CN103706770B - A kind of disc-type single roller gets rid of the method that amorphous alloy ribbon prepared by band - Google Patents

Abstract

A kind of method that disc-type single roller melt_spun prepares amorphous alloy ribbon, belongs to alloy thin band preparing technical field.The present invention uses disc type running roller, melt jet is in the disc surfaces rotated around disc centre axle, the direction making centrifugal force suffered by melt is parallel with contact surface i.e. disc surfaces, under disk border amorphous thin ribbon cooling autogenous shrinkage and centrifugal action, it is spontaneously decoupled running roller, forms amorphous alloy ribbon.Gained strip size is thinner, surface smoothness is higher, performance is more preferable.

Description

A kind of disc-type single roller gets rid of the method that amorphous alloy ribbon prepared by band

Technical field

The invention belongs to alloy thin band preparing technical field, relate to a kind of novel single roller and get rid of band method and get rid of band process with certainly solution Middle fluid spills, being difficult to into the problem of band, specifically a kind of disc-type single roller gets rid of band method.

Technical background

The rotation of single-roller rapid quenching with quenching, also known as melt cold roller solidifying method, continuous casting of thin strip method.The production amorphous invented than Dare (Bedell) The method of state band, as depicted in figs. 1 and 2.Motlten metal is injected in the chill roll surface of high speed rotating and makees in gravity, moistening Weld pool is become by lower berth spread；The boundary layer that weld pool contacts with chill roll is solidified by chilling, and rotates together with continuation with chill roll It is cooled into metal sheet band；Depart under metal sheet band autogenous shrinkage and centrifugal action running roller rim faces [first spring in spring, Li Derong. The characteristic [J] of planar flow casting puddle. Harbin Institute of Technology's journal, 2000,24(4): 273 274].

F_{Frictional force}: running roller and melt contacts face form one layer of thin solidification layer and are attached to roller surface and are added by rotating running roller , there is velocity gradient in speed, with running roller contact surface speed is relatively big, free surface velocity is less, mutually move inside melt institute in melt The power being subject to, is expressed as F_{Frictional force}。

F_{Adhesive force}: refer to that certain material is attached to the ability of another kind of material surface, refer specifically to melt at this and be attached to running roller table The ability in face.

F_{Centrifugal force}: molten metal is accelerated to rotate with running roller by running roller, and produces the centrifugal force departing from center of rotation.

During single-roller rapid quenching with quenching gets rid of band, melt is by centrifugal force F_{Centrifugal force}, adhesive force F_{Adhesive force}, tangential stress F_{Frictional force}Common work With.

Weld pool: refer to that molten metal out becomes the liquid-solid metal development area of definite shape from nozzle at roller surface row, Complete molten metal in this region to sprawl, solidify.

Running roller high speed rotating provides tangential stress F to weld pool_{Frictional force}And drive weld pool to move to equidirectional.Fig. 3 It is melt pull amorphous wire initial weld pool pattern (solid line) and weld pool pattern (dotted line) during preparing amorphous wire, permissible from figure Find out that in melt draw process, melted moistening between foundry alloy and running roller and static moistening have significantly difference [Yu Shengsheng, grandson Sword flies .CoFeSiB alloy melt pull filamentation characteristic research [D]. Harbin Institute of Technology (Harbin), 2011:5 6].Molten In body draw process, there is acute variation along the direction that running roller rotates in weld pool pattern；Angle of wetting is by static angle of wetting θ simultaneously_e Become contacts upstream angle θ_uWith downstream contact angle θ_d, wherein can reflect melted foundry alloy dynamic wettability on running roller is θ_d, θ_dThe least, dynamic wettability is the best, and the direction that weld pool more rotates toward wheel disc changes.S.olsen【M.Allahverdi, Robin A.L.Drew,Strom‐Olsen.Wetting and melt extractioncharacteristics of ZrO2‐Al2O3based materials[J].Journal of American CeramicSociety.1997,80:2910‐ 2916] etc. it is found that while static wettability very poor (angle of wetting reaches 140 ° 160 °), but the existence of tangential stress causes dynamic moisture Angle is the least, and wettability is improved.M.Allahverdi etc. [Huang Shiying. single roller chilling method forms the power of amorphous ribbon Learn equation group and checking III [J] thereof. instrument material .1985,18 (4): 160 164] obtain difference by high speed photography The dynamic moisture of the molten metal drop under wheel disc rotating speed and weld pool pattern, molten bath length L and thickness δ；Increase along with wheel speed V Tangential stress F_{Frictional force}Increasing, melt spreading area is the biggest.

It is outside that prior art melt is perpendicular to running roller contact surface by centrifugal force, and centrifugal force makes melt tend to the running roller that comes off Surface rather than sprawl at roller surface, when centrifugal force is more than adhesive force, the most insufficient cooling running roller that just comes off of molten metal Surface, forms fluid spills phenomenon.Such as rotating speed 40m/s, roller diameter 0.4m, centrifugal acceleration suffered by liquid metals reaches 816g, it is easy to fluid spills phenomenon occurs.

Prior art, for making melt effectively can sprawl at roller surface, improves the wettability of running roller and melt, needs to consider Viscosity (μ), surface tension (γ), wettability, surface roughness (Ra), temperature (T), phase transformation factor, regulation melt jet speed, Multiple parameters such as angle, distance, roller speed, running roller material wettability, increase process complexity, glue for some molten metal The molten metal material that degree is big and running roller moistening is the best, in any case adjusting process parameter is all difficult to into band, can not get surface light Rapidly solidified material sliding, uniform [Mao Zhonghan. the manufacture method [J] of amorphous alloy. rare metal alloy is processed, and 1980, 01:11 15].

Amorphous or metastable phase, have the performance of the aspects such as superior mechanics, optics, magnetics, in order to obtain required amorphous Or metastable phase crystallite band, need 10⁶-10⁸Cooldown rate during more than K/s.Have learned that the heat-transferring method fast quenching process is total is main For Newtonian Cooling:

${\left(\frac{\mathrm{dT}}{d\mathrm{\τ}}\right)}_{\max }=\frac{\mathrm{\α}}{{\mathrm{\ρ}}_l{C}_{\mathrm{pl}}h}(T_m\−T_0)\text{\  \  \  \  \  \  \  \  \ \ }\left(1\right)$

ρ_lFor metal liquid density, С_plFor metal liquid phase specific heat at constant pressure, α aluminium alloy turns hot coefficient with chill roll.H is The thickness of metal sheet band.As can be seen here, rate of cooling is inversely proportional to the thickness of alloy thin band, is directly proportional to roller speed.

Existing technology uses the rotating speed strengthening running roller to improve cooldown rate.When wheel disc rotating speed brings up to a certain degree Time, thickness of strip does not decline how many, and strip surface draw vestige too big, surface roughness strengthens, and occurs netted and empty, Affecting strip quality, centrifugal force strengthens simultaneously, and melt is easily caused fluid spills phenomenon under centrifugal action, and impact produces peace Entirely.So chill roll rotating speed typically can not be too big, linear velocity is less than 35m/s.

Prior art take be reduce nozzle size reduce get rid of tape thickness, improve rate of cooling, but by melt gold Belonging to the impact of purity, nozzle is easily blocked by the impurity in molten metal and stops spray band, and the unit interval flows through the gold of nozzle simultaneously Belonging to flow quantity too small, at nozzle, metal liquid is because constantly cooling solidification and plug nozzle, so the diameter of nozzle can not mistake Little, generally 0.6-0.12 millimeter, molten metal to keep certain degree of superheat simultaneously, to ensure continuous print spray band.Existing In technical conditions, due to technology and the restriction of method, can only spray for the amorphous alloy strips of 30-60 micron.

Existing technology is exactly to use the running roller material of high heat conductance, but along with the raising of wheel disc thermal conductivity, melt pull After unit interval, weld pool inner melt residuals temperatures is gradually lowered, and solidification required time is the shortest, and melt is spreading area on running roller The least, wettability is the poorest, and tapability can be the poorest.When selecting metal wheel disc, rate of cooling and tapability can enough be taken into account.

R wave: refer to that the metal of fluid column or ot-yet-hardened presents under the comprehensive function of surface tension and gravity certain The periodic dimple of rule

Prior art is prepared amorphous band surface and is easily formed R wave defect and being involved in property gas hole.Work as roller speed Forming eddy current time relatively low around the band scope of freedom and cause melt pull layer disturbance, amorphous ribbon surface easily forms R wave.Whole The forming process of R wave can be divided into 3 stages: (1) melt contacts with running roller；(2) melt pull layer is with running roller associated movement； (3) melt pull layer separates with running roller.When running roller and melt contacts, due to the chilling action that wheel disc is most advanced and sophisticated, formed one layer non- The thinnest solidification layer, this solidification layer can be considered heat boundary region δ_T.Momentum boundary layer δ_VIt is far longer than heat boundary region δ_T, heat extraction amount boundary region δ_TOuter whole momentum boundary layer δ_VBeing in liquid, melt pull layer running roller associated movement melt is by disturbance Rear R wave is formed in liquid.When semi-solid boundary region flight in protective gas, owing to now having been detached from Wheel rim, process of setting mainly carries out conduction of heat by convection current and radiation, and rate of cooling reduces rapidly, causes R wave size to be entered One step extension, forms R wave defect.When wheel disc rotating speed is higher, being involved in of protective gas causes melt pull layer the completeest Full solidification is just ruptured.

Patent (200810247383.7) proposes a kind of method by improving liquid metal alloy jet velocity and obtains Smooth surface, uniform rapidly solidified material, but and can only deciding section material get rid of band problem, for high viscosity, do not moisten Wet alloy melt can't solve [Zhang Bo, Li Wen, Li Hong, metal drop moistening above substrate and below substrate very well Journal of Sex Research [J], sufacing, 2009,02:4 6].

So, the most certainly solving single-roller rapid quenching with quenching tapability energy, exploitation new equipment new technology necessitates.

Summary of the invention

It is an object of the invention to provide a kind of new band method of getting rid of, under equal conditions overcome the problems of the prior art, I.e. solve single roller coagulate soon fast solidifying strip melt fluid spills in thin strip process, be difficult to into band, there is Rayleigh defect, bubble etc. and ask in strip Topic, preparation is a kind of, and size is thinner, surface smoothness is higher, the more preferable fast quenching amorphous alloy ribbon of performance.

It is: change the structure of running roller to use disc type running roller i.e. with molten for certainly solving the core scheme of the problems referred to above present invention Body contact face be disc, whole running roller is in the form of annular discs, melt jet in the disc surfaces rotated around disc centre axle (as Fig. 4), the direction making centrifugal force suffered by melt is parallel with contact surface i.e. disc surfaces, cools down self at disk border amorphous thin ribbon Shrink and under centrifugal action, be spontaneously decoupled running roller, forming amorphous alloy ribbon.

The direction of centrifugal force of the present invention is upwards become one side parallel with contact surface from the contact surface that is perpendicular to of prior art Can reduce perpendicular contact towards upper centrifugal force, solve the problem that melt splashes, on the other hand centrifugal force is parallel with contact surface, energy Improve dynamic wettability (such as Fig. 3), with F_{Frictional force}Promote that melt is the most quickly sprawled along disk on the contact surface together.

The present invention has opened up and a kind of new has got rid of band method, and getting rid of the design parameter during band can be carried out according to specific circumstances Regulating, the disc-type single roller of the present invention is got rid of band method, is characterized in:

(1) disk is internal leads to cooling water and rotates along central shaft, and disc surfaces is as contact surface and central axis, preferably Disc surfaces level is upwards.

(2) melt material melts through smelting furnace, is injected in disc surfaces through nozzle.

(3) melt forms weld pool in disc surfaces, and centrifugal force, frictional force, wetting power, gravity act on lower melt paving jointly Exhibition, and it is cooled into thin and smooth amorphous thin ribbon.

(4) under disk border amorphous thin ribbon cooling autogenous shrinkage and centrifugal action, it is spontaneously decoupled running roller.

Compared with prior art, the invention has the beneficial effects as follows

1. in prior art, metal is sprayed on the outer surface of running roller, and metal bath is perpendicular to running roller contact surface by centrifugal force Outwards (Fig. 1), melt effectively can not be sprawled at roller surface, and when centrifugal force is more than wetting power, molten metal is the coldest The most just come off roller surface, forms fluid spills phenomenon.The present invention changes roller type as disc type into makes centrifugal force direction change Become, upwards become parallel with contact surface from being perpendicular to contact surface, on the one hand can reduce perpendicular contact towards upper centrifugal force, solution The problem splashed by melt.On the other hand centrifugal force and F_{Frictional force}Jointly the quickest along disk in disc surfaces under effect Sprawl, form smooth surface band in uniform thickness.Can prepare thinner, need the faster amorphous band of rate of cooling.

2. prior art ensures Melt Stability and prevents the essential condition of spray nozzle clogging, and the temperature of weld pool keeps certain mistake Temperature, uses the running roller material (such as copper roller, molybdenum roller) of high heat conductance, although can guarantee that the rate of cooling of melt, but melt pull After unit interval, weld pool inner melt residuals temperatures is relatively low, and solidification required time is too short, and melt does not has enough time to spread on running roller Exhibition just solidification, is unfavorable for that melt is sprawled, and tapability can be poor；The present invention is molten takes out layer under F centrifugal force and F frictional force pull effect Spreading rate is very fast, and melt spreading area is relatively big, and tapability can be preferably.

The most existing technology uses high rotating speed to obtain enough degree of supercoolings, and high rotating speed easily makes to protect around weld pool Property gas be involved in weld pool, simultaneously melt with running roller rotate deflect, too high rotating speed be easily caused melt pull layer occur Fracture.And one aspect of the present invention takes out layer at F due to molten_{Centrifugal force}And F_{Frictional force}Quickly sprawl under pull effect, under low roller speed Just can obtain enough rate of cooling and strip spreading area, it is not necessary to too high rotating speed.

Can only obtain the thickness amorphous ribbon more than 20 microns under the most existing technical conditions, but also often occur that nozzle blocks up Plug interrupts spray band or belt phenomenon, or the defects such as cavity and R wave occurs, and production efficiency is the highest.Melt of the present invention is at F_{Centrifugal force}With F_{Frictional force}Accelerating the speed sprawled under pull effect, after the melt pull unit interval, weld pool residuals temperatures raises, and melt is on running roller Sprawl region increase, thickness less, it is not necessary to just can obtain the thinnest amorphous ribbon with too small nozzle, not have spray nozzle clogging and show As, improve width and the spray band efficiency of amorphous ribbon simultaneously.

5. during prior art gets rid of band, easily form R wave defect.The present invention at melt at F_{Centrifugal force}And F_{Frictional force}Pull is made Sprawling the thinnest with lower melt, and rapid condensation is solid-state, R wave can only be to be formed in liquid, reduces R wave defect Generation, it is thus achieved that ganoid strip.

Figure of description

Fig. 1 single-roller rapid quenching with quenching prepares thin strip process schematic diagram

1, chill roll 2, molten metal injection 3, molten metal 4, coagulate strip soon；

The mono-roller of Fig. 2 coagulates thin strip process weld pool schematic diagram soon

1, chill roll 2, molten metal injection 3, molten metal 4, coagulate strip soon；

Dynamic wettability under Fig. 3 shearing stress effect

1, liquid metals 2, roller surface.θ_eStatic contact angle, θ_uContacts upstream angle, θ_dDownstream contact angle.Solid line weld pool Static pattern, dotted line weld pool dynamic profile figure

Fig. 4 disc-type single roller of the present invention gets rid of band method centrifugal force and wettability principle schematic

1, disc type chill roll 2, metal bath 3, weld pool 4, coagulate strip soon；

Fig. 5 disc-type single roller embodiment schematic diagram

1, dragging motor 2, running roller 3, molten metal nozzle 4, valve 5, Pressure gauge 6, metal molten stove.

Detailed description of the invention

Below in conjunction with the detailed description of the invention of the embodiment detailed description present invention, but the detailed description of the invention of the present invention not office It is limited to following example.

Embodiment 1:

The preparation method of a kind of fast quenching amorphous alloy ribbon, including dispensing, melting, secondary smelting, spray band, collects, and it is changed Ingredient percent is: 21.57%Sm, 72.84%Fe, 1.66%Zr, 3.93%Co.

It is raw material by 99.5% samarium metal, ingot iron, metallic cobalt, metal zirconium, uses intermediate frequency vacuum induction melting furnace to melt Refining, at vacuum cavity elder generation evacuation before melting, then using high-purity argon gas is protective gas, it is to avoid alloy oxidation.Melting temperature Degree is 1600 DEG C.Secondary fusion in sensingization ladle, sets up spray band pressure in nozzle bag, and spray band pressure is 0.05Mpa. Protective atmosphere pressure is 0.01Mpa.

The plane weld pool that in spray band step, nozzle and chill roll form dynamic stability, sprawl to both direction, weld pool temperature It it is 700～1300 DEG C.

It is prepared as disc type plane running roller, the internal logical circulating water of plane running roller with molybdenum.The a diameter of 400mm of straight roll, Running roller edge line speed is 20m/s.Chill roll finish turning in place: ensure rolling surface roughness Ra < 0.2 μm.

Nozzle bore 0.5mm, nozzle is near running roller edge, from running roller edge 20mm.

Molten metal quickly cools down after being ejected into roller surface, forms fast solidifying strip.Molten metal is ejected into roller surface The most quickly sprawl cooling, form amorphous thin ribbon, under disk border cooling autogenous shrinkage and centrifugal action, be spontaneously decoupled running roller. And to obtain thickness be 10～15 microns of uniform strips, surface roughness is less than the Sm of 0.25 μm_1.0Zr_0.3Fe_8.1Co_0.6Fast solidifying thin Band.During splash phenomena does not occur, alloy does not occur α Fe soft magnetism phase, through grinding, nitridation formed Sm_1.0Zr_0.3Fe_8.1Co_0.6N_x, after making bonded permanent magnet, magnetic property is B_r=1.07T, (BH)_max=22.5MGOe, concrete preparation Equipment is shown in schematic diagram 5.

And the parameters such as the composition of comparative example 1, roller diameter, roller speed, jet size are same as in Example 1, institute is different Be use roller type get rid of band method.It is poor that comparative example 1 obtains strip profile uniformity, there is not of uniform size the coagulating soon of different morphologies Alloy, occurs that part occurs fluid spills phenomenon, the Sm of spheroidal particle occurs_1.0Zr_0.3Fe_8.1Co_0.6Fast solidifying alloy, exists a large amount of α-Fe、SmFe₃Phase, magnetic energy product is less.

Table 1, embodiment contrast with comparative example

Embodiment 2:

The circular cone that the present embodiment uses makes to coagulate soon thin strip process, high-performance Sm of preparation_1.0Zr_0.3Fe_8.1Co_0.6Fast solidifying strip, The thickness of strip, width are shown in Table 2.Except that use the rotating speed 40m/s at running roller edge, other are such as embodiment 1.

Comparative example 2, uses roller type to coagulate thin strip process soon, and other parameters such as embodiment 2 is got rid of extremely unstable during band, gone out Having showed part melt splash phenomena, obtained strip profile uniformity poor, sheet thickness 15～30 microns, same making also occurs in a large number Graininess, bar-shaped fast gel material, graininess, club α-Fe phase XRD diffraction maximum higher, through grinding, nitrogenize, bond Sm_1.0Zr_0.3Fe_8.1Co_0.6N_xMagnet magnetic energy product is less.

Table 2, embodiment contrast with comparative example

Claims (1)

1. a preparation method for fast quenching amorphous alloy ribbon, including dispensing, melting, secondary smelting, spray band, collects, its chemistry Ingredient percent is: 21.57%Sm, 72.84%Fe, 1.66%Zr, 3.93%Co；

It is raw material by 99.5% samarium metal, ingot iron, metallic cobalt, metal zirconium, uses intermediate frequency vacuum induction melting furnace melting, At vacuum cavity elder generation evacuation before melting, then using high-purity argon gas is protective gas, it is to avoid alloy oxidation；Smelting temperature is 1600 DEG C, secondary fusion in sensingization ladle, nozzle bag is set up spray band pressure, spray band pressure is 0.05Mpa, protects gas Atmosphere pressure is 0.01MPa；

The plane weld pool that in spray band step, nozzle and chill roll form dynamic stability, sprawl to both direction, weld pool temperature is 700 ～1300 DEG C；

It is prepared as disc type plane running roller with molybdenum, the internal logical circulating water of plane running roller, a diameter of 400mm of straight roll, running roller Edge line speed is 20m/s；Chill roll finish turning in place: ensure roll surface roughness Ra < 0.2 μm；

Nozzle bore 0.5mm, nozzle is near running roller edge, from running roller edge 20mm；Molten metal is fast after being ejected into roller surface Quickly cooling but, forms fast solidifying strip；Molten metal quickly sprawls cooling after being ejected into roller surface, form amorphous thin ribbon, at disk It is spontaneously decoupled running roller under edge cooling autogenous shrinkage and centrifugal action.