SE201747C1

SE201747C1 -

Info

Publication number: SE201747C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: J S Smart jr Denna uppfinning gaiter en kontinuerlig metaligjutningsmetod. Narmare bestamt avser den en metod air detta slag, vid. vilken en forbattrad yta pa gjutgodset erhalles. Sarskilt avser uppfinningen en. sadan metod, som ger bade forbattrad yta och artdra forbattrade egenskaper hos gjutgodset. Inventor: J S Smart jr This invention provides a continuous metal casting method. More specifically, it refers to a method air this kind, at. which an improved surface of the casting is obtained. In particular, the invention relates to a. such a method, which gives both improved surface and kind of improved properties of the casting.

Ehuru manga kontinuerliga gjutningsmetoder ha foreslagits, liar gjutgods, framstallt enligt dessa aldre metoder, i varierande grad kannetecknats air vissa ytfel och inre fel. Ytfelen hos gjutgods, framstallt •enligt dessa aldre metoder, kunna ha formen av en mangd sma, lateral. ytsprickor, veck, rynkiga omraden, som vanligen besta av sma longitudinella faror mom ett begransat omrade, eller ra, stray yta. Vid somliga metoder kunna ytsprickorna Ni sã djupa, att godset brister i formen. Vid gjutning av legeringar med icke-eutektisk och icke-peritektisk sammansattning kan vidare ytan bli sa rt och stray p. grund av genombrott av en bestandsdel med relativt lag stelningspunkt, att gjutgodset kan fastna i formen och hrytas, di det drages ur densamma. Although many continuous casting methods have been proposed, castings made according to these age methods may to varying degrees have been characterized by certain surface defects and internal defects. The surface defects of castings, produced according to these age methods, can be in the form of a multitude of small, lateral. surface cracks, creases, wrinkled areas, which usually consist of small longitudinal hazards with a limited area, or rough, stray surface. In some methods, the surface cracks can be so deep that the goods break in shape. Furthermore, when casting alloys with non-eutectic and non-peritectic composition, the surface can become sore and stray due to the breakthrough of a component with a relatively low solidification point, that the casting can get stuck in the mold and shrink when it is pulled out of it.

Vidare kunna losta gaser, som frigoras frau den smalta metallen under stelnandet, inneslutas i godset och fororsaka inre defekter. Sadana inneslutningar resultera i allmanhet i porositet, vilken vanligen visar sig som sma halrum, vilka kunna vara val synliga eller mikroskopiska och kunna medfora sprodhet hos godset eller sankning av dess draghallfasthet. Vid vissa air de aldre metoderna kan inneslutningen av gaser resultera i relativt stora haligheter, •och det kan rent av uppkomma en sammanhangande kanal i eller nara gjutstyckets centrum. Man har linge och ivrigt fOrsokt undvika dessa .olagenheter, dock utan framgang. Furthermore, particulate gases released from the molten metal during solidification can be trapped in the goods and cause internal defects. Such inclusions generally result in porosity, which usually manifests itself as small cavities, which can be visible or microscopic and can lead to brittleness of the goods or a decrease in its tensile strength. In some air age methods, the entrapment of gases can result in relatively large cavities, • and a continuous duct may even arise in or near the center of the casting. There have been slight and eager attempts to avoid these illegal units, but without success.

Huvudandanaalet med fdreliggande uppfinning är att avhjalpa ,dessa buster hos den aldre tekniken. The main object of the present invention is to remedy these busts of the prior art.

I stort sett innebar uppfinningen att small metall infOres i den ena anden av en i an- damn. Oppen form, som bar en okyld sektion och en. kyld sektion med hOg varmeledningsformaga, vilka bilda en sokyld zon och en kylzon, som fir fast lokaliserad i forhallande till och omedelbart invid den okylda zonen, varvid vardera zonen omsluter den metal', som finns i dess del av formen.. Det kannetecknande nya är att teraperaturen hos den inre ytan i den okylda zonen ,standigt Mlles hogre an smalttemperaturen och temperaturen hos den inre ytan i kylzonen Wiles lagre an stelningstenaperaturen for den respektive zoner innehallna metallen. Den smalta metallen infOres i den ande av for-men, som bildas air den okylda zonen, i en mangd per tidsenhet, som är tillracklig i forhallande till hastigheten vid metallens utdragning ur formen for att bibehalla ett farrad av small, icke-turbulent metall i for-men bortom det plan i den okylda zonen, som ligger narmast kylzonen och som skar igenom formens beta tvarsnitt och skar dess langdaxel och i vilket metallen forblir fullstandigt small under processen. Metallen i formen Mies stilla i forhallande till formen, dvs. ingen metall drages ur formen, forran atminstone utsidan av metallen i kylzonen anda fran namnda plan bar stelnat till ett skal, som Or tillrackligt tjockt och starkt for att kunna dragas ut intermittent ur f or-men Wan att brista. Under bildandet av detta skal avledes atminstone stiirre delen av det fria och latenta varme, som maste avlagsnas far stelning air den metall, som bildar skalet, snabbt i sidled frau metallen genom kyl- 2 zonens yta tack vare den hoga varmeledningsformagan hos forinvaggarna i kylzonen. Det stelnade skalet soch forekommande icke stelnad metall, som omslutes av detta, drages ur intermittent ur formea genom den ande, som bildas av kylsektionen. Hastigheten och frekvensen for denna intermittenta utdragning av gjutgodset aro sadana, att storre delen av skalet pa det utdragna godset bildas i formen, medan gjutgodset star stilla i denna. Perioderna mellan utdragningstillfallena aro ocksd. sâ avvagda, att metallen forblir fullstandigt smaltflytande i skarningsplanet i den okylda zonen. In general, the invention meant that small metal was introduced into one spirit by one in another. Open form, which carried an uncooled section and one. cooled section with high heat conduction shape, which form a so-cooled zone and a cooling zone, which is fixedly located in relation to and immediately adjacent to the uncooled zone, each zone enclosing the metal present in its part of the mold. that the temperature of the inner surface of the uncooled zone is always slightly higher than the melting temperature and the temperature of the inner surface of the cooling zone while lowering the solidification temperature of the metal contained in the respective zones. The molten metal is introduced into the spirit of the mold formed in the uncooled zone in an amount per unit time which is sufficient in proportion to the rate at which the metal is withdrawn from the mold to maintain a flow of small, non-turbulent metal in the mold. but beyond the plane in the uncooled zone which is closest to the cooling zone and which cuts through the beta cross-section of the mold and cuts its longitudinal axis and in which the metal remains completely small during the process. The metal in the mold Mies still in relation to the mold, ie. no metal is drawn out of the mold, until at least the outside of the metal in the cooling zone spirit from said plane has solidified into a shell, which Or is sufficiently thick and strong to be able to be pulled out intermittently from the form Wan to burst. During the formation of this shell, at least the greater part of the free and latent heat, which must be removed from the solidification of the metal forming the shell, is rapidly dissipated laterally from the metal through the surface of the cooling zone due to the high thermal conductivity of the front walls of the cooling zone. The solidified shell and any non-solidified metal enclosed therewith are intermittently drawn out of the mold by the spirit formed by the cooling section. The speed and frequency of this intermittent extraction of the casting are such that the greater part of the shell of the drawn-out material is formed in the mold, while the casting stands still in it. The periods between the extraction cases are also. so balanced that the metal remains completely melt-floating in the cutting plane in the uncooled zone.

Att leda bort huvuddelen av det fria och latenta varme, som maste bortskaffas, for att skalet skall bildas, langs en vag, soin är parallell med gjutgodsets langd,axel, skulle vara alltfor tidsodande for att vara kominersiellt godtagbart. Vid gjutning av legeringar med icke-eutektisk .och icke-peritektisk sammamattning skulle vidare ett sadant fOrfarande vara alltfor langsamt for att forebygga genombrott av bestandsdelar med lag smaltpunkt till utsidan och stelning darpa. Dessutom skulle uppkomsten av ytsprickor i godset icke avsevart reduceras eller elimineras, om flagon av de i foreghende stycke angivna atgarderna forsummades. Alla dessa atgarder aro nodvandiga i den meningen, att de arc utslagsgivande for uppnaendet av det avsedda resultatet betraffande ytbeskaffenheten vid en kommersiellt anvandbar meted. To dissipate most of the free and latent heat which must be disposed of in order for the shell to form, along a vague, soin is parallel to the length, axis of the cast, would be too time-consuming to be commercially acceptable. Furthermore, when casting alloys with non-eutectic and non-peritectic matting, such a process would be too slow to prevent breakthrough of components with a low melting point to the outside and solidification to drip. In addition, the appearance of surface cracks in the goods would not be significantly reduced or eliminated if the flakes of the measures specified in the previous paragraph were neglected. All these measures are necessary in the sense that they are decisive for the attainment of the intended result concerning the surface condition of a commercially usable method.

Vid gjutning av icke-eutektiska och jokeperitektiska legeringar, dvs. sadana, has vilka smaltpunkt och stelningspunkt icke samraanfalla, och sarskilt da skillnaden mellan smaltpunkt och stelningspunkt är stor, har det visat sig, att skalet, liven ,om det är tillrackligt starkt for att kunna dragas ur for-men, kan innehalla interdendritiska kanaler, genom vilka bestandsdelar med lag smallpunkt kunna tranga ut till gjutgodsets utsida genom kapillarverkan ,och stelna utanpa skalet. Denna utsiindring och stelning av bestandsdelar med lag ,smaltpunkt, sarskilt sadana, som i fast form aro hardare an gjutgodsets grundmassa, ge godset en IA, stray yta och kunna leda till, att godset fastnar i formen. I sa fall kan godset brista pa grund av den spanning, som erfordras fOr utdragningen, eller kan formen brytas solider, sal.- skilt mu den är fra.mstalld av sprott material, sasom gmfit. When casting non-eutectic and joke architectural alloys, ie. such that the melting point and solidification point do not coincide, and especially since the difference between the melting point and the solidification point is large, it has been found that the shell, the waist, if it is strong enough to be pulled out of the mold, may contain interdendritic channels, through which constituents with a low point can penetrate to the outside of the casting by capillary action, and solidify on the outside of the shell. This separation and solidification of constituents with layers, melting points, especially those which in solid form are harder than the matrix of the casting, give the casting an IA, a straight surface and can lead to the casting sticking in the mold. In this case, the goods may rupture due to the stress required for extraction, or the mold may break solidly, especially if it is made of brittle material, such as gmfit.

Sadan uttrangning och clarav foljande stray yta pa gjutgods av icke-eutektiska och icke-peritektiska legeringar elimineras praktiskt taget fullstandigt genom att metallen halles stilla i en form med en kylsektion, som har hog varmeIedningsformaga, och kyles snabbt i kylsektionen, tills temperaturen hos atminstone utsidan av skalet är lagre an den. lagsta stelningspunkteri for nagon av legeringens bestandsdelar, som i fast form är hardare an gjutgodsets grundinassa. For uppnaende av basta resultat kyles denna yttre yta ned under stelningspunkten for den bestandsdel, som har den lagsta stelningspunkten, oavsett Mrdheten. En sadan kylning bringar snabbt metallen i de interdendritiska kanalerna ,att stelna och bilda ett skal, som am ogenomtrangligt for de lagsmaltande bestandsdelarna, innan dessa kunna tranga ut till skalets utsida. Darefter Mlles skalets utsida under denna temp eratur under stelnandet av kvarvarande smalt metall, som o,mslutes av skalet. Such protrusion and clear resulting surface on castings of non-eutectic and non-architectural alloys are practically completely eliminated by holding the metal still in a mold with a cooling section having a high thermal conductivity and cooling rapidly in the cooling section until the temperature of at least the outside of the shell is lower than that. the lowest solidification point for any of the components of the alloy, which in solid form is harder than the base of the casting. To achieve the best results, this outer surface is cooled below the solidification point of the component which has the lowest solidification point, regardless of the hardness. Such cooling rapidly causes the metal in the interdendritic channels to solidify and form a shell which is impermeable to the law-melting constituents before they can penetrate to the outside of the shell. Then the outside of the shell is below this temperature during the solidification of the remaining narrow metal, which is enclosed by the shell.

Vid utovning .av metoden fOr erhallande av forbattrade resultat i fraga om slat yta och fOr reducering eller eliminering ,av ra ytbeskaffenhet pa grund av uttrangning, dd. det ar fraga om icke-eutektiska och icke-peritektiska legeringar, stales formen foretradesvis vertikalt med den okylda zonen hogst och kylzonen lagst. Det lampligaste är att anvanda en stationar form, och draga ut gjutgodset intermittent ur denna. En annan foredragen atgard am att avvaga hastigheten och frekvensen for metallens utdragning ur for-men pa sadant salt, att praktiskt taget hela skalet pa den utdragna metallen bildas i formen, medan metallen starsstilla i denna. Den vid varje tillfalle utdragna langden far icke vara stOrre an omkring 50 mm. Battre am att begransa den utdragna langden till 25 mm, och det basta am att icke draga ut mer an omkring 13 mm varje gang. Utdragningshastigheten .skall emellertid vara sa hog som na8jligt. When practicing the method for obtaining improved results in the matter of smooth surface and for reducing or eliminating, of raw surface condition due to erosion, dd. in the case of non-eutectic and non-peritectic alloys, the shape is preferably stored vertically with the uncooled zone at the highest and the cooling zone at the lowest. The most convenient is to use a stationary mold, and pull the casting material intermittently out of it. Another preferred method is to balance the speed and frequency of the metal being extracted from the mold on such a salt that virtually the entire shell of the extracted metal is formed in the mold while the metal is still in it. The length extended in each case must not be greater than about 50 mm. It is better to limit the extended length to 25 mm, and it is best not to pull out more than about 13 mm each time. However, the extraction speed should be as high as possible.

Vid metodens utovning fOr erhallande av ytterligare fordelar, som besta i reducering eller undvikande av gasinneslutning i gjutgodset, aro de fiesta av de avail angivna atgarderna nodvandiga. Salunda ãr det nOdvandigt, att formen star vertikalt med den okylda zonen overst for att lata frigjorda gaser avgà uplift fran den stelnande metallen. Foretradesvis halles formen stilla, dvs. stationar i forhallande till jorden, .och metallen .drages ut ur densamma intermittent. For uppnaende av namnda fOrdel är det ocksa nodvandigt, att varje utdragningssteg joke är langre an omkring 50 mm, och att perioden mellan tvá efter varandra fOljande utdragningar, di alltsa metallen i formen star •stilla, ar sa avvagd, att ingen smaltflytande metall finns under skiljeplanet mellan den okylda sektionen och kylsektionen till storre ,djup an formrummets st8rsta tvarsnittsdimension och att smaltflytande metall endast finns ovanfor det 3 angivna plan, som skar den okylda zonens langdaxel. Foretradesvis bor utdragningen icke vara storre an 25 mm varje ging, och heist bor den icke overstiga 13 mm. Detta Virfarande sakerstaller avgangen av de frigjorda gaserna, som kunna stiga upp genom den smaltflytande metallen. In the practice of the method for obtaining additional benefits, such as consisting of reducing or avoiding gas entrapment in the casting, most of the measures stated are necessary. Thus, it is necessary for the mold to stand vertically with the uncooled zone at the top to allow released gases to escape uplift from the solidifying metal. Preferably the mold is kept still, i.e. stations in relation to the earth, .and the metal .drawn out of the same intermittently. In order to obtain the said advantage, it is also necessary that each extraction step joke is longer than about 50 mm, and that the period between two successive extractions, in which all the metal in the mold stands still, is so balanced that no molten metal is present below the dividing plane between the uncooled section and the cooling section to a larger, depth greater than the largest cross-sectional dimension of the mold space and that molten liquid metal is only above the indicated plane, which intersects the longitudinal axis of the uncooled zone. Preferably, the elongation should not be greater than 25 mm each, and it should not exceed 13 mm. This process slows down the release of the released gases, which can rise through the molten metal.

Den smalta metallen kan inforas i formen ph godtyckligt satt. Saledes kan exempelvis formen vara fastgjord vid bottnen av en smaltuan fran vilken metallen rinner direkt ned I formen, sa att en pelare av smaltflytande metall bildas fran ,det stelnande godset upp till den fria metallytan i ugnen. Ett sadant inforande av metallen i formen fororsakar ingen turbulens i formen. Icke heller har metallen nagon fri yta i formen. Inforande av metallen pa sadant satt, att den har en fri yta i formen, kan emellertid ocksa praktiseras. Metallen kan exempelvis ledas in i formen genom ett r6r eller en yttre led-fling, som utmynnar i formen Vid, ovanfor eller nedanfor ytan av den smaltflytande metallen dari, eller ocksa kan metallen inforas som en fritt fallande strom. The molten metal can be introduced into the form ph arbitrarily set. Thus, for example, the mold may be attached to the bottom of a smeltuan from which the metal flows directly into the mold, so that a column of smalt liquid metal is formed from, the solidifying material up to the free metal surface of the furnace. Such insertion of the metal into the mold does not cause turbulence in the mold. Nor does the metal have any free surface in the mold. However, the introduction of the metal in such a way that it has a free surface in the mold can also be practiced. The metal can, for example, be led into the mold through a tube or an outer hinge flap, which opens into the mold Vid, above or below the surface of the melt-liquid metal therein, or the metal can also be introduced as a free-falling stream.

Forfarandet med en fri metallyta i formen an att foredraga fOr gjutgods med relativt stor tvarsnittsarea, sarskilt vid massive profiler, dar tvarsnittsareans minsta dimension overstiger 75 mm. Vid anvandning av en fritt fallande strom är det viktigt, att den smalta metallen infores i formen i tillracklig mangd per tidsenhet i forhallande till hastigheten vid metallens utdragning ur formen for att med sakerhet uppratthalla ett bad av smaltflytande metall ovanpa den stelnande metallen av tillrackligt djup for att dampa den turbulens, som fororsakas av den fallande strommen, och saledes uppratthalla ett turbulensfritt tillstand hos metallen i det omrade, dar metallen borjar stelna. Ora badet av smalt metall ar alltfor grunt i forhallande till f allhajden, kan turbulensen hos den inkommande metallen na ned till den stelnande metallen och fOrorsaka Adana fel som veck, krusning, kallstank och liknande pa gjutgodsets yta. Turbulent r8relse i detta omrade ,skall alltsa. undvikas, daremot kan laminar rorelse fa f8rekomma och i vissa fall vara Onskvard. The process with a free metal surface in the mold is preferable to castings with a relatively large cross-sectional area, especially in the case of solid profiles, where the minimum dimension of the cross-sectional area exceeds 75 mm. When using a free-falling stream, it is important that the molten metal be introduced into the mold in a sufficient amount per unit of time relative to the rate at which the metal is withdrawn from the mold to securely maintain a bath of molten metal on top of the solidifying metal of sufficient depth for to vaporize the turbulence caused by the falling current, and thus maintain a turbulence-free state of the metal in the area where the metal begins to solidify. If the bath of narrow metal is too shallow in relation to the overall height, the turbulence of the incoming metal can reach down to the solidifying metal and cause Adana defects such as creases, ripples, cold stench and the like on the surface of the casting. Turbulent movement in this area, then. avoided, however, laminar motion may occur and in some cases be Onskvard.

Metoden är tillamplig pa alla metaller och legeringar vid gjutning av massive eller ihaliga, runda eller flersidiga profiler. Metoden enligt uppfinningen an hogst .effektiv vid gjutning av koppar och legeringar pa kopparbas, t. ex. segpolad koppar, koppar med lag syrehalt, dari inbegripet syrefri koppar, och fosforhaltig, deoxiderad koppar, massing, brons och liknande. The method is applicable to all metals and alloys when casting solid or hollow, round or multi-sided profiles. The method according to the invention is highly effective in casting copper and alloys on copper base, e.g. toughened copper, copper with low oxygen content, including oxygen-free copper, and phosphorus-containing, deoxidized copper, pulp, bronze and the like.

Utmarkta resultat ha uppnalts med kopparbaslegeringar, som innehalla tenn eller tenn och bly. Hittills har det icke varit mop ligt att gjuta sadana legeringar kontinuerligt utan att fit ra och stray yta, och detta har varit sarskilt framtr5.dande vid kopparbaslegeringar med minst 4 % tenn. Enligt foreliggande metod kunna sadana legeringar gjutas med slat yta utan sprickor tack vane snabb kylning av skalets utsida ned under stelningspunkten for de harda, tennrika bestandsdelarna. Basta ytbeskaffenhet erhalles emellertid genom snabb kylning ned under stelningspunkten for den bestandsdel, som har den lagsta stelningspunkten, vilken hos kopparbaslegeringar med bade bly ,och tenn är en mjuk, blyrik bestandsdel, varvid dock langre stillestandsperioder fordras. De i denna beskrivning och i patentanspraken asyftade legeringarna innefatta metallblandningar, i vilka bestandsdelarna kunna fullstandigt blandas med varandra i smaltflytande tillstand, saval som metallblandningar, vilkas bestandsdelar icke kunna blandas i detta tillstand. Excellent results have been achieved with copper base alloys, which contain tin or tin and lead. Until now, it has not been possible to cast such alloys continuously without grinding and straightening the surface, and this has been particularly evident in copper base alloys with at least 4% tin. According to the present method, such alloys can be cast with a smooth surface without cracks thanks to the habit of rapid cooling of the outside of the shell down below the solidification point of the hard, tin-rich components. However, the best surface condition is obtained by rapid cooling below the solidification point of the component which has the lowest solidification point, which in copper base alloys with both lead and tin is a soft, lead-rich component, however longer periods of standstill are required. The alloys referred to in this specification and in the patent claims comprise metal mixtures in which the constituents can be completely mixed with each other in the melt-liquid state, as well as metal mixtures, the constituents of which cannot be mixed in this state.

Formen kan framstallas av godtyckligt material och like material kuima anvandas i en och samma form. Material med god varmeledningsformaga anvandes till kylsektionen. F8retradesvis Or ytan av den okylda sektionen eller hela dena sektion av ett material, som icke ails eller endast obetydligt vates eller Mises av den smaltflytande metallen. I allmanhet fOredragas grafitformar, sarskilt vid gjutning av koppar eller kopparbaslegeringar, som. inne- hitllamen Oxen. former av nagon lamp- hg metall kunna anvandas. Vid gjutning med en fri metallyta i en grafitform kunna de utsatta inre och yttre vaggarna av den okylda sektionen skyddas med en. keramisk belaggfling eller en utbytbar grafitbelaggning. Alternativt kan denna sektion skyddas med ett inert eller reducerande material, t. ex. kvave, koloxid eller annan reducerande gas, pulvriserad magnesiumoxid, pulvriserad grafit, trakols-, stenkols- ,eller koksstybb och liknande. Vidare kan kylsektionen vara av metall, sarskilt koppar, och den okylda sektionen av grafit eller keramik. Kylzonen kan vara forsedd med en mantel, genom vilken vatten eller annan kylvatska bringas att cirkulera. Kylsektionens hoga varmeledningsformaga astedkommer da snabb varmeavgang itt sidorna fran metallen i denna del av formen. Enligt uppfinning,en, kannetecknas saledes formen av liana vaggar i kylsektionen och stor temperaturgradient i formvaggen just ovanfor denna sektion i den okylda sektionen. The mold can be made of any material and similar materials can be used in one and the same mold. Materials with good thermal conductivity were used for the cooling section. Preferably Or the surface of the uncooled section or the whole of this section of a material which is not ails or only insignificantly wetted or Mises of the molten metal. Graphite molds are generally preferred, especially when casting copper or copper base alloys, such as. inne- hitllamen Oxen. forms of any lamp- hg metal can be used. When casting with a free metal surface in a graphite form, the exposed inner and outer cradles of the uncooled section can be protected with a. ceramic coating or a replaceable graphite coating. Alternatively, this section can be protected with an inert or reducing material, e.g. nitrogen, carbon monoxide or other reducing gas, powdered magnesium oxide, powdered graphite, charcoal, coal or coke stubble and the like. Furthermore, the cooling section may be of metal, especially copper, and the uncooled section of graphite or ceramic. The cooling zone may be provided with a jacket, through which water or other cooling liquid is circulated. The high thermal conductivity shape of the cooling section then provides rapid heat dissipation to the sides of the metal in this part of the mold. According to the invention, one, the shape of the liana rocks in the cooling section and a large temperature gradient in the mold cradle just above this section in the uncooled section can thus be drawn.

Uppfinningen fortydligas ytterligare genom bifogade ritningar och i det fOljande beskrivna exempel. Delta an emellertid endast 4 illustrationssyfte, och uppfinningen är i sin vidaste omfattning lake begransad dartill. Fig. 1 visar schematiskt i vertikalsektion en apparat f Sr utovning av metoden enligt uppfinningen vid gjutning av klena profiler. Fig. 2 visar pa liknande salt en apparat for gjutning air grova profiler. Fig, 3 visar i vertikalsektion en annan form for gjutning av klena profiler, oat fig. 4 visar en sektion langs linjen 4 4 i fig. 3. Fig. 5 visar en vertikaltektion av en form och illustrerar de olika till-stand, som forekomma i formen under metodens utovning. Fig. 6 visar en horisontalsektion air den i fig. 1 visade fon-nen, och fig. 7 och 8 visa pa liknande satt andra formtvarsnitt. Fig. 9 visar ett gjutprov med ytsprickor. Fig. 10 visar .ett gjutprov air samma sammansattning som det i fig. 9 visade men framstallt enligt den har avsedda metoden. Fig. 11 visar ett prov air en icke-eutektisk och icke-peritektisk legering med ra, stray yta. Fig. 12 visar ett prov av samraa legering som det i fig. 11 visade men gjutet enligt foreliggande uppfinning. Fig. 13 visar ett metallprov med gasinneslutning. Fig. 14 visar ett gjutprov air samma sa.mxnansattning som det i fig. 13 visade men gjutet enligt foreliggande uppfinning. Fig. 15 visar en skiva, skuren frau det i fig. 13 visade provet och darefter avbruten. Fore brytningen var skivan delvis genomsagad langs brottlinjen. Fig. 16 visar en skiva, motsvarande den i fig. 15 visade, men skuren fran provet i fig. 14. The invention is further elucidated by the accompanying drawings and in the examples described below. However, it is for illustrative purposes only, and the invention is to a large extent limited to the same purpose. Fig. 1 schematically shows in vertical section an apparatus for practicing the method according to the invention when casting small profiles. Fig. 2 shows on a similar salt an apparatus for casting air coarse profiles. Fig. 3 shows in vertical section another form of casting of small profiles, while Fig. 4 shows a section along the line 4 4 in Fig. 3. Fig. 5 shows a vertical section of a mold and illustrates the different conditions which occur in the form during the practice of the method. Fig. 6 shows a horizontal section of the source shown in Fig. 1, and Figs. 7 and 8 show in a similar manner other mold cross-sections. Fig. 9 shows a casting sample with surface cracks. Fig. 10 shows a casting sample of the same composition as that shown in Fig. 9 but manufactured according to the method intended. Fig. 11 shows a sample of a non-eutectic and non-peritectic alloy with a straight, straight surface. Fig. 12 shows a sample of the same alloy as that shown in Fig. 11 but cast according to the present invention. Fig. 13 shows a metal sample with gas containment. Fig. 14 shows a casting sample of the same composition as that shown in Fig. 13 but cast according to the present invention. Fig. 15 shows a slice cut from the sample shown in Fig. 13 and then interrupted. Before the break, the disc was partially sawn along the break line. Fig. 16 shows a disc, corresponding to that shown in Fig. 15, but cut from the sample in Fig. 14.

Fig. 1 visar ett aggregat av en smaltugn 1, en form 2 och en anordning 3 f8r intermittent ntdragning av gjutgods 4 ur formen. Formen 2 skjuter upp genom ugnens 1 hot-ten under direkt berOring med den smalta metallen 5 dari. Formen är fastgjord vid ugnsbottn.en medelst gangor 6, som ingripa med motsvarande gangor 7 i ugnsbottnen. Formens nedre del omgives air en kylmantel 8, som foretradesvis an fastgjord pa formen. Vatten eller annat kylmedel halles i cirkulation genom mantel. med lampliga hjalpmedel. Fig. 1 shows an assembly of a narrowing furnace 1, a mold 2 and a device 3 for intermittently withdrawing castings 4 from the mold. The mold 2 protrudes through the heat of the furnace 1 under direct contact with the molten metal 5 dari. The mold is fixed to the oven bottom by means of passages 6, which engage with corresponding passages 7 in the oven bottom. The lower part of the mold is surrounded by a cooling jacket 8, which is preferably attached to the mold. Water or other coolant is kept in circulation through the jacket. with appropriate aids.

Genom kylmanteln uppdelas formen i en okyld zon 9 °ch en kylzon 10. Den. sistnamnda stracker sig vertikalt uppat nagot Over kylmantelns overkant till en linje G—C'. Det exakta laget air denna linje och det plan, som innehaller dens amma, bestammes av varmeIedningsfOrmagan hos formm.aterialet och gjutmetallen, det fria och latenta varmet hos gjutmetalten, kylmantelns kapacitet i fOrhallande till formens tvarsnitt, den period, under vilken metallen star stilla i formen, och hastigheten och frekvensen for gjutgodsets intermittenta utdragning. Planet genom linjen C—C' är det lagsta plan, 1 vilket me- tallen är heist smaltflytande under gjutningsprocessen. Through the cooling jacket, the mold is divided into an uncooled zone 9 ° and a cooling zone 10. It. the latter extends vertically upwards slightly above the upper edge of the cooling jacket to a line G — C '. The exact layer of this line and the plane containing its breast are determined by the thermal conductivity of the molding material and the cast metal, the free and latent heat of the cast metal, the capacity of the cooling jacket in relation to the cross section of the mold, the period during which the metal is stationary. the shape, and the speed and frequency of the intermittent extraction of the casting. The plane through the line C — C 'is the lowest plane, 1 which the metal is highly melt-liquid during the casting process.

Gjutgodset 4 drages ut intermittent ur for-men medelst en utdragningsanordning 3, som bestir av rullar 11, air vilka atminstone en drives av en elektrisk motor 12 Over en remtransmission 13. Motorn 12 Si forsedd med en start- och stoppstromstallare 14 fOr att arbeta intermittent. Anordningen 3 kan ocksh innehalla flagon lamplig bromsanordfling, vilken liar representeras av en. bromsback 15, som sarnverkar med en brcmistrumma 16 pa den drivna rullen 11. Bromsbacken dr medelst en havstang 17 och en lank 18 fOrbunden med stromstallaren 14 far att bromsa och snabbt stoppa rullen, da motorn 12 franslas. Stromstallaren 14 kan paverkas manuellt eller fran ett urverk, som automatiskt sinter och bryter strammen till motorn 12. Flera air rullarna 11, eventuellt alla, kunna vara drivna och bromsade. Denna utdragningsanordning Sr endast ett exempel, och vilken annan lamplig anordning som heist kan anvfindas i stallet. For att basta resultat skall erhallas, shall emellertid utdragningsanordningen starta rullarna 11 tiled hog acceleration for att draga ned gjutgodset 4 snabbt under utdragningsperiodeu och sedan bromsa kraftigt, dd. motorn 12 franslas, sã att gjutgodsets rOrelse hastigt stoppas. The casting 4 is pulled out intermittently from the mold by means of a pull-out device 3, which consists of rollers 11, at least one of which is driven by an electric motor 12 via a belt transmission 13. The motor 12 Si is provided with a starting and stopping current switch 14 for working intermittently . The device 3 may also contain a flap-suitable brake device flap, which is represented by a. brake shoe 15, which cooperates with a brake drum 16 on the driven roller 11. The brake shoe thereon by means of a sea rod 17 and a link 18 connected to the power switch 14 is allowed to brake and quickly stop the roller, when the engine 12 is disengaged. The current generator 14 can be actuated manually or from a clockwork, which automatically sints and breaks the current to the motor 12. Several air rollers 11, possibly all, can be driven and braked. This extraction device is only an example, and what other suitable device can be used in the stable. However, in order to obtain the best results, the extraction device should start the rollers 11 at high acceleration to pull down the casting 4 quickly during the extraction period and then brake hard, dd. the motor 12 is clamped so that the movement of the casting is quickly stopped.

Vid utovning av metoden medelst den i fig. 1 visade apparaten halles den smalta metallens yta i ugnen 1 ovanfor formens 2 overkant 19. Da gjutgodset 4 drages ned, rinner den smalta metallen ner i formen, och denna halles sale-des standigt fylld med en metallpelare. Vid denna apparattyp finns ingen fri metallyta i formen, eftersom denna ar fullstandigt fylld. Vidare u.ppkommer ingen turbulens i den smaltflytande metallen i formen, vilket skulle vara fallet, om metallen infordes som en fritt fallande strom. When performing the method by means of the apparatus shown in Fig. 1, the surface of the molten metal is kept in the furnace 1 above the upper edge 19 of the mold 2. When the casting 4 is pulled down, the molten metal flows down into the mold, and this is kept constantly filled with a metal pillars. With this type of appliance, there is no free metal surface in the mold, as it is completely filled. Furthermore, no turbulence occurs in the molten metal in the mold, which would be the case if the metal were introduced as a free-falling stream.

Fig. 2 visar en grafitform, i vilken den smalta metallen Mores pa sadant satt, att den liar en fri yta i formen. Denna anordning Sr avsedd far gjutning av grova profiler. For-men 2, som Sr forsedd med en kylmantel 8, star pa ben 20, som kunna vara placerade i en vattentank 21, vilken star pa ett fundament 22. Sm5.1t metall tillfores formen som en fritt fallande strain 23 fran en tippbar ugn 21 genom en ranna 25. Fig. 2 shows a graphite mold in which the molten metal Mores is placed in such a way that it has a free surface in the mold. This device is intended for casting of coarse profiles. The mold 2, which is provided with a cooling jacket 8, stands on legs 20, which can be placed in a water tank 21, which stands on a foundation 22. Sm5.1t of metal is fed to the mold as a free-falling strain 23 from a tiltable furnace. 21 through a gutter 25.

Den tippbara ugnen kan vara av godtycklig konstruktion. I det visade exemplet Sr den upphangd pa ett stod 27 och kan tip-pas med hjalp av en hydraulisk kolvmotor 28, som Sr forbunden med ugnen medelst en ledtapp 29. Rannan 25 Sr ocksa monterad pa svangbara stad 30 fOr reglering av me- tallens fallhOjd, som bör vara sa liten som mojligt. The tiltable oven can be of any construction. In the example shown, it is suspended from a stand 27 and can be tipped by means of a hydraulic piston motor 28, which is connected to the furnace by means of a pivot pin 29. The gutter 25 is also mounted on a pivotable shaft 30 for adjusting the drop height of the metal. , which should be as small as possible.

Under drift tippas ugnen 24 for att avge smalt metall i en mangd per tidsenhet, som ar tillracklig i forhallande till utdragningen av gjutgodset 4 for att bibehalla ett metallbad 31 i formen 2, vilket ãr tillrackligt djupt for att dampa den turbulens, som f8rorsakas av den fallande strommen 23, och saledes sakerstalla ett turbulensfritt tillstand i den smalta metallen i badets botten, dvs. narmast ovanf or den bojda linje 32, under vilken metallen ar stelnad. During operation, the furnace 24 is tipped to emit narrow metal in an amount per unit time which is sufficient in relation to the extraction of the casting 4 to maintain a metal bath 31 in the mold 2, which is sufficiently deep to vaporize the turbulence caused by the casting. falling stream 23, and thus ensuring a turbulence-free state in the molten metal at the bottom of the bath, i.e. closest above the curved line 32, below which the metal is solidified.

Gjutgodset 4 kan dragas ut intermittent ur formen med hjalp av rullar 11 pa samma salt som vid den i fig. 1 visade apparaten. PA vag till rullarna 11 passerar gjutgodset genom vattentanken 21, som ãr forsedd med en packning 33 av exempelvis gummi. En kapningsanordning (ej visad) kan vara placerad nedanfor rullarna 11 for att kapa den gjutna stangen i onskade langder. Da endera apparaten startas, anbringas en stang mellan rullarna 11 och skjutes upp i formen. DA den fOrst inforda metallen har stelnat, drages denna startstang ned. The casting 4 can be pulled out intermittently from the mold by means of rollers 11 on the same salt as in the apparatus shown in Fig. 1. PA vag to the rollers 11 passes the casting through the water tank 21, which is provided with a gasket 33 of, for example, rubber. A cutting device (not shown) can be placed below the rollers 11 to cut the cast rod to desired lengths. When either device is started, a rod is placed between the rollers 11 and pushed up into the mold. WHEN the first imported metal has solidified, this starting rod is pulled down.

Den i fig. 2 visade apparaten är lamplig for gjutning av grova profiler och sarskilt for gjutning av koppar, i det att hojden av det fria fallet kan regleras i andamal .att minska eller reglera den mangd syre, som absorberas av kopparn, da den faller genom luften. For att minska gjutmetallens beroring med luften eller annan oxiderande gas kan ett skikt av pulvriserat material 34 hallas flytande pa metallen i ugnen 21 och rannau 25 samt pa badet 31 i formen 2. The apparatus shown in Fig. 2 is suitable for casting coarse profiles and in particular for casting copper, in that the height of the free fall can be adjusted in proportion to reduce or regulate the amount of oxygen absorbed by the copper as it falls. through the air. To reduce the contact of the cast metal with the air or other oxidizing gas, a layer of powdered material 34 can be kept floating on the metal in the furnace 21 and rannau 25 and on the bath 31 in the mold 2.

Pet dr att marka, att ett sadant skyddsmaterial pa badet 31 bryter metallstrOmmens 23 fall och saledes bidrager till att minska turbulensen i badet. Saledes kan badets djup minskas i motsvarande grad under bibehallande av lugnet vid badets botten. Da Mr talas om ett metallbad, som är tillrackligt djupt for att sakerstalla det onskade turbulensfria tillstandet, innefattar detta saledes aven ett bad, i vilket en. del av metallen ar ersatt med ett skyddande skikt av fast material. It should be noted that such a protective material on the bath 31 breaks the fall of the metal stream 23 and thus contributes to reducing the turbulence in the bath. Thus, the depth of the bath can be reduced to a corresponding degree while maintaining the calm at the bottom of the bath. Since Mr is talking about a metal bath which is deep enough to satisfy the desired turbulence-free state, this thus also includes a bath in which one. part of the metal is replaced with a protective layer of solid material.

Om pa grund av den smalta metallens temperatur oxidation av utsidan av den okylda sektionen •av en grafitform ocksa erbjuder ett problem, kan denna sektion skyddas medelst en bekladna.d 35 omkring denna del av formen. Ett mellanrum 36 mellan bekladnaden och formen kan ocksa vara fyllt med det skyddande materialet. I stallet f8r den i fig. 2 visade konstruktionen kan formens okylda del innehalla en keramisk insats eller en utbytbar grafitinsats, som skyddar insidan eller bade insidan och utsidan av den na formsektion. Kylsektiorten kan alternativt vara av metall, t. ex. koppar, och den okylda sektionen av formen kan liksom rannan 25 och rummet i ugnen 24 skyddas av en inert eller reducerande gas. Pet är att marka, att konstruktionen enligt fig. 2 ger god isolation och sakerstaller uppratthallandet av en temperatur i formens okylda zon, som ligger Over gjutmetallens smaltpunkt Detta ãr sarskilt fordelaktigt, dar den. okylda formsektionen Or av ett material med god varmeledningsformaga, t. ex. grafit. Om och nar det skulle vara n.odvandigt, kan derma formsektion ocksa tillf8ras varme. If, due to the temperature of the molten metal, oxidation of the outside of the uncooled section of a graphite mold also presents a problem, this section can be protected by a coating around this part of the mold. A gap 36 between the cladding and the mold may also be filled with the protective material. Instead of the construction shown in Fig. 2, the uncooled part of the mold may contain a ceramic insert or a replaceable graphite insert, which protects the inside or both the inside and the outside of the new mold section. The cooling section may alternatively be of metal, e.g. copper, and the uncooled section of the mold, like the gutter 25 and the space in the furnace 24, can be protected by an inert or reducing gas. It should be noted that the construction according to Fig. 2 provides good insulation and ensures that a temperature is maintained in the uncooled zone of the mold, which is above the melting point of the cast metal. This is particularly advantageous where it. uncooled mold section Or of a material with good thermal conductivity, e.g. graphite. If and when necessary, this mold section can also be supplied with heat.

I stallet fOr att metoden utovas pa det i fig. 1 och 2 illustrerade sattet, vid vilket for-men. är stationar, kan formen bibringas framoch Atergaende rorelse for intermittent utdragning av gjutgodset. Salunda kan exempelvis gjutgodset dragas ned kontinuerligt i fOrhallande till en punkt i runirnet och formen samtidigt sankas med gamma hastighet under den period, dá metallen skall sta stilla i formen. Formen fores sedan uppat med samma eller nagon annan hastighet under den period, da metallen drages ur formen. Vid detta fiirfarande liksom vid det i samband med fig. 1 och 2 beskrivna fOrsiggar relativriirelsen av formen och gjutgodset under den intermittenta utdragningen foretradesvis sa snabbt som mojligt, och dessutom stoppas relativrOrelsen vid slutet av utdragssteget sa snabbt som mojligt. Instead of the method being practiced in the manner illustrated in Figs. 1 and 2, in which form. are stations, the mold can be imparted to the reciprocating movement for intermittent extraction of the casting. Thus, for example, the casting can be pulled down continuously in relation to a point in the runic grid and the mold is simultaneously collected at a gamma speed during the period when the metal is to stand still in the mold. The mold is then fed upwards at the same or some other speed during the period when the metal is pulled out of the mold. In this method, as in the one described in connection with Figs. 1 and 2, the relativization of the mold and the casting during the intermittent extraction preferably proceeds as quickly as possible, and in addition the relativization at the end of the extraction step is stopped as quickly as possible.

Oavsett hur gjutgodset drages ut intermittent, har det konstaterats, att foreliggande metod medger en produktion, som Or 20 till 30 % stone an vad som kan uppnas vid en raetod, dar gjutgodset drages ur formen kontinuerligt. Samtidigt vinnas fordelarna av battre ytbeskaffenhet och lure struktur. Irrespective of how the casting is extracted intermittently, it has been found that the present method allows a production which is 20 to 30% stone of what can be achieved in a raw method, where the casting is drawn out of the mold continuously. At the same time, the benefits of better surface condition and clever structure are gained.

Vid metodens utovning med sikte pa forbattrad ytbeskaffenhet hos gjutgodset Or stillestandsperioden mellan efter varandra foljande utdragningsperioder sa Yang, ,att det hinner bildas ett skal, som Or tillrackligt starkt och tjockt for att tala utdragning av gjutgodset utan att brista. Uppfyllandet av detta krav bevisas av den slata ytan pa det ur formen kommande gjutgodset, och i praktiken kan ifragavarande period regleras efter behov med .hansyn till ytbeskaffenheten. Pet ,sa. bildade skalet nar upp till ytan C—C' fig. 5. When applying the method with a view to improving the surface condition of the casting or the standstill period between successive extraction periods, Yang said that a shell has time to be formed which is strong and thick enough to withstand extraction of the casting without rupture. The fulfillment of this requirement is proved by the smooth surface of the casting coming from the mold, and in practice the period in question can be regulated as required with regard to the surface condition. Pet, sa. formed shell reaches up to surface C — C 'Fig. 5.

DA metaller stelnar till skalet 37, sasom visas i fig. 5 med de heldragna, krOkta linjer, som sammanbinda punkterna och punkterna D—D', bOrjar metallen kryrapa. I planet genom punkterna D—D' slapper skalet formen. Under detta plan reduceras kylsektionens kylande verkan pa grund av den 6 samre kontakten mellan skalet ,och formen. Direkt och darfor bast kylkontakt mellan for-men och gjutgodset fOreligger Mom omradet C—D--D'--C', dvs. utmed linjerna C—D i formen. DA metals solidify to the shell 37, as shown in Fig. 5 with the solid, curved lines connecting the points and points D-D ', the metal begins to creep. In the plane through the points D — D ', the shell relaxes the shape. Under this plane, the cooling effect of the cooling section is reduced due to the common contact between the shell and the mold. Direct and therefore cool contact between the mold and the casting is present in the area C – D - D '- C', ie. along the lines C — D in the mold.

Det fOrmodas, att en av de vasentliga fordelarna hos uppfinningen ligger dan, att detta omrade hr sa stort och sâ skarpt avgransat som mOjligt. Vid varje sarskilt tillstand uppnas .en varmebalans mellan formens okylda del och kyldel i ett plan genom punkterna ovanfor vilket all metallen är smaltflytande. Under planet genom punkterna DD' har metallen icke direkt kontakt med for-men. Den direkta och snabba varmeoverfO- ringen Mom omradetmedan metallen star stilla i formen, resulterar i snabb bildning av skalet 37, av vilket den del, som nar upp till planet genom punkterna C—C', fir tillrackligt tjock och stark for att icke brista vid utdragmingen ur formen. Det antages vidare, att detta är grunden till den dubbla fordelen av fkbattrad ytbeskaff en-het ocb. Mgt produktionstempo, som vinnes genom metoden enligt uppfinningen. It is believed that one of the essential advantages of the invention lies in the fact that this area is as large and as sharply demarcated as possible. In each particular condition, a heat balance is achieved between the uncooled part of the mold and the cooling part in a plane through the points above which all the metal is melt-liquid. Below the plane through the points DD ', the metal does not have direct contact with the mold. The direct and rapid heat transfer to the surface while the metal is still in the mold results in the rapid formation of the shell 37, of which the part which reaches the plane through the points C-C 'is sufficiently thick and strong so as not to rupture. the extraction from the mold. It is further believed that this is the basis for the dual benefit of a battered surface condition unit and the like. High production rate, which is gained by the method according to the invention.

Storre delen air det varme, som avledes under skalets stelnande, avgar at sidorna fran metallen genom kylzonens varmeledande vaggar. DO. skalet 37 har blivit tillrackligt tjockt for att medge utdragning utan bristfling, utdrages ett stycke gjutgods, motsvarande lingden •av linjen C—D i fig. 5, och forloppet upprepas. Utdragningen sker i sadant tempo, att storre delen och fSreträdes- irisutsidan av det utdragna gjutgodset bildas som ett skal 37, medal]. metallen star stilla i formen. Most of the heat dissipated during the solidification of the shell emits the sides from the metal through the heat-conducting rocks of the cooling zone. DO. the shell 37 has become sufficiently thick to allow extraction without flaking, a piece of casting, corresponding to the length • of the line C — D in Fig. 5, is pulled out, and the process is repeated. The extraction takes place at such a pace that the larger part and the outside of the extracted casting are formed as a shell 37, medal]. the metal stands still in the mold.

Vid metodens utovning for erhallande av enbart forbattrad ytbeskaffenhet kan standsperioden Tara just tillrackligt fang for bildning av ett skal med erforderlig tjocklek for utdragning och, .da det fir fraga ono_ Miceeutektiska och icke-peritektiska legeringar, tillracklig aven f5r snabb kylning av atminstone det yttersta ytskiktet av skalet till en temperatur, som ligger under stelningspunkten for den eller de hestandsdelar i legeringen, som i fast form aro hardare an gjutgodsets grundmassa. Vid detta forfarande kan smaltflytande metall forekomma i gjutgodsets inre till varje onskat djup Under kylsektionens overkant. Den lagsta nivfi, vid vii-ken smaltflytande metall kan finnas inne i gjutgodset vid ett sadant fOrfarande, heron bland annat pa gjutgodsets dimensioner, kylmantelns 8 totala langd, kylningens intensitet och utstrackning under planet genom punkterna D—D' i formen och Stillestandsperiodens lfingd. In the practice of the method for obtaining only improved surface condition, the stand period Tara can be just sufficient catch for the formation of a shell with the required thickness for extraction and, if it requires ono_ Miceeutectic and non-architectural alloys, sufficient even for rapid cooling of at least the outermost layer. of the shell to a temperature which is below the solidification point of the equine part or parts of the alloy, which in solid form are harder than the matrix of the casting. In this process, liquid metal can be present in the interior of the casting to any desired depth below the upper edge of the cooling section. The lowest level at which molten liquid can be present inside the casting in such a process, including the dimensions of the casting, the total length of the cooling jacket 8, the intensity of cooling and extending below the plane through points D-D 'in the mold and the life of the standstill period.

Vid den stillastaende formen paverkas ut dragningsrorelsens langd av utdragningshastigheten och sarskilt av utdragningens igangsattning och avbrytande, beroende pa gjutgodsets massa. FOr erhallande av den feirbattrade ytbeskaffenheten bor utdragningslangden icke Overstiga omkring 50 mm. Myeket goda resultat erhallas vid en utdragning av hogst 25 mm at &igen, och bfista resultat uppnas vid utdragning av hogst 13 mm at gangen. For uppniende av den forbattrade ytbeskaffenheten fir stillestandsperioden f0- retradesvis sa lang, att ingen smaltflytande metall finns i gjutgodset under gransplanet mellan formens okylda sektion •och. dess kylsektion till ett djup, som är storre an formrummets storsta horisontaldimension. Detta visas i fig. 1, dar ingen smaltflytande metall finns under den med E" betecknade punkten. Mattet 38 frail kylmantelns 8 overkant 39 till punkten E" fir icke storre an formrummets storsta horisontalmatt. Det sistnamnda visas i fig. 6 som innerdiametern 40 av ett formrum med cirkulart tvarsnitt, i fig. 7 som langden 42 av ett rektangulfirt formtvarsnitt och i fig. 8 som ett radialmfitt 43 i en form med cirkulart tvarsnitt och forsedd med en dorn 44 fiir gjutning av en ihalig profil. In the stationary form, the length of the pulling movement is affected by the pull-out speed and in particular by the start-up and interruption of the pull-out, depending on the mass of the casting. To obtain the four-stroke surface condition, the extraction length should not exceed about 50 mm. Very good results are obtained with an extraction of a maximum of 25 mm at a time, and the best results are obtained with an extraction of a maximum of 13 mm at a time. To achieve the improved surface condition for the standstill period f0- respectively so long that no molten liquid metal is present in the casting under the spruce plane between the uncooled section of the mold and. its cooling section to a depth which is greater than the largest horizontal dimension of the mold space. This is shown in Fig. 1, where no melt-liquid metal is present below the point denoted by E ". The mat 38 from the upper edge 39 of the cooling jacket 8 to the point E" is not larger than the largest horizontal mat of the mold space. The latter is shown in Fig. 6 as the inner diameter 40 of a mold space with a circular cross-section, in Fig. 7 as the length 42 of a rectangular-shaped mold cross-section and in Fig. 8 as a radial elm 43 in a mold with a circular cross-section and provided with a mandrel 44 for casting of a hollow profile.

For att den forbattrade ytbeskaffenheten skall erhallas och samtidigt inneslutningen av gaser i gjutgodset skall forebyggas .eller reduceras till ett minimum, aro de i foregaende stycke angivna fOrhallandena nodvandiga, varjamte formen maste vara staende med den okylda zonen Overst. Darvid kan djupet av badet av smaltflytande metall under planet genom punkterna C—C' (fig. 5) regleras genom reglering av stillestandsperiodens langd. Ju grundare badet blir, desto mindre hr tendensen till inneslutning ay gas i det stelnade godset. Praktiskt taget ingen gas inneslutes, om stillestandsperioden är sä lang att den stelnade metallen nar upp till linjen 41. In order to obtain the improved surface condition and at the same time the entrapment of gases in the castings is to be prevented or reduced to a minimum, the conditions specified in the preceding paragraph are necessary, and the shape must be standing with the uncooled zone at the top. In this case, the depth of the bath of molten liquid under the plane through the points C — C '(Fig. 5) can be regulated by regulating the length of the standstill period. The shallower the bath, the less tendency there is to contain gas in the solidified material. Virtually no gas is trapped if the standstill period is so long that the solidified metal reaches up to line 41.

I stallet for de i fig. 1 och 2 visade for-mama kan en form med flera forrnrum. anvandas, sarskilt vid gjutning av klena profiler. En sadan alt ernativ anordning visas i fig. 3 och 4, dar formen 2 har flera hangheter 45, 46 och 47 men kylzonen har endast en gemensam kylmantel 8. Vid denna konstruktion blir planet genom punkterna C—C', ovanf8r vilket all metall i formen ar smaltflytande, icke ett horisontalplan. Oni endast den forbattrade ytbeskaffenheten asyftas vid metodens utovning, kan en liggande form eller en underifran matad staende form med den okylda sektionen under kylsektionen anvandas. Instead of the shapes shown in Figures 1 and 2, a mold with several front compartments can be used. used, especially when casting small profiles. Such an alternative device is shown in Figs. 3 and 4, where the mold 2 has several hangings 45, 46 and 47 but the cooling zone has only one common cooling jacket 8. In this construction the plane becomes through the points C-C ', above which all the metal in the shape is narrow-flowing, not a horizontal plane. If only the improved surface condition is referred to in the practice of the method, a horizontal mold or a standing mold fed from below with the uncooled section below the cooling section can be used.

Exempel I. Kommersiellt ren koppar gots i en apparat liknande den i fig. 1 visade med 7 det undantaget, att gjutgodset drogs ur for-men kontinuerligt med en konstant hastighet av 235 ram per minut En massiv cylindrisk profil med 75 mm diameter framstalldes. Cirkulerande vatten anvandes i kylmanteln 8 .omkring grafitformen 2. Fig. 9 är en fotolitografi av ett stycke av det salunda framstallda gjutgodset. Det torde observeras, att ytan har flera horisontala sprickor. Example I. Commercially pure copper castings in an apparatus similar to that shown in Fig. 1 with the exception that the castings were drawn out of the mold continuously at a constant speed of 235 frames per minute. A solid cylindrical profile with a diameter of 75 mm was produced. Circulating water is used in the cooling jacket 8 around the graphite mold 2. Fig. 9 is a photolithography of a piece of the cast iron thus produced. It should be noted that the surface has several horizontal cracks.

Exempel II. F8rfarandet enligt exempel I upprepades med den skillnaden, att en massiv, cylindrisk stang med 100 mm diameter framstalldes och godset drogs ut intermittent ur den stationara formen 2. Utdragningsperiodens langd var 3 sekunder, och under varje sadan period utdrogs 5 mm. Stillestindsperiodens langd Tar 1 sekund. Fig. 10 visar det sa framstallda gjutgodset, och det torde synas, att ytan är slat och fri fran sprickor. Example II. The procedure of Example I was repeated with the difference that a solid, cylindrical rod with a diameter of 100 mm was produced and the goods were pulled out intermittently from the stationary mold 2. The length of the extraction period was 3 seconds, and during each such period 5 mm was pulled out. Length of standstill period Takes 1 second. Fig. 10 shows the casting so produced, and it should be seen that the surface is smooth and free from cracks.

Exempel III. Forfarandet enligt exempel I upprepades for framstallning av ett ror av en legering, innehallande 88 % koppar, 10 % tenn och 2 % zink. Det framstallda rorets ytterdiameter var 36,2 ram och dess inner-diameter 12,7 mm. Grafitformen hade det tvarsnitt, som visas i fig. 8. Formen kyldes med vatten i kylmanteln, men for dornen 44 forekom ingen vattenkylning. Roret ,drogs ut kontin.uerligt ur den sililla.stdende formen med konstant hastighet av 300 mm per minut. Det sa framstallda rorets yttre yta visas i fig. 11, och av figuren framgar .att ytan ãr rd och stray. Upphdjningarna pa ytan visade sig besta av tennrika bestandsdelar med lag smaltpunkt, vilka voro hardare an. gjutgodsets grundmassa. Massiva stanger, gjutna av samma legering enligt likartat forfarande, uppvisade samma raa och strava yta. Example III. The procedure of Example I was repeated to produce a tube of an alloy containing 88% copper, 10% tin and 2% zinc. The outer diameter of the rudder produced was 36.2 frames and its inner diameter 12.7 mm. The graphite mold had the cross section shown in Fig. 8. The mold was cooled with water in the cooling jacket, but for the mandrel 44 there was no water cooling. The rudder was continuously drawn out of the sililla-standing mold at a constant speed of 300 mm per minute. The outer surface of the tube thus produced is shown in Fig. 11, and the figure shows that the surface is red and straight. The piles on the surface turned out to consist of tin-rich constituents with a low melting point, which were harder than. the matrix of the casting. Solid rods, cast from the same alloy according to a similar procedure, showed the same raw and rough surface.

Exempel IV. Forfarandet enligt exempel I upprepades med den skillnaden, att en massiv cylindrisk stang, 41 mm i diameter, framstalldes ay en legering, liknande den i exempel III namnda, innehallande 90 % koppar och 10 % tenn. I foreliggande fall drogs emellertid gjutgodset intermittent ur den stillastaende formen. Utdragningsperiodens langd var 2 sekunder, och under varje sadan period utdrogs 16 mm. Stillestandsperiodens langd var ocksh 2 sekunder. Under varje stillestandsperiod kyldes utsidan av gjutgodsets skal snabbt ned till en temperatur val under stelningstemperaturen for legeringens yid lagsta temperatur stelnande bestandsdel. Ytan av det sâ framstallda gjutgodset visas i fig. 12, och denna yta är som synes fri fran fe ojamnheter, som framtrada i fig. 11. Exempel V. FOrfarandet enligt exempel I upprepades anyo f8r framstallning av en amnesstang med 57 mm diameter av en legering, innehallande 90 % koppar, 5 % tenn och % bly. Stangen drogs ut kontinuerligt ur den stillastaende formen med en konstant hastighet av 150 mm per minut. Fig. 13 visar brottytan pa. en. ,avbruten provbit av den sa framstallda stangen. .Provbitens centrala del var poros och hade en. fortlopande central halighet. Fig. 15 visar en Iran. stangen ayskuren och sedan avbruten skiva. Godset var porOst oela det visade sig, att den centrala haligheten strackte sig genom provbiten i hela dess Exempel VI. Forfarandet enligt exempel I upprepades med den skillnaden att en. massiv, cylindrisk sta.'ng med 57 nun diameter och bestaende av 90 % koppar och % tenn framstalldes genom intermittent utdragning av gjutgodset ur den stillastaende formen. Utdragningsperioden.s langd var 3 sekunder, och under varje sadan period utdrogs 9 mm. Stillestandsperiodens langd var 1 sekund. Under varje stillestandsperiod kyldes stangens yttre .skal hastigt till en temperatur val under den lagsta stelningstemperaturen for legeringens bestandsdelar. Darvid fOrekom ingen smdltflytande metall i godset mer an omkring 25 mm under kylmantelns overkant, dvs. mattet 38 i fig. 1 var ,omkring 25 mm. Fig. 14 visar en brottyta pa en provbit av den O. framstallda stangen och fig. 16 visar en fran stangen skuren, avbruten skiva. Det är att marka, att gjutgodsets inre del är fri Iran porer och visa]: en. jamn, god struktur. Example IV. The procedure of Example I was repeated with the difference that a solid cylindrical rod, 41 mm in diameter, was made of an alloy similar to that mentioned in Example III, containing 90% copper and 10% tin. In the present case, however, the casting was pulled intermittently from the stationary mold. The length of the extraction period was 2 seconds, and during each such period 16 mm was extended. The length of the standstill period was also 2 seconds. During each standstill period, the outside of the shell of the casting is rapidly cooled to a temperature choice below the solidification temperature of the lowest temperature solidifying component of the alloy. The surface of the casting thus produced is shown in Fig. 12, and this surface is apparently free from any irregularities which appeared in Fig. 11. Example V. The procedure of Example I was repeated for producing a 57 mm diameter amnesic rod from a alloy, containing 90% copper, 5% tin and% lead. The rod was continuously pulled out of the stationary mold at a constant speed of 150 mm per minute. Fig. 13 shows the fracture surface pa. one. , interrupted test piece of the said rod. The central part of the sample was porous and had one. continuous central holiness. Fig. 15 shows an Iran. the rod ayskuren and then interrupted disc. The goods were porOst oela it turned out that the central holiness extended through the test piece throughout its Example VI. The procedure of Example I was repeated with the difference that one. solid, cylindrical rod with 57 nun diameter and consisting of 90% copper and% tin was produced by intermittent extraction of the casting from the stationary mold. The length of the extension period was 3 seconds, and during each such period 9 mm was extended. The length of the standstill period was 1 second. During each standstill period, the outer shell of the rod is rapidly cooled to a temperature choice below the lowest solidification temperature for the alloy components. In this case, no molten metal appeared in the goods more than about 25 mm below the upper edge of the cooling jacket, ie. the mat 38 in Fig. 1 was, about 25 mm. Fig. 14 shows a fractured surface on a sample piece of the rod produced and Fig. 16 shows a disc cut off from the rod. It is to mark, that the inner part of the cast is free Iran pores and show] the. smooth, good structure.

Exempel VII. Forfarandet enligt exempel I upprepades fOr framstallning av en amnesstang med 45 mm diameter och en analys av 98 % koppar, 2 % tenn och 0,25 % fosfor. Stangen drogs ut kontinuerligt ur formen med en hastighet av 140 mm per minut Stingens yta var 1a och stray, sasom visas i fig. 11. Example VII. The procedure of Example I was repeated to produce a 45 mm diameter amnesic rod and an analysis of 98% copper, 2% tin and 0.25% phosphorus. The rod was continuously pulled out of the mold at a speed of 140 mm per minute. The surface of the stitch was 1a and stray, as shown in Fig. 11.

Exempel VIII. En stang av samma dimension ,och sammansattning som i exempel VII framstalldes .enligt foreliggande uppfinning med hjalp av en apparat .av den i fig. 1 visade typen med grafitform. Gjutgodset drogs intermittent ur den. stillastaende formen, varYid utdragningsperiodens langd var 3 sekunder, och under varje sadan period utdrogs 16 mm. Stillestandsperiodens langd var 1 sekund, och saledes uppgiek produktionen till 240 mm per minut. Stangens ytskikt kyldes hastigt under stillestandsperioderna vid en temperatur val under den lagsta stelningstemperaturen for legeringens bestandsdelar, Det erhMlna gjutgodset hade slat, jamn yta, 8. sasom visas i fig. 12. Produktionen var i detta fall 42 % stOrre an i exempel VII. Example VIII. A rod of the same dimension, and composition as in Example VII, was made in accordance with the present invention by means of an apparatus of the type shown in Fig. 1 in graphite form. The casting was pulled out of it intermittently. stationary shape, the length of the extraction period was 3 seconds, and during each such period 16 mm was extended. The length of the standstill period was 1 second, and thus the production amounted to 240 mm per minute. The surface layer of the rod cooled rapidly during the standstill periods at a temperature choice below the lowest solidification temperature for the components of the alloy. The resulting casting had a smooth, even surface, 8. as shown in Fig. 12. The production in this case was 42% larger than in Example VII.

Exempel IX. FOrfarandet enligt exempel VII upprepades for framstallning av en amnesstang med 41 mm diameter ,och en analys av 84 % koppar % tenn, 2 1/2 % bly och 3 1/2 % nickel. Stangen drogs kontinuerligt ur den stillastaende formen med en konstant hastighet av 140 mm per minut. Den erhallna stangen hade en yta, som var t o m annu raare och stravare an i exempel VII. Example IX. The procedure of Example VII was repeated to produce a 41 mm diameter amnesic rod, and an analysis of 84% copper% tin, 2 1/2% lead and 3 1/2% nickel. The rod was continuously pulled out of the stationary mold at a constant speed of 140 mm per minute. The resulting rod had a surface which was even more rigid and stiffer than in Example VII.

Exempel X. Eu stang av samma dimension och sammansattning som i exempel IX framstalldes enligt foreliggande uppf inning med anvandning av en apparat av den i fig. 1 visade typen med grafitform. Gjutgodset drogs ut intermittent ur den stillastaende formen, varvid utdra.gningsperiodens langd var 3 sekunder. Under varje utdragningsperiod utdrogs 12 mm, och produktionen uppgick till 180 mm per minut, da stillestandsperioden var 1 sekund. Stangens ytskikt kyldes hastigt under stillestandsperioderna till en temperatur val under stelningspunkten for de tennrika bestandsdelarna av legeringen men icke under stelningspunkten for de blyrika bestandsdelarna. God-set hade utomordentligt slat, jamn yta ay den kvalitet, som visas i fig. 12. Example X. A rod of the same dimension and composition as in Example IX was prepared according to the present invention using an apparatus of the type shown in Fig. 1 in graphite form. The casting was pulled out intermittently from the stationary mold, the length of the extraction period being 3 seconds. During each extraction period, 12 mm was extracted, and the output was 180 mm per minute, when the standstill period was 1 second. The surface layer of the rod is rapidly cooled during the standstill periods to a temperature choice below the solidification point of the tin-rich constituents of the alloy but not below the solidification point of the lead-rich constituents. The goods set had an exceptionally smooth, even surface of the quality shown in Fig. 12.

Vid utovning av forfarandet i kommersiell skala under flera manader ha olika arbetstempon Iran. 1 sekund utdragning och 4 sekunder stillastaende till 4 sekun.der utdragning och 1 sekund stillastaende prOvats med tillfredsstallande resultat. When practicing the procedure on a commercial scale for several months, have different work tempos Iran. 1 second extension and 4 seconds standstill to 4 seconds. The extension and 1 second standstill were tried with satisfactory results.

Av det foregaende torde framga, att foreliggan.de uppfinning erbjuder en metod for kontinuerlig gjutning av icke-eutektiska och icke-peritektiska legeringar med undvikande av ra. yta, fiirorsakad av bestandsdelar med lag smaltpunkt, som i fast form aro hardare an gjutgodsets huvudmassa och som vid 5.1dre metoder tranga ut och stelna pa godsets yta. Uppfinningen erbjuder °dish en metod fOr gjutning av metaller och legeringar med ingen eller reducerad tendens till uppkomst av ytsprickor. Vidare erbjuder uppfinningen en atgard f8r eliminering av ytfel, som farorsakas av turbulens i den smaltflytande metallen omedelbart fore stelnandet, t. ex. 1 for-mar med en fri metallyta, i vilka den smalta metallen infores som en fritt fallande strom. Uppfinningen anvisar ocksa ett forfarande, genom vilket gjutgods framstalles, vilket har fiirbattrad ytbeskaffenhet och sarntidigt f Orbattrad inre struktur tack vare eliminering eller reducering av inre ,defekter, som . hero pa. inneslutning av gaser, som frigoras ur den smalta metallen, da den stelnar. It will be apparent from the foregoing that the present invention provides a method of continuous casting of non-eutectic and non-peritectural alloys while avoiding raw material. surface, caused by constituents with a low melting point, which in solid form are harder than the main mass of the casting and which in 5.1dre methods push out and solidify on the surface of the goods. The invention offers a method for casting metals and alloys with no or reduced tendency to surface cracks. Furthermore, the invention offers an action for eliminating surface defects which are caused by turbulence in the molten liquid metal immediately, e.g. 1 forms with a free metal surface into which the molten metal is introduced as a free-falling stream. The invention also provides a process by which castings are made which have improved surface condition and at the same time improved internal structure due to the elimination or reduction of internal defects which. hero pa. entrapment of gases, which are released from the molten metal as it solidifies.

Claims

Patent claim:

1., Continuous metal casting method, consisting of small metal infOres in a. in the spirits open form, which has an uncooled section and a. cooled section with high thermal conductivity, whereby the mold is divided into an uncooled zone and a cooling zone immediately adjacent to the uncooled zone with each zone enclosing the metal contained therein, characterized in that the temperature of the inner surface of the uncooled zone is consistently higher than the melting temperature. the temperature has the hard surface in the cooling zone Mlles lower the solidification temperature of the metal contained in the respective zones, that the molten metal is introduced into the end of the mold, as Midas of the uncooled zone, in an amount per unit time, as in relation to the rate in which cast metal is drawn out of the mold, Or sufficient to maintain a bath of molten liquid, turbulence-free metal in the uncooled zone of the mold near a plane between the zones, where the metal remains completely liquid, that the metal in the cooling zone is kept still in relation to the mold , until at least its outer surface, shaved from said plane, here solidified into a shell which is sufficiently thick and strong for tt resist frictional forces between the mold and the shell and. thus allowing the shell to be formed in relation to the mold, without the shell breaking, the shell being healed, by at least the main part of the perceptible and latent heat, which is dissipated, so that the shell solidifies, being diverted from the metal surface through the inner surface of the cooling zone. , that thereafter a. determined length of cast metal is extracted by the second spirit of the mold, that the extraction is stopped, before shells are formed on a larger part of the outer surface of the molten metal moving along said plane into the cooling zone during extraction, and all the stationary the peeling and elongation of cast metal is repeated until a rod of desired length is obtained, the main part of the shell of the elongated casting metal being formed inside the mold, while the metal stands still relative thereto, whereby the surface condition of the casting is improved.

2. A method according to claim 1, characterized in that the cast metal is rapidly withdrawn from the mold, whereby the molten liquid metal is caused to rapidly pass said plane into the cooling zone without scaling on the moving outer surface, and that the extraction movement is stopped, before flake significant scaling has occurred on. said movable surface, whereby substantially the entire shell of the drawn cast metal 9 is formed in the mold, while the metal stands still in relation to it.

3. A method according to claim 1 or 2, characterized in that the molten metal is introduced into the upper part of a standing mold having its uncooled zone in the upper part and the cooling zone in the lower part.

4. A method according to claim 3, characterized in that the mold Hiles is still and the metal is pulled out intermittently therefrom.

5. A method according to claim 4, characterized in that the length of each extraction of cast metal amounts to a maximum of 50 mm, and that the standstill period between the successive extraction periods is so large that no metal in the melt-flowing state is below said plane to a depth, which is larger than the largest horizontal dimension of the mold space, whereby. entrapment of gas in the solidifying metal is reduced.

6. A method according to patent claim 5, characterized in that the length of each extension is at most 13 mm.

7. A method according to any one of claims 3-6, characterized in that a free-falling strain of the molten metal is introduced into the upper part of the mold and in the uncooled zone of the mold a bath of molten liquid of sufficient depth is maintained to vaporize the turbulence. which is caused by the incoming stream of narrow metal, and thus leaves turbulence-free melt-liquid metal in the vicinity of said plane.

8. A method according to any one of claims 3 to 7, characterized in that the molten metal is allowed to form a free surface in the mold, and that its inner and outer surfaces are protected from direct contact with the air.

9. A method according to any one of claims 1-8, characterized in that the metal is an alloy of non-eutectic and non-architectural composition and that the metal is still in relation to the mold, until the temperature of at least the outer surface of the shell is lower than the the solidification temperature for the constituents of the alloy, which in solid form are harder than the matrix of the casting.

10. A method according to claim 9, characterized in that the outer surface of the shell is cooled below the lowest solidification temperature for the components of the alloy.

11. A method according to claim 9 or 10, characterized in that • the metal is an alloy on a copper base and that the mold has a gTafit shape.

Method according to patent claim 11, characterized in that the copper base alloy contains at least 4% tin.

13. A method according to claims 40 and 11, characterized in that the copper base alloys contain tin and lead.

14. A method according to any one of claims 1-8, characterized in that the metal is copper and that the mold is a graphite mold. Requested publications: Other publications: Day, J W, Modern metal production. Walsall 1947, pp. 30-35.