US2149891A - Slag ladle - Google Patents

Description

W. c. KITTO SLAG LADLE March 7, 1939.

' Filed Aug 10,1938

ATTORNEYS.

Patented Mar. 7, 1939 warren s'rA'rEs t nsel PAT E NT @FFE Q SLAG LADLE' Application August 10,

4 Claims.

My'invention-is concerned with slag ladies-or pots-which are formed of cast ferrous metal and are employedfor transporting and handling slag producedduring'the manufacture of steel.

Normally such ladles are suspended in cranes orslag cars by. means of trunnions o-r brackets integrally formed-upon the-wall of the ladle near its top, from which it is evident that a ladle, when loaded, is subjected to severe mechanical stresses at a few localized points. Also under prevailing practice, slag ladles have no refractory lining, sothat molten slag is poured directly in upon the metallic shell or wall of the ladle and subjects it to extremely broad temperature differentials, which not only accentuate the ill effects of the severe mechanical stresses encountered in the method of support, but also create problems due to expansion and contraction.

Under such operating conditions, it has been found that cast iron may not be employed satisfactorily for the ladle as a whole, a ladle so formed being too brittle and'stiif to long sustain rough handling upon trunnion or bracket supports, especially when subjected tohigh temperature differentials. Cast steel has proven more durable under the severe shocks encountered, and is largely used.

But, although cast steel forms a stronger, more durable ladle, its employment is attended with one potent difficulty. (Dccasionally when slag is run into a ladle, some molten steel, which throughout the specification I shall call.slag steel, isentrained and. carried along. This slag steel, being heavier than slag, collects at the bottomof the ladle, and, since frequently considerable time passes before the ladle is emptied, the slag steel cools and solidifies upon the bottom of theladle. It is well known that if slag steel solidifies upon the bottom of a cast steel ladle, the two bodies evince great physical afiinity for one another and the slag steel so tenaciously freezes to the cast steel that its removal is attended with considerable difficulty and expense. Thus such practices are used as inverting the ladle, cutting a ring in its bottom, and dropping an ingot or other heavy weight on the center of the ring" to knock out the center and the slag steel sticker attached to it. At times the ladle is completely ruined. Upon the other hand, if slag steel solidifies upon the bottom of a cast iron ladle, the two metallic bodies evince little or no affinity for one another, and ladles formed from such material, although brittle and liable to break, are not hampered with the difficult problem just discussed.

1938', .Serial N; 224,083;

In-thepastl it has been the prevailing practice to construct slag ladles entirely from one material, either cast-iron or cast steel. Generally such ladles are made in one large integral casting, although sectional ladles of. one material have been proposed in an attempt to combat problems raised-by excessive expansion andcontraction; From the discussion above, it is obvious that" ladlesc formedfrom' either cast iron or cast steel aloneare in oneway or. another peculiarly unsatisfactory.

It-isthe object of my invention to provide a slag ladle constructed compositely of cast iron andlcast steel to the end that the detrimental properties: of each, when used alone, are supplanted by the beneficial properties of the other.

I have found that. a slag ladle having a cast steeLwallsection of any. useful slag. ladle shape and a detachable cast iron bottomof receptacular shape-ably accomplishes this stated object. Supporting trunnions or brackets are always attached to the wall'portion of aladle near its top. Also, the more severe eifects of hightemperature differentials are felt in the wall portion. Acoordingly, for the wall portion where the major strains are felt and borne, I employ cast steel. The bottom of a ladle, on the other hand, bears directly few of the jarring mechanical stresses due to support, its chief function being merely tosupport the-static load of slag above it. Also the temperature differentials have markedly less effects uponthe bottom, especially when it is more or less spherical inshape. Accordingly, I use cast iron-for this bottomportion without danger of its breaking; Moreover, since the ill effects from slag steel manifest themselves in the bottom of a. ladle, by'making the ladle bottom of cast iron and of receptacular shape, I provide for slag steel a reservoir for which it has no detrimental affinity; and entirely eliminate any freezing of slag steel onto the strong cast steel walls. My present embodiment of this invention is disclosed.-irrtheaccompanying drawing of which Fig; 1 isa vertical view ofa slagladle, partly in elevation and partlyin' section, and showing a supporting yokein place; and Fig. 2 is a detailed viewofthemannerin which-the cast steel wall and cast iron bottom are coupled together.

As illustrated in Fig. l, in the upper part of my slag ladle there is a cast steel wall section I which roughly resembles a truncated cone, although it is apparent that the exact form of wall section I is by no means essential to my invention. So long as it functions properly, it may wall I.

take any of the useful shapes, circular, fluted, or otherwise, used for the upperparts of slag ladles. Two diametrically opposed trunnions 2 integral- 1y project from the outside of wall section I near its top, so that the ladle may be suspended from a crane (not shown). Somewhat lower down, several spaced brackets 3 integrally project from the outside of wall section I and function as feet by means of which a yoke 4 of a ladle car (not shown) supports the slag ladle, such yoke being provided with trunnions 5 at its sides for engagement with the car.

A cast iron bottom 6 is detachably coupled to.

cast steel wall I, preferably in the manner shown to enlarged scale in Fig. 2. As there shown, a plurality of spaced lugs I project integrally from the outside of cast steel wall section I, and a plurality of opposing lugs 8 project integrally.

from the outside of cast iron bottom 6. Bolts 9 pass through holes I and II in lugs I and 8, respectively, and are held in place ,by nuts I2 which are turned upon bolts 9 until cast iron bottom 6 is drawn tightly up against cast steel A face portion I3 of the upper edge of cast iron bottom 6 is machined down and an opposing face portion I I of the lower edge of the cast steel wall I is so machined that, when nuts I2 are turned up, there is formed between wall I and bottom 6 a joint sufficiently tight to withstand any outward pressure of molten slag. 7

Since, under the broad temperature differentials encountered, cast steel wall section I and cast iron bottom 6 expand and contract through materiallydiiferent distances, there is in practice some relative movement between the abut- V ting faces I3 and I4. To compensate for this, faces I l and I3 of wall section I and bottom 6, respectively, are at all points parallel to the plane passing through the lower face I of lugs 8, and, since the confined surfaces I3 and I5 of bottom 6 are thus parallel, bottom 6 may freely move outward or inward with respect to wall section I. slightly larger than bolts 9 to accommodate this movement, and there is some clearance. I8 between the remaining edge portions of wall I and bottom 6. Obviously, other equivalent means may be employed to couple together wall I and bottom 6, the exact means being immaterial so long as it supports bottom 6, creates a sufficiently tight joint to resist outward pressure of the slag, and. allows some relative movement between said wall and bottom.

The advantages inherent in my composite slag ladle may readily be appreciated. In the first place, cast steel is utilized in the wall section of the ladle where its toughness and durability are most needed, for it is this wall which, through its integral trunnions and feet, must absorb all the shearing and other jarring stresses incident to rough handling upon cranes or cars. Cast iron is so utilized in my ladle that it is insulated from this rough treatment, being confined to the bottom of the ladle where its sole supporting function is to uphold the static weight of slag above it. It is true that this bottom is supported by means of integral lugs, but these lugs may beas numerous as desired and, more- Holes I0 and II in lugs I and 8 are over, the stresses exerted upon them are relatively constant due to the upward pressure of nut I2, and are different from the jarring ones which occur when the ladle is picked up by a crane or dropped into a trunnion yoke.

.Upon the other hand cast iron is utilized in the receptacular bottom, where its lack of affinity for slag steel is most necessary. Either the solidified slagsteel falls out when the slag is dumped, or it may be easily removed with no harm to the ladle. The cast steel wall, being above the zone of solidification of slag steel, is insulated from its detrimental effects, and, if by chance some does reach and freeze upon the wall, it may be easily removed, for it no longer .is frozen within a deep receptacular body but only to a relatively flat wall. Moreover, the fact that bottom '6 is detachable facilitates this removal.

According to the provisions of the patent statutes, I have explained the principle and construction of my invention, and have illustrated and described what I now consider to be its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A slag ladle comprising a side wall section formed of cast steel to withstand service conditions, a bottom section of receptacular shape formed of cast iron to resist the adhesive tendencies of slag steel, and means for detachably connecting said bottom to said wall section whereby the former may readily be separated from the latter to facilitate the removal of solidified slag steel from the ladle.

2. A slag ladle comprising a side wall section formed of cast steel to withstand service conditions, a bottom section of receptacular shape formed of cast iron to resist the adhesive tendencies of slag steel, and means for connecting said bottom to said wall section in such manner that some relative movement between the abutting faces of ,said bottom and said wall section is permitted.

3. A slag ladle comprising a side wall section formed of cast steel to withstand service conditions, 2. bottom section of receptacular shape formed of cast iron to resist the adhesive tendencies of slag steel, and bolts extending through lugsupon said wall section and said bottom whereby said bottom is held tightly against said whereby the former may readily be separated from the latter to facilitate the removal of solidified slag steel from the ladle.

WILLIAM C. KI'I'TO.

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