The method and the device of online composition detection of magnesium alloy and solidified structure control
Technical field
The present invention relates to the detection that a kind of alloy prepares process, the method and the device of control; Be particularly related to a kind of online composition detection of magnesium alloy of stokehold melt check and method and apparatus of solidified structure control of being used for; Be particularly useful for magnesium alloy large-sized ingot casting and intricate casting forming process, belong to metal material and metallurgical technology field.
Background technology
As everyone knows, the initial solidification tissue of alloy material directly influences the microstructure and property of final products, and many factors such as smelting technology, casting technique, alloying component all produce very big influence to solidification of Al and solidified structure.In magnesium alloy fused mass, add alloying element, alterant and fining agent, all can control size, distribution and the pattern of crystal grain and precipitated phase in the solidified structure, and improve magnesium alloy mechanical property with this, the most commonly used in commercial production.But, because magnesium alloy is easy to oxidation and burning, it is but also not fully up to expectations in actual production in magnesium alloy fused mass, to add experimental implementation such as alloying element, alterant and fining agent, and common metal such as the iron and steel that is far from, aluminium alloy and copper is such ripe.Because technological operation is empirical very strong; Time of repose, cast situation receive appointed condition and artificial factor very big; Therefore improper operation can cause scaling loss, the alterant of alloying element the poisoning of dissipation, fining agent with rotten etc.; Make the solidified structure that obtains compare far from each other with expection; Finally cause the raising of reduction, the shortening of equipment life, the prolongation of production cycle and the production cost of product percent of pass, these all are disadvantageous to conventional cast enterprise, are difficult to especially accept for the examination of some large complicated foundry goods, equipment etc.In addition, the magnesium alloy fused mass after the melting can not in time be poured into a mould sometimes, and after this length of melt time of repose is still uncertain to the influence that alloying element, alterant and fining agent dissipate.Based on above-mentioned factor, be necessary before the cast magnesium alloy fused mass is checked again, with the quality of judgement melt, and implement corresponding the processing.But, still not can be applicable to the method or the equipment of the control of online composition detection of magnesium alloy and solidified structure at present.
Therefore; The development of developing the control method of online composition detection of a kind of magnesium alloy and solidified structure and installing China's magnesium alloy industry has positive effect; Fundamentally solve most of difficult problems that exist in the magnesium alloy founding for a long time, comprise quantitative compensation after the alloying element scaling loss, system optimization modification process, accurately control thinning effect etc., thereby realize stokehold check, online evaluation, on-the-spot guidance production; The final qualification rate that improves product; Shorten the production cycle, and then reduce production costs, prolong service life of equipment.
Thermoanalysis technology utilizes the fuel factor of alloy phase change process can analyze the process of alloy graining, in the work of setting up phasor, is widely used.Be used to measure the phosphorus content of cast iron and steel in early days, be used for measuring the status degenerativus and the degree of grain refinement of aluminium alloy silicon afterwards.To the end of the eighties in last century, the tame aluminium alloy casting in the whole world existing more than 600 factory has set up the modern TAS of monitoring the molten alloy quality.For magnesium alloy; Application number is that the Chinese patent of 200710011227.6 (publication number is CN101303319B) provides a kind of magnesium and rotten hot analyzing detecting method of tissue thinning effect and the device handled of magnesium alloy; But this invention only can detect the modification effect of alloy, can't carry out online detection to the dissipation situation of alloying element, alterant and the fining agent of magnesium alloy.
Cooling curve in the alloy graining process is regarded as " fingerprint " of alloy by people, and it and alloy graining are organized closely related, two identical cooling curves, and its corresponding alloy graining is organized and also is considered to duplicate.Each details of alloy structure forming process can be analyzed from cooling curve and obtain.Along with increase cool time, cooling curve generally is dull downward trend, corresponding different solidification stages in the magnesium alloy in course of solidification.Theoretical according to forming core, known that the degree of metamorphism of several characteristic temperature and melt is arranged on the cooling curve is closely related, like T
α-n, T
α-min, T
α-g, T
Eu-n, T
Eu-gAnd T
sDeng, the meaning of its representative corresponds to initial forming core temperature, recalescence preceding minimum temperature, recalescence temperature, the initial forming core temperature of eutectic, eutectic growth temperature successively and solidifies end temp etc.Wherein, recalescence is meant the phenomenon that the latent heat that discharges in the metal solidification process makes that melt temperature improves.(S.G.Shabestari, M.Malekan.Journal of Alloys and Compounds, 2010,492 (1-2): 134-142.) studied the scaling method that magnesium alloy α solidifies characteristic parameter mutually such as S.G.Shabestari; And C.M.Gourlay etc. (C.M.Gourlay, A.K.Dahle.Nature, 2007,445:70-73.) developed the scaling method that magnesium alloy β solidifies characteristic parameter mutually.Under the non-special curing condition, the amplitude of recalescence phenomenon is very little in the magnesium alloy in course of solidification, and the latent heat of solidification of this and magnesium has direct relation for a short time.Application number is that the Chinese patent of 200710011227.6 (publication number is CN101303319B) passes through the control cooldown rate to amplify the recalescence phenomenon, quantizes to compare the purpose that recalescence exothermic peak area realizes estimating modification effect then.Big quantity research proves that the adjustment curing condition can make the recalescence phenomenon in the magnesium alloy in course of solidification more obvious, is suitable for the demarcation or the evaluation work in later stage.But the change of this condition often need increase extra complicated technology and auxiliary equipment, controls mold temperature, accurately adjusts cooldown rate, increase mould corollary apparatus etc. such as strictness, is unfavorable for that very the scene of analytical test work is launched.In addition, after adding a certain amount of fining agent in the magnesium melt, the amplitude of recalescence phenomenon will be very little, be oblique line shape sometimes even directly.In sum, be badly in need of setting up a kind of reliable and stable online composition detection and the method for solidified structure control in the magnesium alloy thermoanalysis technology.
Summary of the invention
The present invention is directed to the deficiency of above-mentioned prior art; The method of online composition detection of a kind of magnesium alloy and solidified structure control is provided, a kind of device of realizing this method is provided simultaneously, be intended to through the constant volume mould; Gather the melt cooling curve; Standard cooling curve in the comparison database is grouped into becoming in the alloy melt, the content of alterant and fining agent carries out on-line analysis and adjustment, realizes the target of control solidified structure.
The present invention realizes through following technical scheme:
The method of online composition detection of a kind of magnesium alloy and solidified structure control; It adopts meter ladle to extract magnesium alloy fused mass, constant volume mould control melt thermal capacitance, thermocouple The real time measure melt temperature; Temperature over time in temperature acquisition system collection and the record melt solidifying process; Call the comparison that the cast magnesium alloy database carries out the Hirschfeld-Klinger reaction characteristic parameter through computer, then chemical composition, alterant, fining agent content in the alloy melt are adjusted, finally control solidified structure.
The method of online composition detection of magnesium alloy of the present invention and solidified structure control, it comprises following concrete steps:
1), comprises and add alloying element, alterant and fining agent according to normal smelting technology melting magnesium alloy in crucible;
2) thermocouple is fixed in the ad-hoc location of constant volume mould through positioning fixture;
3) Installation and Debugging temperature acquisition system;
4) adopt the meter ladle after the preheating from crucible, to take out melt, the thermocouple measurement temperature treats that melt temperature reduces to the detected temperatures that is suitable for temperature acquisition system, is poured in the constant volume mould;
5) computer control temperature acquisition system collection and write down the temperature-time data of tested melt solidifying process; And computer is handled through the routine analyzer of inherence: set up heat according to the temperature of gathering-time real time data and analyze cooling curve; And this curve is carried out first derivation obtain cooling-rate curves; According to the standard boost line, to the actual characteristic parameter that solidifies of magnesium alloy fused mass: actual initial forming core temperature T
α-n is real, the initial forming core temperature T of actual eutectic
Eu-n is real, actual eutectic growth temperature T
Eu-g is real, the actual end temp T that solidifies
S is real, actual eutectic growth time t
Eu-g is realWith the actual concluding time t that solidifies
S is realDemarcate;
6) plan obtains the standard analysis of alloy to computer and the standard of solidified structure is solidified characteristic parameter: the initial forming core temperature T of standard by transferring in the cast magnesium alloy database
α-n mark, the initial forming core temperature T of standard eutectic
The eu-n mark, standard eutectic growth temperature T
The eu-g mark, standard solidifies end temp T
The s mark, standard eutectic growth time t
The eu-g markSolidify concluding time t with standard
The s mark, and it actual characteristic parameter that solidifies with tested melt compared, work as T
Eu-n is real>T
The eu-n markThe time, add corresponding alloying element; Work as T
α-n is real<T
α-n MarkThe time, replenish fining agent; As (t
S is real-t
Eu-g is real)>(t
The s mark-t
The eu-g mark) time, the addition of increase alterant.
The method of online composition detection of magnesium alloy of the present invention and solidified structure control; Its operation 4) in, said detected temperatures is 500 ℃-900 ℃, and the temperature of said constant volume mould is controlled at-30 ℃-100 ℃; When from crucible, taking a sample; Meter ladle stopped in melt 0-10 minute, and the pre-heating mean of meter ladle is: put meter ladle for a long time in preheating furnace, preheat temperature is controlled between 200 ℃-800 ℃.
Another technical scheme provided by the invention is:
A kind of device of implementing the method for online composition detection of above-mentioned magnesium alloy and solidified structure control; The meter ladle that it comprises positioning fixture, thermocouple, temperature acquisition system, computer, stores the cast magnesium alloy database of standard magnesium alloy data, is used to hold the constant volume mould of tested melt and is used for the melt sampling; Said thermocouple connects temperature acquisition system; And fixedly be suspended in the tested melt in the constant volume mould through positioning fixture; Said temperature acquisition system is connected with computer; And the temperature-time data of the tested melt solidifying process of gathering and writing down to computer transmission institute, said computer is connected with the cast magnesium alloy database, and transfers standard by it and solidify the actual characteristic parameter that solidifies of characteristic parameter and tested melt and compare.
The device of online composition detection of magnesium alloy of the present invention and solidified structure control, its constant volume mould is formed by steel, iron, graphite, clay-bonded sand, resin sand, pottery or fire clay manufacturing.
Check and analysis technology mechanism of the present invention is following:
According to Transformation Principle; When forming a large amount of nucleus in the liquid metal; The minimizing of slope absolute value can take place in cooling curve; Cooling-rate curves will present the trend of " rising-decline ", and " flex point " occur, cross the crossing point of straight line that this point makes to be parallel to temperature axis and cooling curve corresponding be exactly initial nucleation temperature T
α-nAccording to solidifying principle, make the baseline of cooldown rate change curve, except that self shook, this line and cooldown rate change curve had four intersection points, and the corresponding respectively characteristic parameter that solidifies is T
α-min, T
α-g, T
Eu-nAnd T
Eu-gAt T
Eu-gAfter the point, cooling-rate curves can be " declines-risings " shape, occurs " flex point ", cross the crossing point of straight line that this some work is parallel to temperature axis and cooling curve corresponding be exactly to solidify end temp T
sAspect the solidified structure prediction, according to solidifying forming core principle, T
α-min-T
α-gValue big more, the α-Mg that obtains organizes tiny more, promptly thinning effect is good more; T
Eu-n-T
Eu-gValue big more, the degree of scatter of eutectic structure is good more.According to crystal growth kinetics, t
s-t
Eu-gValue more little, the eutectic structure that obtains is tiny more, promptly modification effect is good more.
The present invention according to classical solidification theory, carries out accurate composition measurement and solidified structure prediction to melt through alloy " fingerprint ", can effectively control alloying element, alterant, fining agent, and energy field inoculation(effect) effect.Adopt data acquisition software, Database Systems, DAS; Analysis through the computer realization melt state; Common formation magnesium and online composition detection of magnesium alloy and solidified structure control device, it comprises melt quantitative casting ladle, constant volume mould, positioning fixture, temperature acquisition system, computer, cast magnesium alloy Database Systems and data analysis system.Detection method of the present invention and checkout gear are used for the melting scene of magnesium and magnesium alloy; As the on-the-spot sample analysis means; Before cast, detect the composition of molten alloy,, the content of melt associated alloys element is adjusted according to the solidified structure predictive analysis results; Control and raising metallurgical quality reduce production cost.
Compared with prior art, the present invention has following advantage:
1, the present invention adopts the alloying component of heat analysis method detection melt, and is simple, compares with dissecting the foundry goods detection method, and analysis cost reduces;
2, the present invention can measure the composition of a large amount of melts, and sense cycle is short, is suitable for the stokehold check, is convenient to instruct and produces;
3, checkout gear automation of the present invention, the result is accurate, and reliability is high.
This method has the advantage that the result is stable, reliability is high, analytical cycle is short, automatization level is high; Can effectively improve ingot casting, casting quality; Reduce production costs, reduce the production cycle; Satisfy the production needs of China magnesium alloy enterprise, meet the requirement of magnesium alloy national project research and development strategy, have bigger market popularization value.The present invention is suitable for containing the zirconium series magnesium alloy and the online composition detection that do not contain the zirconium series magnesium alloy, like: AZ series, ZK is serial, AM is serial and MgRE series etc.
Description of drawings
Fig. 1 is a structural representation of the present invention.
Fig. 2 is the vertical view of constant volume mould of the present invention and positioning fixture.
Fig. 3 solidifies the parameter calibration sketch map for the cooling curve characteristic.
Fig. 4 (a) and (b) be that the WE43 magnesium alloy replenishes the solidified structure metallograph before and after the Mg-Y intermediate alloy among the embodiment 1.
Fig. 5 (a) and (b) be that the AZ31 magnesium alloy replenishes the solidified structure metallograph before and after the pure Al among the embodiment 2.
Fig. 6 (a) and (b) be that the WE54 magnesium alloy replenishes the solidified structure metallograph before and after the Mg-Zr intermediate alloy among the embodiment 2.
In above-mentioned accompanying drawing, 1-meter ladle, 2-positioning fixture, 3-thermocouple, 4-temperature acquisition system, 5-computer, 6-cast magnesium alloy database, 7-constant volume mould.
The specific embodiment
Below in conjunction with accompanying drawing embodiments of the invention are elaborated, present embodiment is to have provided detailed embodiment and concrete operating process under the prerequisite with technical scheme of the present invention, but protection scope of the present invention is not limited only to following embodiment.
The method of online composition detection of magnesium alloy of the present invention and solidified structure control is to implement through online composition detection of magnesium alloy shown in Figure 1 and solidified structure control device; As shown in Figure 1, this device comprises positioning fixture 2, thermocouple 3, temperature acquisition system 4, computer 5, cast magnesium alloy database 6, constant volume mould 7 and meter ladle 1.Said meter ladle 1 is used for the melt sampling.Said constant volume mould 7 is used to hold tested melt, and it is formed by steel, iron, graphite, clay-bonded sand, resin sand, pottery or fire clay manufacturing, to satisfy the requirement of different cooling rate.Said thermocouple 3 connects temperature acquisition system 4, and as shown in Figure 2, this thermocouple 3 fixedly is suspended in the tested melt in the constant volume mould 7 through positioning fixture 2.Said temperature acquisition system 4 is connected with computer 5, and the temperature-time data of the tested melt solidifying process of gathering and writing down to 3 of thermocouples of computer 5 transmission.Said computer 5 is connected with cast magnesium alloy database 6; Store the data of standard magnesium alloy in this cast magnesium alloy database 6; This computer 5 solidifies characteristic parameter by transferring standard in the cast magnesium alloy database 6, and compares with the actual characteristic parameter that solidifies of tested melt.
As shown in Figure 1; The method of online composition detection of magnesium alloy of the present invention and solidified structure control adopts meter ladle 1 to extract magnesium alloy fused mass; Constant volume mould 7 control melt thermal capacitances, thermocouple 3 The real time measure melt temperatures, temperature is over time in temperature acquisition system 4 collections and the record melt solidifying process; Call cast magnesium alloy database 6 through computer 5; And carry out the comparison of Hirschfeld-Klinger reaction characteristic parameter, and then chemical composition, alterant, fining agent content in the alloy melt are adjusted, finally control solidified structure.
Method of the present invention comprises following concrete steps:
1), comprises and add alloying element, alterant and fining agent according to normal smelting technology melting magnesium alloy in crucible.
2) through positioning fixture 2 thermocouple 3 is fixed in the ad-hoc location of constant volume mould 7, is about to its probe and fixedly is suspended in the interior tested melt of constant volume mould 7.
3) the Installation and Debugging temperature acquisition system 4.
4) meter ladle 1 is carried out preheating, the method for preheating is: put meter ladle 1 for a long time in preheating furnace, preheat temperature is controlled between 200 ℃-800 ℃; Meter ladle 1 after the employing preheating takes out the melt sample from crucible, when from crucible, taking a sample, meter ladle 1 stopped 0-10 minute in melt; Thermocouple 3 is measured temperature, and when treating that melt temperature is reduced to the detected temperatures that is suitable for temperature acquisition system 4, in melt cast to constant volume mould 7, this detected temperatures is 500 ℃-900 ℃, and the temperature of said constant volume mould 7 is controlled at-30 ℃-100 ℃.
5) temperature-time data (T-t cooling curve) of tested melt solidifying process is gathered and write down to computer 5 control temperature acquisition systems 4; And computer 5 is handled through the routine analyzer of inherence: set up heat according to the temperature of gathering-time real time data and analyze cooling curve; And this curve is carried out first derivation obtain cooling-rate curves; According to the standard boost line, to the actual characteristic parameter that solidifies of magnesium alloy fused mass: actual initial forming core temperature T
α-n is real, the initial forming core temperature T of actual eutectic
Eu-n is real, actual eutectic growth temperature T
Eu-g is real, the actual end temp T that solidifies
S is real, actual eutectic growth time t
Eu-g is realWith the actual concluding time t that solidifies
S is realDemarcate, specifically see shown in Figure 3.
6) plan obtains the standard analysis of alloy to computer 5 and the standard of solidified structure is solidified characteristic parameter: the initial forming core temperature T of standard by transferring in the cast magnesium alloy database 6
α-n mark, the initial forming core temperature T of standard eutectic
The eu-n mark, standard eutectic growth temperature T
Eu-g Mark, standard solidifies end temp T
The s mark, standard eutectic growth time t
The eu-g markSolidify concluding time t with standard
The s mark, and it actual characteristic parameter that solidifies with tested melt compared: work as T
Eu-n is real>T
The eu-n markThe time, add corresponding alloying element; Work as T
α-n is real<T
α-n markThe time, replenish suitable fining agent; As (t
S is real-t
Eu-g is real)>(t
The s mark-t
The eu-g mark) time, increase the addition of alterant in right amount.
Embodiment through some common cast magnesium alloys is further described the present invention below.
Embodiment 1
Adopt the magnesium alloy of technological process shown in Figure 1 and device molten alloy trade mark WE43, basic operational steps is following:
1, uses 40Kg crucible electrical resistance furnace melting WE43 magnesium alloy, melt is warming up to 760 ℃, thermocouple 3 probes are fixed in the ad-hoc location of constant volume mould 7 through positioning fixture 2.
2, open temperature acquisition system 4, adopt meter ladle 1 from crucible, to take out magnesium liquid, be poured into rapidly in the constant volume mould 7.
3, pass through online composition detection of magnesium alloy and solidified structure control device T to magnesium alloy fused mass
α-n is real, T
Eu-n is real, T
Eu-g is real, T
S is realAnd corresponding t
α-n is real, t
Eu-n is real, t
Eu-g is real, t
S is realDemarcate.
4, call standard T in the cast magnesium alloy database 6
α-n mark, T
The eu-n mark, T
The eu-g mark, T
The s mark, t
The eu-g markAnd t
The s mark, through relatively finding T
Eu-n is real>T
The eu-n mark, then add 1.7Kg Mg-Y intermediate alloy.
Replenishing the forward and backward WE43 magnesium alloy solidification of Mg-Y intermediate alloy organizes respectively like Fig. 4 (a) with (b).
Embodiment 2
Adopt the magnesium alloy of technological process shown in Figure 1 and device molten alloy trade mark AZ31, basic operational steps is following:
1, uses 4Kg crucible electrical resistance furnace melting AZ31 magnesium alloy, melt is warming up to 740 ℃, thermocouple 3 probes are fixed in the ad-hoc location of constant volume mould 7 through positioning fixture 2.
2, open temperature acquisition system 4, adopt meter ladle 1 from crucible, to take out magnesium liquid,, treat to be poured into rapidly in the constant volume mould 7 when it reduces to 720 ℃ through thermocouple 3 thermometrics.
3, pass through online composition detection of magnesium alloy and solidified structure control device T to magnesium alloy fused mass
α-n is real, T
Eu-n is real, T
Eu-g is real, T
S is realAnd corresponding t
α-n is real, t
Eu-n is real, t
Eu-g is real, t
S is realDemarcate.
4, call standard T in the cast magnesium alloy database 6
α-n mark, T
The eu-n mark, T
The eu-g mark, T
The s mark, t
The eu-g markAnd t
The s mark, through relatively finding (t
Eu-g is real-t
S is real)<(t
The eu-g mark-t
The s mark), the pure Al that suitably replenishes 0.02Kg is with adjustment eutectic structure content.
The solidified structure that replenishes the forward and backward AZ31 magnesium alloy of pure Al is respectively like Fig. 5 (a) with (b).
Embodiment 3
Adopt the magnesium alloy of technological process shown in Figure 1 and device molten alloy trade mark WE54, basic operational steps is following:
1, uses 200Kg crucible electrical resistance furnace melting WE54 magnesium alloy, melt is warming up to 780 ℃, thermocouple 3 probes are fixed in the ad-hoc location of constant volume mould 7 through positioning fixture 2.
2, open temperature acquisition system 4, adopt meter ladle 1 from crucible, to take out magnesium liquid,, treat to be poured into rapidly in the constant volume mould 7 when it reduces to 760 ℃ through thermocouple 3 thermometrics.
3, pass through online composition detection of magnesium alloy and solidified structure control device T to magnesium alloy fused mass
α-n is real, T
Eu-n is real, T
Eu-g is real, T
S is realAnd corresponding t
α-n is real, t
Eu-n is real, t
Eu-g is real, t
S is realDemarcate.
4, call standard T in the cast magnesium alloy database 6
α-n mark, T
The eu-n mark, T
The eu-g mark, T
The s mark, t
The eu-g markAnd t
The s mark, through relatively finding T
α-n is real<T
α-n mark, suitably replenish 0.4Kg Mg-Zr intermediate alloy, increase the content of Zr in the melt.
The solidified structure that replenishes the forward and backward WE54 magnesium alloy of Mg-Zr intermediate alloy is respectively like Fig. 6 (a) with (b).
The present invention is suitable for containing the zirconium series magnesium alloy and the online composition detection that do not contain the zirconium series magnesium alloy, like: AZ series, ZK is serial, AM is serial and MgRE series etc.