US1915635A - Foundry ladle - Google Patents

Description

Patented June 27, 1933 UNITED STATES PATENT OFFICE GEORGE H. WEIDEMANN'NI5 HORAGE E. KELLEY,OF MIDLAN D, MICHIGAN, ASSIGNOBS T0 TEE DOW OHEMICAL COMPANY OF MIDLAND, MIC HIGAN A COBPORA'IION O]? MIGIHIIGAN roumpmr LA]5LE Applieation flled August a1, 1932. Serial 1\To 631,226.

The p'rcsent invention relates to a ld1e for dipping molten mc tal from a body the1eof and transferring th'esame to a mold 01 other of readily oxidizable metals, such as magnesium and the alloys thereof.

The term magncs1um or magnes1um alloy used herein and in thc appended claims means pure magnesium 01 an alloy thereof containing per cent o1 more cf magnesium.

According to conventional foundry practice, molten mctal is transferred from the melting equipment to the molds by means cf an opcn vessel 01 ladle. Conventiohal ladles for the purpose consist essentially of a;vessel of suitable size t0 hold the molten metal, having a pouring lip atthe rim th areof. In sonne of these a2 skimmer is provided at the pouring lip to prevent floating impurities, such as dross or slag, from running out with the molten metal; in others, the metal is discharged from an opening in the side or bot tom of the ladle. Such ladles may be provided with a handle or mounted on trunnions or supported by a bail. v

When such ladles are used with molten m2lg11esium, they are not wholly satisfactory inasmuch as a number of special Problems arise in connection with the melting, handling, and pouring of such teadily 0Xidi2able metal. F01 example, in the conventioneyl mcthods for melting magnesium, a flux 1s used with the metal in the melting pot; T he flux acts not only tocollect the imf urities from the metal with which it is in contact,

but also to form a protective covcringover the metal which excludes the atmosphere and prevents oxidation or burning. TWO general types of fluxes are so employed. The one type is a semi-fluid mixture composed usually cf molten alkali and alkalinc earth metal salts thickened with alkaline earth metal oxides and fluorides. Theother type is a, highly mobile fused mixti1rc conswting p'rincipally of alkali and alkaline earth metal salts such as sodium chloride and magnesi'um 0 chloride. The specific gravity of the lattier type cf flux is regulated in some instanceaa by the addition of a relatively smallproportion 0f bar1um chloridc, so that the metal floats in the molten mixture and ab thc same time the surface tension cf the flux mixture is such that the top surface of the metal is' more o1 less completely covercd with a film of the molten fluid.

When it is attempted to withdraw molten magnesiutn from a melting pot some flux may bccome entrained with the metal in thc ladle and, if the ladlc be of a conventional type, some cf the entra ined flux will be discharged with the metal into the mold. The known bottom or side pouring spouts or surface skimming attachments of cohvent-ion'al ladles are ineflectivcto retain in the ladle the highly mobile moltcn constitucnts cf. the fluXes owing to their tendency to floW with the metal. The molten mobile fluxes creep or fiow in the intcrface between t-he Walls cf the ladlesnd the body of molten metal theiein anal such crecping is ai'tlecl by the motion of the molten metal as it passes over the surfacc when poured from theladle. Thus it beco1'nes practically impossible to pour a Casting that is frce from flux iyclusions u'sing a conventional type of ladlefor dipping the molten magnesium from a flux covered body thereof.

One cf the objects cf the present invention is t0 provide a ladle suitable for tra-nsferring molt-en magnesium from a flux covered body thcreof to a mold such that it prevents flux 0r other impurities, wh ich may enter the ladle when the molten metal is dipped there- With, from being discharged With thc molten metal. Other objects and advantages will apjuear as the description proceeds. T0 the ac.cofnplishment of the foregoing and relafed ends, the invention, then, c01is ists 0f the apparatus hercin2ifter fully described and part1cularly poihtd out in thc claimg, the annexed drawing and the follow i'ng description setting forth m detail certain means cf c-argying ou't theinvention, such means illustrating, however, but several of the various Ways in which the principle of thc invention may be used.

In said annexed drawingz- Fig. 1 is a vertical central section through our improved ladle. 0ur improved ladle.

In the present invention an open top vessel of suitable capacity is employed which constitutes the body of the ladle. A guard is provided on the upper rim 011 the pouring side which extends over a portion 0f the top of the vessel so that the ladle maybe tilted about its axis in the pouring plane as much 2 is a plan view of as 100 without discharging metal over the 1 flux-contaminated metal from the ladle.

Refer'ring t-o the drawing, 1 is a fluid tight vessel of suitable capacity, 2 is a pouring tube or spout extending downwardly into the vessel at an angle with the wall thereof. Spout 2 is sealed through the liquid tight guard 3 at the top of the vessel, but does not touch the side Walls thereof. A sweep 4 is attached to the outside of the vessel near the rim thereof and diamenricallj opposite t0 the pouring spout while a handle 5 is provided for mampulating the ladler When the capacity 0f thevessel is t00 great for band. manipulation, trunnions may be substituted for the handle. These may be located on the Walls of the vessel as indicated at 6. In some cases ifi may be preferable to employ a handle, as indicated, together with a. bail. The space provided between the inlet end 10 0f the pouring tube 2 and the bottom corner 11 of the vessel is suflicient to permit impurities to gather, sothat they will not be drawn into the A pouring tube when the ladle is tilted uring pouring.

The essential elements of our new and improved ladle comPrise a vessel, a poring tube located at its upper end near the rim 0f the vessel and depending therein towards the bottom and out of cpntact with' the walls thereof and a guard c0vering a portion of the top of said vessel so that metal may be discharged through the pouring spout from the ladle wheri tilted;

The whole of the ladle above' described inay be constructed from anmetal havin a high melting point and which does not al%oy with magnesium. Iron or sjteel is wel1 suited for' the purpose, and the individuallyindicated parts maybe'assembled readily by weld- %)ur improved ladlia may be used in the .following manner .in connection with the transfer of molten magnesiutn from a, flux covered molten body thereof to a mold :The

flux or impurities floating pon the surface -0f molten metal in a melting pot is swept aside by means of.the sweep 4 to expose an area of clean metal in which to submerge and fill the ladle. After filling5 a porti0n of the metal may be poured back into the melting pot so as to rinse out of the pouring spout oxide or other impurities which may collect therein. The molds are then poured promptly, care being taken to stop pouring before the pouring spout becomes uncovered by metal. In this way flux which may be dipped up accidentally with the molten metal in the ducted.

Test 1 A quantity of magnesium alloy consisting of approximately 94,7 per *t:ent magnesium, 5 per cent aluminum and 025 per cent manganese was melted down in a bqtl1 of magnesium chloride-sodium chlor'ide flux. A conventional bottom pouring ladle was therrused to dip metal out of the melting pot by first .brushing aside as much of the flux as possible and then dipping metal eut of the pot from the area exposed. The n1eal was then poured from the ladle into a cylindrical billet mold and allowed t0 solidify. After solidification the'bilkat, weighing approximately 7 0 pounds,was machined to remove the outer skin and then subjected to examinatidn for defects. The machined surface showed a number of holes filled with flux. The billet was then radiographed which showed that there were flux inclusions distribufed throughont the casting. This was further verified by cutting the casting into sections und on visually inspecting these sections flux inclusions previously shown by the radiograph were plainly visible.

Test 2 was machined to remo ve the outer skin and then subjected to the same examinations as in the previ0us test. The result of these observations showed thzit the surface ofthe billet was freefron'1 flux inclusions. The interior Cf the billet, as shoWn by radiographs and by a visual irispection of sectibns cut therefrom, was entirely free Tro m flux inclusions.

Test 3 Using our improved ladle, the fiux was pushed back from the surface 0f the metal in the melting p0t and as bef0re a ladle of 1netal was withdrawn therefrom. A quantity of flux of the same composition as was used in the molting pot was then poured onto the surface 0f the molten metal in the ladle and then a similar billet was cast by pouring the metal from the ladle into the billet mld While the flux remained in the ladle. After casting, the out-side skin of the billet was machined off and then the billet was examined for defects. The machined surface was entirely free from flux holes, and the interior,as examined by the radiograph and by a visual inspection 0f sections cut therefrom, was entirely free frorn fiux inclusions.

These tests show that when sonne flux is inadvertently admitted to our improved ladle the lon,q surface 0f travel over Which such flux must necessarily pass before it can be discharged therefrom prevents the entra'nnnent thereof with the 1nolten metal and so prevents flux inclusions in the casting.

The invention is also especially valuable since any type of impurity that is separable from the metal by gravity, such as oxide o1 finx, which tends t0 accuxnuate either in the butto1n of tho 1a d1e 0r on the metal surface 01' both While tho n1etal is being poured therefromcannot be discharged fro1n the ladle during such an operation. Therefore, our new ladle provides a means 0f preventing simultaneously not only floating impurities, but also settle l impurities from entering the casting'.

This application is a continuatioh in part of our prio1 applicati on Serial N0. 512,908, filod February 52, 1931.

Other modes of applying the principle of 0ur invention may be employed instead of those explained, change being made as regards the 1neans herein disclosed, provided those stated by any of the following claims 01 thcir equivalent be employed.

\Ve therefore particularly point Gut und distinctly claim as 0111 inventionz 1. In a ladle 0f ehe character described, the combination of an open topv vessel,a liquid tight guarcl attached to (he rim thereof and extending part way over the top of said vessel, a tubular subsurface pouring spout sealed through ehe guarded rim of said vasse1 and extending downwardly therein at an angle With the wall thereof.

E2. In a ladle of the character described, the combination 0f an 0pen t0p vessel, a liquid tigh t guard attached to the rim thereof and extending part way over the top 0f said vessel, a tubular snbsurface pouring spout sealed through the guarded Iim of said Vessel and extending downwardly therein at an angle with the Wall thereof, and a sweep attached to the wall of the vessel at a point near the rim and diametrically opposite to said pouring spout.

Signed by us this 24 day of August, 1932.

GEORGE H. WEIDEMANN. HORACE E. KELLEY.

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