 10 of present embodiment has the single circular arc of radius R, and the edge part E of roll 10 (being the end of section of pass PR) is equivalent to the end of the circular arc of above-mentioned radius R.But the section of pass of each roll 10 of the present invention is not limited thereto, and also can adopt the roll with various section of pass as shown in Figure 7.Fig. 7 illustrates itself and the figure at the regional corresponding position that is surrounded by dotted line of Fig. 6 for the section of pass to the concave roll of other embodiment of the present invention.Shown in Fig. 7 (a), section of pass PR as each roll 10 of the present invention, also can use the shape that is constituted, directly intersected with flange side wall surface F by the different a plurality of circular arcs of radius, the edge part E of roll 10 in this case is equivalent to be positioned at the end of the circular arc (radius R n) of flange side.In addition, also can adopt between the flange side wall surface F of section of pass PR that constitutes by single circular arc or a plurality of circular arc and roll 10 shape (Fig. 7 (b)) that the what is called " yielding portion (escape) " that is made of the circular arc (radius r) of side's (towards the pass center) convex inwardly is set, or be provided with the shape (Fig. 7 (c)) of " the yielding portion " that constitute by straight line.The edge part E of the roll 10 under these situations is equivalent to constitute the end (being positioned at the end of the circular arc of flange side) of the circular arc of section of pass PR.
In addition, in the present embodiment, be that example is illustrated with 3 roll-type apparatus for fixed diameter rolling, but the invention is not restricted to this that what also can similarly be applicable to forms such as 4 roll-types or 2 roll-types has the apparatus for fixed diameter rolling of a plurality of concave rolls at each roll mill.