The roll spacings milling method such as helical tapered roll of large-sized aluminium alloy ultra fine grained steel bar
Technical field
The present invention relates to technical fields of mechanical processing, and in particular to the helical tapered roll of large-sized aluminium alloy ultra fine grained steel bar
Equal roll spacings milling method.
Background technique
Its equivalent strain usually should be greater than 6 when preparing nanometer materials, and traditional plastic processing method is difficult to accomplish, using super
Large plastometric set (Severe Plastic Deformation, SPD) can be realized.Modern SPD starts from Bridgemen proposition
Big pressure and shear-deformable combination forming mode, fast development start from mid-term former Soviet Union the 1970s and western countries,
Segal has developed Equal-channel Angular Pressing technology (Equal-Channel Angular Pressing, ECAP), and Valiev passes through
The change of grain structure proposes high performance huge possibility, indicates the arrival in the microstructure epoch of SPD research.Nearly more than 10 year
Come, thousands of research achievements are published.
It is universally recognized after 2006 to be defined about SPD: block being made to generate super large strain but unobvious change block geometry
The metal forming process of the grain refining effect of high-angle boundary is presented in size, can obtain crystallite dimension (100- in the micron-scale
1000nm) with nanoscale (less than 100nm), a nanometer SPD(abbreviation nanoSPD all can be described as).Since nanoSPD material has greatly
The wide-angle Non-equilibrium Grain Boundary tissue containing high density dislocation and high internal stress is measured, so that material shows to be different from traditional coarse-grain material
The mechanical behavior and deformation mechanism of material.
Current existing processing technology scheme: SPD typical case's forming technique, typical SPD method have high pressure torsion (High
Pressure Torsion, HPT), equal channel angular extrusion deformation (equal channel angular press-ing, ECAP),
Accumulation pack rolling method (Accumulative Roll Bonding, ARB), torsion squeeze (Twist Extrusion, TE) and multidirectional
It forges (Multi-Directional Forging, MDF).
Wherein, (1) high pressure torsion deforms: the primary sample (block or powder) being placed in support slot applies the pressure of several GPa
The characteristics of power, and two anvils above and below relative rotation make sample that intensive shear deformation occur and refine crystal grain, high pressure torsion is workpiece
For plate-like, size is smaller, and diameter is generally 10-20 mm, with a thickness of 0.2-0.5 mm.
(2) miter angle extruding deforming: by the cross-section channel of two intersection certain angles in mold, by material by one end
To the other end squeeze out, the change in material movement direction is allowed to by bending angle to generate pure shear shear deformation, may be repeated this at
Type process, shear strain amount increase with rolling pass.
(3) accumulate pack rolling method: by stacking double-deck after original plate surface treated, after heating roller welding together, then from
Centre cut off send back to surface treatment after carry out next roller welding circulation again, for guarantee rolling after plate can be welded together, per pass
Drafts must not be lower than 50%, but need strong shear stress condition in ARB process, lubricant cannot be used, this is to rolling
The service life of roller is unfavorable.
(4) torsion squeezes: Beygelzime etc. proposes the technique.The method is also by shear-deformable refinement crystal grain
Column blank is pressed through torsion mould by forming technique, and similar with HPT, there are deformation problem of non-uniform, grain refinement effect is low
In ECAP and HPT.
(5) multiway forging: the technique passes through multiple orthogonal change open die forging direction, obtains large deformation.The crystalline substance of such deformation
Grain thinning effect will be significantly lower than ECAP and HPT.
Another existing processing technology scheme: deriving method, SPD new process emerges one after another in recent years, and basic forming is former
Same above method is managed, many ECAP molding new technologies have been derived, these methods try hard to simplify tool design, reduce energy consumption, improve
Lumber recovery, lifting workpieces size, upgrading the degree of automation etc., wherein include:
(1) ECAP deriving method: bending alignment (RCS) repeatedly, blank is placed between Bending Mould, under upper mold
It moves, blank is bent over, and becomes wavy;It is then straightened with 2 pieces of plates, then carries out bending, by constantly repeating, unknown
Enough deformations, refiner material tissue are accumulated in the case where aobvious change billet size.
(2) circulation closed die forging (CCDF), mold are vertically moved in the cavity by the lower die of some section cavity and one
Same cross-sectional formed punch composition.The sample of sufficient lubrication with graphitic lubricant is put into lower die, certain temperature is heated to
Degree.Workpiece is pressed into lower die by formed punch, after taking-up, is rotated by 90 ° in the same direction around Z axis, lower die deformation is reinserted.This
Sample, workpiece are rotated by 90 ° between continuous channel around Z axis.In this way, it is subjected to 1,3 and 5 second compression respectively.
(3) reciprocating extrusion (CEC), mold are made of two die cavitys, a compression strap and the formed punch being placed in two die cavitys.
Two die cavity sectional areas are equal, on same axis, pass through intermediate compression band connection.In extrusion process, sample is in formed punch
Under the action of, compression strap is reached, at this point, sample will be deformed by forward extrusion, formed punch of the workpiece after extruding in another die cavity
Under effect, Upsetting occurs.Then, another side formed punch is reversely pushed back workpiece by the above process, completes an extrusion cycle.
Above procedure is repeated, until obtaining desired strain.
(4) plate continuous confined strip shearing, device using upper die and lower die and lower roll constitute two cross-sectional areas have it is a small amount of poor
Different cross one another channel.Plate is sent in die cavity, strong plastic deformation occurs in die cavity corner for plate, then from
The die cavity other side squeezes out.Groove is processed in feeding roller surface to be used to increase frictional force, due to deforming the transversal of front and back material
The characteristics of area remains unchanged can carry out the plastic deformation of multi-pass to plate repeatedly in same mold.
(5) ellipse spiral wait channel pressings method (ECEA), blank is under the action of extruding force, by round bar after upsetting pull
(circle-elliptic transformation), torsion (oval cross section torsion) and reversed upsetting pull (ellipse-circle transformation) process become round bar again.Metal
Plastic Flow, and accumulation strain are mainly generated on cross section.Round and elliptical particularity, type is utilized in mold shape
Wedge angle region is not present in chamber, keeps metal readily flowed.Realize the combination of one-time process process various deformation mode.
(6) continuous angle of friction squeezes (CFAE), and driven roller rotation simultaneously applies pressure P against its supporting element to workpiece.It is driving
First squeezing passage is formed between dynamic roller and workpiece support, second channel is the short slot in fixing mould component.Sheet
Workpiece is by one to eight processing, and up to 5.3, sheet material orientation remains constant for maximum equivalent logarithmic strain.
(7) a kind of HPT deriving method, suitable for the high pressure torsion (HPTT) of pipe, pipe is located in rigid disk, and mandrel is put into pipe
In, it is compressed under its elastic stage with compressor.It due to being compressed axially for mandrel, is radially expanded, expands by pipe and circle
The limitation of disk forms very big hydrostatic stress in pipe, generates biggish frictional force in the two sides of pipe.Mandrel is being kept to fix
In the case of, the deformation of pipe is realized by external torque rotating disk.In twist process, deformation pattern is partial cut, shear surface
Normal direction is the radial direction of pipe, and shear direction is parallel to circumferencial direction.
(8) a kind of TE deriving method, superelevation reverse (STS), make the region than other two by local heating and cooling
Part deformation resistance makes the torsional strain region (TS) localize.While generating the area TS, bar is moved along longitudinal axis,
Therefore super large plastic strain is continuously generated on entire bar.This new process STS includes the other parts generation office relative to bar
The bar of the movement of portion's soft zone and region along longitudinal direction.An important feature of STS is cross sectional dimensions holding in strain of bar
It is constant.
Aluminum alloy materials have more excellent characteristic than other non-ferrous metals, steel, plastics and timber etc., if density is small,
About 2.7g/cm3, almost it is the 1/3 of copper or steel;Preferable corrosion resistance;Good electrical and thermal conductivity performance;Forming easy to process
(plasticity good toughness);Good mechanical property etc..It is relatively fewer for the patent report of aluminium alloy Ultra-fine Grained technique both at home and abroad.It breathes out
Your shore polytechnical university Zhang Kai's cutting edge of a knife or a sword et al. is referred to a kind of preparation side of ultrafine grained Ni-Al alloy in patent [101857925 A of CN]
Method, wherein referring to the technological parameters such as preparation and heating temperature, heating rate, the application load of nickel alumin(i)um alloy powder.Although passing through
The average grain size that the technique obtains is 400nm, but in process program ball mill frequency of use it is excessive and use time mistake
It is long, and cause ultrafine grained Ni-Al alloy constant and finished size to be restricted using 1300 DEG C of high temperature furnaces, it is difficult to realization amount
It produces.Jiangsu University Liu expires equality people and is referred in patent [CN105331858 A] using the preparation of Equal-channel Angular Pressing method
The method of Ultra-fine Grained high-strength/tenacity aluminum alloy, although the background introduction of the method this patent is, it has been proposed that the corner by multi-pass squeezes
Pressure and solution treatment obtain 190 ~ 260nm Ultra-fine Grained, but finished size is smaller, be 20 × 20 × 100mm ~ 100 × 100 ×
350mm, it is difficult to meet technical grade demand.Liu Chongyu of Guilin University of Technology etc. is referred in patent [CN107058829 A]
A kind of preparation method of super fine crystal material.The method mainly makes to generate Ultra-fine Grained in the aluminium alloy of element containing scandium.Although what is obtained is flat
Equal crystallite dimension is 500nm, but the maximum tensile strength of the alloy only reaches 390 ~ 460MPa, is closed with other trade mark Ultra-fine Grained aluminium
There is also larger gaps for the tensile strength of gold.Central South University Xiao Daihong et al. is referred to one kind at patent [CN101876041 A]
The preparation method of the ultra-fine heat-resisting aluminium alloy of Al-Cu-Mg-Ag system.The preparation method of this patent be first with extrusion ratio be 8 ~ 15 into
Row hot extrusion, then in 350 ~ 430 DEG C of isometrical angle hot extrusions of progress multi-pass, obtained crystallite dimension is in 600nm ~ 2000nm model
In enclosing, but extrusion ratio be 8 ~ 15 extrusion process and multi-pass Equal Channel Angular Pressing to mould strength, die wear and product size
Etc. limitation it is larger, it is difficult to carry out volume production in the industrial production.And the degree of refinement of aluminium alloy crystal grain is lower in the patent.
For the paper of aluminium alloy Ultra-fine Grained technique report, Equal Channel Angular Pressing is used mostly, the modes such as ball milling heating extruding are to aluminium
Alloy is deformed, but related alloy size is smaller, it is difficult to generate industrialized application value.
Known to comprehensive analysis: the aluminium alloy fine grain technique referred in existing patent or paper mostly uses aluminium alloy cast ingot
Ball milling repeatedly, the technique that then method of hot extrusion or use multi-pass hot extrusion and Equal Channel Angular Pressing combine.But these are specially
Ultra-fine grained aluminium alloy geometric dimension obtained in benefit is smaller, can not temporarily be generalized to aerospace field.
Summary of the invention
The purpose of the present invention is to provide the isometric helix milling methods of large-sized aluminium alloy ultra fine grained steel bar, on solving
State that the deformed area proposed in background technique is smaller, penetrability is poor, size and the problems such as degree of refinement is limited, low efficiency.
The roll spacings milling methods such as the helical tapered roll of large-sized aluminium alloy ultra fine grained steel bar of the present invention, comprising the following steps:
S1: selection diameter dimension D is 40-200mm, and length is the aluminum alloy blank of 300-5000mm;
S2: above-mentioned aluminum alloy blank being placed in heating furnace and is heated to 380-450 DEG C, heating time are as follows: aluminium alloy alloy
Blank diameter D × (0.6 ~ 0.8) min;
S3: the aluminum alloy blank after heating is transported in skew rolling mill deflector chute from heating furnace, transhipment time 5-20s;
S4: carrying out feeding in the deflector chute of skew rolling mill, and aluminum alloy blank is sent between skew rolling mill entrance and exit
Deformed area, aluminum alloy blank is moved in deformed area inside spin to be terminated up to deforming, and obtains the rods and bars of aluminium alloy that diameter is Dm, wherein
M is rolling number;
S5: repeating above-mentioned S2-S4 step, and it is integrally ultra-fine to obtain aluminium alloy to aluminum alloy blank 2-14 screw rolling of progress
Crystal bar material;
The skew rolling mill is two-roller skew-rolling machine, and the roll is single cone-shaped roll, is provided with helical on the roll and rolls
Slot, and the precession direction of helical groove is identical as the precession direction in the aluminum alloy blank operation of rolling, cone angle gamma 1 is 15-17 degree,
And it is 40-300mm that roll, which bites the arc radius r of aluminum alloy blank, roll feed angle α is 13-15 degree, the roll off angle beta of roll
For 15-17 degree, the 89%-99% that the roll space D g between two rolls is aluminum alloy blank diameter D, roll rotational speed n are 25-
40r/min;
The aluminum alloy blank is 2219 rods and bars of aluminium alloy of large scale;
In the S5 step, the heating time of the operation of rolling is repeated are as follows: rods and bars of aluminium alloy diameter Dm × (0.3 ~ 0.4) min.
Preferably, roll small end face is set as arc surface, and circular arc radius surface is 40-300mm.
Preferably, Groove Ovality Factor is guide plate away from DdThe ratio between with roll spacing Dg, aluminum alloy blank is being deformed in S4 step
Groove Ovality Factor is used to be rolled for 1.28-1.45 in area.
Preferably, in the aluminum alloy blank operation of rolling, the roll spacing Dg between two rolls immobilizes, and is advantageously implemented
Multi-pass repeats to roll.
Preferably, the screw pitch ι of helical groove is 10 ~ 30mm, and the high h of tooth is 10 ~ 30mm.
Preferably, it is repeated in the operation of rolling in S5 step, deformed area shape remains unchanged.
Compared with prior art, the beneficial effects of the present invention are:
(1) deformed area is worn deep big, can obtain large scale entirety ultrafine-grained (UFG) microstructure.The plasticity of material internal during oblique milling
Deformation consists of two parts, first is that the compressive deformation between roll, this is deformed into periodic breaks deformation, and another part is to continue hair
Raw torsional deflection.The superposition of compression and torsional deflection is clearly distinguishable from generation in deformed area routinely to forge
Three-dimensional severe plastic deformation;(2) diameter of rod remains unchanged and reciprocally carries out multi- pass rolling before and after oblique milling.Oblique milling process exists
It spreads, the equivalent diameter in aluminum alloy blank cross section remains unchanged;(3) continuous-stable local deformation, rolling loads are small, deformation
Process is steady.The real contact area of workpiece and aluminum alloy blank is only the very little one of aluminum alloy blank surface area during oblique milling
Part deforms for localized contact, thus load is small;(4) pressure-torsion complex three-dimensional drastic deformation, it is thin can to obtain ideal crystal grain
Change effect.
Detailed description of the invention
Fig. 1 is roll schematic diagram of the present invention.
Fig. 2 is original structure β crystal grain schematic diagram.
Fig. 3 is that the rolling number of the embodiment of the present invention one is 2 schematic diagrames.
Fig. 4 is that the rolling number of the embodiment of the present invention one is 6 schematic diagrames.
Fig. 5 is each mold relative position of oblique milling process of the present invention.
Fig. 6 is each mold relative position top view of oblique milling process of the present invention.
Fig. 7 is that oblique milling of the present invention passes through each mold relative position left view of journey.
Fig. 8 is oblique milling process of the present invention deformed area schematic diagram.
Appended drawing reference: 1- roll, 2- aluminum alloy blank, 3- guide plate.
Specific embodiment
The roll spacings milling methods such as the helical tapered roll of large-sized aluminium alloy ultra fine grained steel bar of the present invention, comprising the following steps:
S1: selection diameter dimension D is 40-200mm, and length is the aluminum alloy blank 2 of 300-5000mm;
S2: above-mentioned aluminum alloy blank 2 being placed in heating furnace and is heated to 380-450 DEG C, heating time are as follows: aluminium alloy alloy
Blank diameter D × (0.6 ~ 0.8) min;
S3: the aluminum alloy blank 2 after heating is transported in skew rolling mill deflector chute from heating furnace, transhipment time 5-20s;
S4: carrying out feeding in the deflector chute of skew rolling mill, and aluminum alloy blank 2 is sent between skew rolling mill entrance and exit
Deformed area, aluminum alloy blank 2 is moved in deformed area inside spin to be terminated up to deforming, and obtains the rods and bars of aluminium alloy that diameter is Dm,
Middle m is rolling number, and the diameter for rolling the rods and bars of aluminium alloy once obtained is D1, rolls the straight of the rods and bars of aluminium alloy obtained twice
Diameter is D2, and so on;
S5: repeating above-mentioned S2-S4 step, obtains aluminium alloy to the 2-14 screw rolling of progress of aluminum alloy blank 2 and integrally surpasses
Fine grain bar;
The skew rolling mill is two-roller skew-rolling machine, and the roll 1 is single cone-shaped roll 1, is provided with helical on roll 1 and rolls
Slot, and the precession direction of helical groove is identical as the precession direction in 2 operation of rolling of aluminum alloy blank, cone angle gamma 1 is 15-17
Degree, and it is 40-300mm that roll 1, which bites the arc radius r of aluminum alloy blank 2,1 feed angle α of roll is 13-15 degree, roll 1
Roll off angle beta is 15-17 degree, the 89%-99% that the 1 space D g of roll between two rolls 1 is 2 diameter D of aluminum alloy blank, roll 1
Revolving speed n is 25-40r/min;
The aluminum alloy blank 2 is 2219 rods and bars of aluminium alloy of large scale;
In the S5 step, the heating time of the operation of rolling is repeated are as follows: rods and bars of aluminium alloy diameter Dm × (0.3 ~ 0.4) min.
1 small end face of roll is set as arc surface, and circular arc radius surface is 40-300mm.
Groove Ovality Factor is guide plate 3 away from DdThe ratio between with roll spacing Dg, aluminum alloy blank 2 is adopted in deformed area in S4 step
It is that 1.28-1.45 is rolled with Groove Ovality Factor.
In 2 operation of rolling of aluminum alloy blank, the roll spacing Dg between two rolls 1 immobilizes, and is advantageously implemented multiple tracks
It is secondary to repeat to roll.
The screw pitch ι of helical groove is 10 ~ 30mm, and the high h of tooth is 10 ~ 30mm.
It is repeated in the operation of rolling in S5 step, deformed area shape remains unchanged.
This patent is existed using tapered roll equal roll spacings rolling to rods and bars of aluminium alloy carries out, the advantage of such whole Ultra-fine Grained technique
In by 1 size Control of roll, roll 1 is longer for deformed area, and deformed area size is bigger, and is rolled by the helical on the tapered roll
The power-assisted of slot deforms, and on the basis of original deformation, then is superimposed small-scale compression and is bent shear-deformable, final realization super large modeling
Property deformation, have the function that refine crystal grain.Secondly deformation process is spiral feeding, therefore there are axial, radial and circumferential three
To effects of strain, deformed area penetrates with the obvious advantage.After aluminum alloy blank 2 is drawn into roll 1, cross section becomes ellipse,
During being threadingly advanced, since transverse radius is greater than 1 spacing of roll, aluminum alloy blank 2 bears always the small deformation of roll 1
Amount compression, the rotation of deformed area arbitrary point are turned around, twice by the compression of roll 1;Can repeated multiple times realization screw rolling, due to large hole
Type ellipse coefficient, the diameter of rod after screw rolling are greater than roll spacing, and deformed rolled piece can be repeated multiple times in same deformation
Under Parameter Conditions, by repeat-rolling, bigger deflection can be obtained in this way;Using larger feeding angle and big roll off angle, can obtain
It is more stable be threadingly advanced power, to adapt to the demand of large plastometric set, diameter dimension can be produced in 40-200mm, it is long
Spend 2219 aluminium alloy entirety ultra fine grained steel bars of the size within the scope of 300 ~ 5000mm.Therefore this patent is that large-sized aluminium alloy is whole
The industrialized production of body ultra fine grained steel bar provides the selection of an actuality.
The type of material processing is generally distinguished with recrystallization temperature, the above are hot-working, recrystallization temperatures for recrystallization temperature
The following are cold working, prior art preparation Ultra-fine Grained is all made of cold working, since deflection is inadequate, can only obtain so that dislocation is accumulative
Lesser crystal grain, but this crystal grain thermal stability is poor, not can be carried out heat treatment.The purpose of this patent is to obtain to be heat-treated
Crystal grain, i.e., Ultra-fine Grained is obtained in such a way that accumulation large deformation is by recrystallization, to be different from traditional cold working difference
It opens.
Embodiment one:
Using above-mentioned technical parameter, design processing screw rolling roll 1 is as shown in Figure 1;
S1: 2219 aluminium alloy of primary deformable parameters selection aluminium alloy, diameter 100mm, length 800mm;Spiral roll 1
Bite arc radius r be 60mm, tapered roll cone angle gamma 1 be 16 °, 13 ° of feed angle, roll off angle be 16 °, 1 screw pitch of spiral roll
It is 11mm for 13mm, the high h of tooth, 1 space D g of roll is the 90% of blank diameter D, Groove Ovality Factor 1.28,1 revolving speed of roll
For 32r/min;
S2: 380 DEG C of aluminium alloy cylindrical blank are heated in heating furnace, heating time is 70 minutes;
S3: the blank that would be heated to temperature is transported in punch deflector chute from heating furnace, transhipment time 10s;
S4: blank is moved in deformed area inside spin until deforming terminates.
S5: repeat-rolling 2 times and the analysis of 6 sub-samplings, significant for the effect of aluminum grain refinement, crystallite dimension is thin
It is small, and repeat the heating time of the operation of rolling are as follows: rods and bars of aluminium alloy diameter Dm × (0.3 ~ 0.4) min, wherein m is rolling number,
Rolling the diameter of rods and bars of aluminium alloy once obtained is D1, and rolling is that use diameter be the rods and bars of aluminium alloy of D1 as base twice
Material is rolled again, and the diameter of obtained rods and bars of aluminium alloy is D2, and so on, it repeats in the operation of rolling, becomes in S5 step
Shape area shape remains unchanged.
Based on examples detailed above, original structure is as shown in Fig. 2, average grain size is 70um or so;It uses present invention side
Method, Fig. 3 are to roll the crystal grain figure that number is 2, and wherein crystallite dimension is 10um or so, degree of grain refinement 85.7%;Fig. 3 is
The crystal grain figure that number is 6 is rolled, wherein crystallite dimension is 3um or so, degree of grain refinement 95.7%.Its working principle such as Fig. 8
Shown, the positional relationship between roll 1 and guide plate 3 is as shown in Fig. 5, Fig. 6 and Fig. 7.
In summary: provided by the present invention for the whole ultrafine grain preparation method thereof of rods and bars of aluminium alloy, passing through design spiral
The shape of tapered roll, and keep roll spacing in deformed area constant, multiple tracks repeatedly is carried out using super large deformed area Groove Ovality Factor
Secondary rolling is gradually accumulated as super large plastic deformation;Moreover, this method can multi-pass carry out screw rolling, for variety classes aluminium
Alloy rolls number within the scope of 2-14, and best for the effect of aluminum grain refinement, the whole Ultra-fine Grained size obtained is most
It is small.The technique is suitable for the continuous severe plastic deformation of rods and bars of aluminium alloy low load of various sizes specification and type.It is used to prepare
The integral fine crystal or ultra fine grained steel bar of 1000 ~ 3000nm.And existing severe plastic deformation rigid resistance can be overcome big, it can only process
The deficiency of small size workpiece.
The foregoing is only a preferred embodiment of the present invention, but scope of protection of the present invention is not limited thereto,
Anyone skilled in the art in the technical scope disclosed by the present invention, according to the technique and scheme of the present invention and its
Inventive concept is subject to equivalent substitution or change, should be covered by the protection scope of the present invention.