US2681260A - Cylinder and liner - Google Patents

Description

June 1954 s. s. KISTLER CYLINDER AND LINER Filed July 27, 1951 f R -wwmq 5 5 Q W on .I A F K Q m y u M .Q 7 m Nv 9w N I- m N m w A Q9 w NW y Q 5 3 h #N m a m 8 Patented June 15, 1954 2,681,260 CYLINDER AND LINER Samuel S. Kistler, West Boylston, Mass, assignor to Norton Company, Worcester, M

ass., a corporation of Massachusetts Application July 27, 1951, Serial No. 238,862

4 Claims.

The invention relates to cylinders and liners, I especially cylinders and liners for internal com (relatively) soft on the outside so that it can be readily machined on the outside.

Other objects will be in part obvious or in part pointed out hereinafter.

The accompanying drawings are illustrative of lustrative. In these drawings Figure 1 is a view partly in side elevation and partly in axial section of such apparatus,

having huts so thereon at one end; the bolts 29 pass through the plates 2! and 28 as Shown. Be-

tween the plates 21 and 28 and held in position by the pressure exerted on the plates by the bolts 29 is a hollow cylinder 3|. Thus is formed a hollow cylindrical mold body rotatable on the axis of the cylindrical inside surface of the body. The plates 21 and 28 and the hollow cylinder 31 can be made of iron or steel.

Secured to the end of the plate 23 by means of bolts 35 is a head 36 on the end of a hollow shaft 37 which extends through a bearing 38 supported by a post 39 connected to the frame I5. I shall not describe the various parts of the bearing 38 as the drawing is clear and such details can be widely varied.

The frame I 5 which as shown may have the shape of a table top can be placed in a vertical position as well as in the horizontal position in which it is shown in Figure 1. To that end a latch 40 slidable in a holder H which is secured to the underside of the frame I5 is engageable with a plate 42 on the top of a post 43 4 frame I5 from further clockwise movement.

When it is desired to place the frame It in a vertical position, the latch 40 is withdrawn by means of its handle 45, the frame is swung counter-clockwise and the operator steps on a plate 46 through which extends a bolt 41 having nuts 48 under the plate 46, the bolt 41 extending also through a block 49 secured to the bracket I3 and being surrounded by a spring 56 under the bolt head 5|, the spring 50 acting to urge the parts into the position shown in Figure l but when the operator steps on the plate 46 the bolt head 5| is lowered and can enter a recess 52 at the end of the frame I'5 whereby releasably to lock the frame I5 in the vertical position.

The hollow mold cylinder 3I may have any suitable liner embodied in a hollow cylindrical member 55, a solid end plate 56 and an end plate 5! having a hole therein concentric with a hole through the circular plate 28. These liner parts 55, 56 and 51 can be made out of any suitable material which is sufiiciently refractory and non-remina is satisfactory and hollow tubular shapes such as the part 55 as well as disc shapes such as the parts 56 and 5? can be readily made out of sintered alumina. Liner parts made in this manner can be ground with diamond grinding wheels to produce true surfaces and then the liner parts can be used over and over again as the casting shrinks away from the part 5-5 in cooling and hence readily comes out. I have however successfully used a paste of 80 parts of fine alumina and 29 parts of ball clay with enough w or to make it workable, the alumina being one sec mesh size and one half 150 mesh size. This can be hand molded in position with a spatula while turning the mold 3i and after drying makes a good mold lining which is destroyed after casting. But when casting cast iron cylinders I can use steel mold liner parts 55, 56 and 5'! because the melting point of steel is considerably higher that of cast iron.

The procedure for making the cylinders and liners may start with placing the frame it in the vertical position, wherefor as will readily be seen the axis of the mold body M will be vertical, whereupon the motor 2% is started and liquid ferrous metal til is poured: into the hollow shaft 3? whereupon it promptly flows into the cylindrical space bounded by the liners 55, 5B and 5"! and the centrifugal force spreads it out in the form of. a hollow cylinder of liquid. Ihe carbide material may be introduced into the mold with, be fore or after the liquid ferrous metal. The carbide material is in the form of, particles (not liquid) and. can be of particle size as large as 8 mesh but may also be smaller.

I prefer sizes between l300 mesh, but. I have found that precipitated carbide particles as fine as 2 microns diameter are very effective. As it is better to form the cylinder or liner in a horizontal position because thereby the component of gravity does not affect the shape, right after pouring the ferrous metal and introducing the carbide material the operator should step on the plate it, thus withdrawing the head i from the recess 52, and should then swing the frame it rapidly to the horizontal position, whereupon the latch to will, automatically loci; it in that position which is shown in Figure l. Rotation of the mold is continued and eventually the metal freezes usually starting at the outside and when the metal til has become a solid piece the motor do is stopped and both mold and piece are allowed to cool whereupon eventually the mold parts can be disassembled.

Optionally I may use further equipment in the process. Referring again to Figure l, a pneumatic vibrator id is secured by means of flexible brackets H to the frame l5 and this is energized by compressed air introduced. by a flexible rubber hose it. To one end of the vibrator id is secured aslideway block it by means of bolts M. A removable slide i having a handle "i6 can be inserted in the slideway block 53 from the right toward the left and when pushed to the extreme position as shown in Figure l a spring-pressed ball as releasably locks the parts together, an abutment 8i pre venting further movement toward the left.

This slide E5 upholds a long T-shaped iron 85 illustrated in cross section in Figure 3 and in side elevation in Figure 1. This T-shaped iron 85 can be welded to the end of the slide '55 both parts being conveniently made of steel. At the left hand or front end of the T iron 85 is a tray 81 which can also be made of steel and welded to the T iron. This tray 81 has holes, not shown, in the bottom thereof, so it constitutes in effect a sieve, the holes being of a size just large enough to pass the parti-les of carbide. This tray 8": is, when using the apparatus just described, filled with carbide material and, when the frame i5 has been swung to the horizontal position, the tray 5, illustrated also in Figure 2, and

interior surface of iron 85, this iron pipe 9% having 8? is inserted in the mold as shown, the slide 15 being inserted in the slideway block it as shown, whereupon the vibrator it is energized and thus the carbide material is slowly sifted onto the the melt 68' which concentrates it at said interior surface whereas the differencein specific gravity of the carbide material and the iron respectively prevent the carbide material from migrating into the interior of the melt 69.

It may also introduce a special atmosphere into the rotating mold, for example an atmosphere of hydrogen, and to that end, as shown in Figures 1 and 3, I secure an iron pipe st to the T a bend 9% with a nipple thereon at the right hand end to which arubber hose 92 can be quickly connected to introduce the desired gas into the rotating mold.

I have found that I can make cylinders and liners of ferrous metal having at the inside surfacea layer of hard carbide bonded together by the ferrous metal using carbide selected from the group consisting of vanadium carbide, titanium carbide, zirconium carbide and mixtures thereof. I can do this Without dispersing the carbide throughout the metal of the cylinder or the liner. For practical purposes it is sufficient if the inside of the cylinder or liner is hard for a depth of from 2lto lothousandths of an inch. The amount of carbide in the interior portion containing the carbide should be between 20% and by volume. It is difficult to pack the carbide particles closer than 75% in the centrifugal field, while 20% by volume appears to be a practical lower limitof concentration for effective resistance to wear.

Vanadium carbide is a compound generally assumed to be V0. However I am not to be held to the correctness of this formula and any true compound of ivanadium and carbon without other elements. in the compound is usable. Similarly titanium carbide is assumed to be TiC and zirconium carbide ZrC and the same provisos apply, namely that I am not to be held to the correctness of these formulae and any true compound of titanium or zirconium and carbon not containing other elements in the compound can be used.

The following table gives the hardness, melting point, and specific gravity of the carbides mentioned and also of pure iron known as ferrite.

Table I Hardness on a sthelKnfotg Nffeltiug aggi g ca e o t c oint Material I a {i f CDegTees agggm n ica e a tor entigrade v Q the slant line W 1 P Iron, ferrite 40 25 1,535 7.35 Iron carbide, cementitc... 1,15%25 l 837 7.4

. 2 520 25 Vanadium, carbide 1 2. 830 5. 4 Titauiumcarbidenh 2,470/100 1 3,140 4.9 Zirconium carbide 1,800/100 1 6.4

The above table shows the great advantage of vanadium, titanium and zirconium carbides over iron carbide for Wear resistance. It should be noted that the hardness of sapphire, which is 9 on Mohs scale, is approximately that of vanadium carbide.

All of the carbides with which I am familiar are soluble in molten iron. The degree of solubility. varies greatly from one carbide to the other, however, and I find that vanadium car.- bide is the least soluble. I can disperse vanadium carbide in molten cast iron or steel and centrifuge the particles to the inner amined microscopically after solidification, show rounded corners and edges and there is some of precipitation Titanium and zirconium carbides mixed into a melt have has proved adequate.

Apparently when the are freely wetted and spread over the molten surface by centrifugal force.

The carbides donot need to be added as such to steel or cast iron but can be trifugal force, e. g., 100 gravity.

A precaution has to be observed in generating the carbide in situ to see that thereis enough carbon in the melt to produce the carbide plus providing the properties of the melt desired.

Instead of mixing the ferro alloys with the melt,

ture of two or all three in the form of metal powder, relatively pure. Such metal powder may be mixed with carbon power or not, depending on the amount of carbon otherwise available.

Example 1 I mixed 4 grams of 200 mesh vanadium carbide with 40 grams of cast iron chips, melted granules of vanadium carbide 1n the cast iron produced by precipitation on cooling, showing that some of the vanadium carbide dissolved but not enough to prevent a satisfactory armoring of the inner surface.

Example 2 iron alloy, known to the trade as NiHard, and 1.6 grams of 2.

produced by precipitation of VC from solution due to the reaction between the added vanadium and carbon in the cast iron.

Example 3 Pellets similar to those in Example 2 were molded but without the vanadium carbide. were placed in a mild steel mold of the dimensions given in Example 1 and melted at 1300 Many vanadium carbide parbe found throughout the mass Example 4 A mold of the same dimensions as in- Example 1 wa heated by induction to 1250 C. and 50 grams of melted gray cast iron poured in. Onto the surface of this rotating molten cast iron was sprinkled 3 grams of 200 mesh vanadium carbide. The atmosphere used was tank hydrogen. On cooling, the vanadium carbide was found to have been thoroughly wetted by the cast iron and to have concentrated in the inner surface of the cylinder. This mold was also rotated at 1200 HP. lvl.

Example 5 Molten cast iron was spun in a mold as in EX- ample 4 but t grams of ferrovanadium was spread on the surface instead of vanadium carbide. On cooling, the inner surface was found to be heavily loaded with fine Vanadium carbide particles produced by reaction of ferrovanadium with the carbon in the cast iron.

Example 6 The procedure followed in Example 4 was used except zirconium carbide was substituted for the vanadium carbide, using a well purified hydrogen atmosphere. On sectioning the cylinder, thezirconium carbide was found well imbedded in the inner surface.

Example 8 A cylinder of mild steel was made with inside dimensions 1 diameter by 1" long. On the inner surface was spread a paste of l grams of 200 mesh vanadium carbide and 1 gram of fine graphite mixed with glycerin. This was rotated at 1200 R. P. M. in an atmosphere of hydrogen and heated by induction to 1250 C. On cooling, it was found that the carbon had fused the inner surface of the cylinder to a depth of 1 to 2 mm. and the vanadium carbide had been imbedded in this layer. The alloy on the inner surface con- .isted mainly of cementite and ferrite.

Example 9 The procedure was followed as in Example 8 only 10.2 grams of 50% ferrovanadium and 1.7 grams of graphite were spread on the inner surface, using glycerin as a vehicle. When heated to 1280 C. and cooled, the inner surface was found to be armor plated to a depth of 1 mm. with vanadium carbide dispersed in iron. Example 1 O Pellets were made by mixing parts by weight of powdered iron with 40 parts of 200 mesh titanium carbide and pressing in a mold at 25 tons per square inch. Ten grams of these pellets were broken up to about 8 mesh size and distributed over the inner surface of a cold cast iron cylinder in a mold rotating at G R. P- M. Using an atmosphere of purified and dried hydrogen, the mold was heated inductively to a temperature of =0 C. and allowed to cool. The iron-titanium carbide pellets were found to have completely disintegrated and the titanium carbide grains to be well distributed and thoroughly imbedded throughout the-inner surface of the cylinder.

Example 11 The procedure was followed as in Example 8 only titanium carbide was substituted for vanadium carbide. With a good hydrogen atmosphere the titanium carbide imbedded satisfactorily in the inner surface of the iron cylinder.

Example 1-2 Example 13 I mixed 30 grams of cast iron chips, 2 grams of titanium shavingsv and 0.6 gram of fine graphite and spread in a cold rotating mold of mild steel like described in Example 1. The speed was 1200 R- P. M. I then inductively heated the mold rapidly to 1300" C. and held between 1300" C. and 1310 C. for six minutes whereupon I turned off the current. The atmosphere was. tank hydrogen. On sectioning, polishing and examining under the microscope, the inner surface was found to contain great numbers of TiC particles, ranging from 2 to 6 icrons, in diameter, to a depth of about a millimeter.

, The atmosphere inwhich the centrifugal forming of a hard inner surface on a metal cylinder is carried out may vary considerably depending on the carbide to be used. For example, burnt gas such as exhaust from a gasoline engine when the carburetor is set for excessive gasoline, or that known to the trade as Endogas is perfectly satisfactory for the introduction of vanadium carbide into the surface. Pure nitrogen, carbon monoxide or mixtures of these gases may also be used, as well as mixtures containing hydrogen, which is an important constituent of the Endogas. When it is desired to use zirconium or titanium carbide, I have found it preferable to use a very carefully dried gas free from any oxygen and I prefer pure hydrogen. The inert gases, such as helium and argon, may be used but precautions necessary to eliminate all oxygen or water vapor are troublesome.

A high vacuum is, under some circumstances, the best atmosphere but its inconvenience dictates that for practical purposes one of the abovenamed. gases should be used. The gases may be introduced through the rubber hose 92 and pipe 90. The various gases mentioned are nonoxidizing.

The advantages of the invention lie in the fact that the manufacturing process is relatively simple and only a small amount of the expensive carbidematerial need be used. All three of these carbides usable in the invention are expen-' sive. Furthermore the major portion of the cylinder or liner made according to my invention has little or none of the carbide or carbides of vanadium, titanium or zirconium and hence is readily machinable and also stronger and tougher than it would be it contained a large percentage of such carbide or carbides.

I use the terms ferrous metal and ferrous melt with the same meanings in which they are now generally used in industry that is to say to apply to materials selected from the group consisting of iron and steel. By iron of course is included Words. The steels of course include electric furnace steels, open hearth steels, bessemer steels and stainless steel. Steels generally contain some contain such free carbon as graphite; Many elements have been added to iron to make the various steel alloys and it is impossible for me even to give a list of all the known steel alloys. Metals usually added to iron to make steel alloys include chromium, cobalt, manganese, molybdenum, nickel, silicon, tungsten and vanadium.

While in many cases especially when the carbide particles are added by means of the tray 81 it is sufficient to rotate the mold at an angular velocity sufficient to form a cylindrical inner surface on the melt, in some cases forces up to or above 1009 (where g is the force of gravity and equivalent to 32 feet per second per second acceleration) are preferably used. These are easy to attain as can be readily calculated from the equation v =Gr, where v is pie with a motor speed of 1200 R. P. M. G=41g at a radius of one inch, G=82g at a radius of two inches and G=123g at a radius of three inches. With a motor speed of 3000 R. P. M. G=256g at a radius of one inch and G=512g at a radius of two inches etc. The only limiting factor, therefore, is the strength of the mold and steel mold cylinders 3| of inside diameters up to six inches and more can readily be made which will stand centrifugal force up to and beyond 10009. Es-

pecially when mixing the carbide with the ferrous melt or forming the carbide in situ but even also in those cases where I add the carbide to the rotating mold and deposit it on the inner surface of a ferrous melt I prefer to keep the ferrous metal molten and to maintain the mold rotating at an angular velocity equivalent to at least 109 for at least twenty seconds with the carbide or elements thereof present.

With a force many times that of gravity a slight difference in specific gravity will be sufficient to cause the lighter carbide particles to move quickly to the interior of the rotating melt. Indeed angular velocities much lower than 1200 R. P. M. can be used. Most of the elements for making alloy steels above listed have specific gravities greater than those of the three carbides selected as shown in the following table.

Table H j\ Specific Gravity Elements for Making Alloy Steels at Room emp Water= 1 M Chromium 7. 1 Cobalt 8. 9 Manganese 7. 2 Molybdenunn- 10. 2 Nickel 8. 9 Silicon 2.42 Tungstenl9. 3 Vanadium 5. 87

It will be seen from the above table that any of these elements for making alloy steels can be used in considerable quantity while still main- 1'0 taining the specific gravity of the melt 60 above the specific ravity of the carbide particles. Even with silicon, the lightest element in the table, the

. higher specific gravities.

Articles made in accordance with the invention may be hollow cylinders and at least the interior surface will be cylindrical, but the exterior surface can be conical or stepped or otherwise depart from a true cylindrical surface. At the inner surface of such articles there is a layer at least .002 inch thick consisting of carbide and thereof, the carbide being present in the interior layer to the extent of from 20% to 75% by volume. For reasons heretofore explained, the major portion of the articles will be ferrous metal containing not over 5% by volume of the aforesaid carbide.

After the hollow article is made as above indicated the interior thereof is ground preferably with a diamond grinding wheel or it is honed with a honing tool having diamond abrasive sticks. In this manner a smooth surface is provided on the inside of the article so that it can be used as a cylinder or a liner for an internal combustion engine, a bearing, a pump cylinder, etc.

Accordingly the process involves providing a rotatable mold, mounting the mold for rotation lected from the group consisting of vanadium, titanium, zirconium and complexes thereof, rotating the seconds and of the mold at an angular velocity and for a length of time sufiicient to insure the presence of enough of such bide, titanium matter includes titanium metal, ferrotitanium and titanium carbide and zirconium matter includes zirconium metal, ferrozirconium and zirconium carbide. I use the word complexes instead of mixtures because I want to include compounds as well as mixtures.

In Examples 8, 9, 10, 11, 12 and 13, the iron or steel of the cylinder or of the added ferrous metal or both was melted so that in all of the examples there was ferrous melt in the mold while it was rotating. In all of the examples I actually kept the mold rotating at the specified angular velocity and at the specified temperature for minimum of half a minute, but a lesser period will be satisfactory as indicated.

The apparatus is illustrative and the mold might be maintained horizontal at all times using a short hollow shaft 31 and introducing the melt in the form of a stream through the shaft or otherwise proceeding according to any of the examples or according to any part of the description. In many cases an inductively heated mold may be used.

It will thus be seen that there has been provided by this invention cylinders and liners and aprocess for producing the same in which the various objects hereinbefore set forth together with many thoroughly practical advantages are successfully achieved. As many possible en bodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all Without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A hollow article having an interior cylindrical surface, said hollow article being made of ferrous metal selected from the group consisting of iron and steel and having at the interior surface thereof a layer at least .002 inch thick consisting of carbide and said ferrous metal, said carbide being selected from the group consisting of vanadium carbide, titanium carbide and zirconium carbide and mixtures thereof, said carbide being present in said interior layer to the extent of from 20% to 75% by volume, the major portion of said hollow article containing not more than 5 70 by volume of said carbide.

to claim '1, in

which the carbide is vanadium carbide.

3. A hollow cylinder according to claim 1, in which the carbide is titanium carbide.

4. A hollow cylinder according to claim 1, in

which the carbide is zirconium carbide.

Rcferen ces Cited in the file of this patent UNITED STATES PATENTS Number Number

Claims (1)

1. A HOLLOW ARTICLE HAVING AN INTERIOR CYLINDRICAL SURFACE, SAID HOLLOW ARTICLE BEING MADE OF FERROUS METAL SELECTED FROM THE GROUP CONSISTING OF IRON AND STEEL AND HAVING AT THE INTERIOR SURFACE THEREOF A LAYER AT LEAST .002 INCH THICK CONSISTING OF CARBIDE AND SAID FERROUS METAL, SAID CARBIDE BEING SELECTED FROM THE GROUP CONSISTING

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