US3895968A - Method of making finished steel castings - Google Patents

Method of making finished steel castings Download PDF

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Publication number
US3895968A
US3895968A US431233A US43123374A US3895968A US 3895968 A US3895968 A US 3895968A US 431233 A US431233 A US 431233A US 43123374 A US43123374 A US 43123374A US 3895968 A US3895968 A US 3895968A
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Prior art keywords
casting
dies
gates
forming
shearing
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US431233A
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English (en)
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Paul L Mcculloch
Burton O Heinrich
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Individual
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Individual
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Priority to US431233A priority Critical patent/US3895968A/en
Priority to ZA00746698A priority patent/ZA746698B/xx
Priority to DE19742454979 priority patent/DE2454979A1/de
Priority to IT54189/74A priority patent/IT1023372B/it
Priority to JP49137078A priority patent/JPS50101229A/ja
Priority to SE7416169A priority patent/SE418466B/xx
Priority to BE151868A priority patent/BE823773A/xx
Priority to CH1740974A priority patent/CH596918A5/xx
Priority to FR7443384A priority patent/FR2256792B1/fr
Priority to CA217,310A priority patent/CA1047373A/en
Priority to GB488/75A priority patent/GB1489812A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
    • B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
    • B21J5/002—Hybrid process, e.g. forging following casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D31/00—Cutting-off surplus material, e.g. gates; Cleaning and working on castings

Definitions

  • ABSTRACT A method of finishing a casting which involves formation of a pattern having laterally extending gates, preparing a mold, pouring molten metal therein and per mitting it to cool to form a transitional casting.
  • the transitional casting is reheated to a holding temperature above the critical temperature and then, while the casting is still in the plastic state and near the critical temperature, it is acted upon by a set of dies having cooperating shearing edges located at the lateral surfaces thereof for shearing off the gates and parting line fins and having upper and lower surfaces shaped in ac cordance with selected surfaces of the finished casting for forming these selected surfaces to desired shape.
  • the casting is then cooled to ambient temperaure at a controlled rate.
  • Forming includes the bending, punch ing or piercing and coining to size of the casting while it is near the critical temperature.
  • a method is provided for making a finished casting having an at least par tially enclosed cavity or without draft and hence difficult and expensive to make by ordinary casting or forging techniques.
  • PATENTED JUL 2 2 I975 3.895.968 SHEET 5 Forming a pattern in which gates extend laterally away from the lateral surfaces and lie in the region of the mold parting line 5 Preparing a mold using the pattern 6' Pouring molten steel therein Permitting the casting thus formed to cool to produce a nonhomogeneous dendritic structure Reheating the casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the dendritic as-cast structure is converted into a homogeneous austenitic structure Bringing the dies together to a precisely spaced bottomed condition for shearing off the gates as well as any parting line fins which may have been formed in the casting step flush with the lateral surfaces and for formingly engaging the upwardly and downwardly facing surfaces Permitting the casting to cool to ambient temperature at a controlled rate.
  • an object of the present invention to provide a method of making a steel casting in which the resultant casting is highly accurate in shape and dimension as well as structurally sound and reliable, while avoiding the high labor cost and other disadvantages normally associated with cold finishing.
  • Examples of such castings include those having a dimensioned internal cavity or those lacking in draft so as to require special coring.
  • a piece having a cavity or lack of draft may be produced by forging. it is often necessary to resort to extreme pressure to secure flow of the metal under the forging dies resulting in excessive die wear.
  • FIG. 1 is atop view showing a cluster of four castings utilized in the present invention
  • FIG. 2 is a fragmentary vertical section looking along the line 2-2 in FIG. 1'.
  • FIG. 3 is a fragmentary vertical section looking along the line 3-3 in FIG. I;
  • FIG. 4 is a fragmentary vertical section looking along the line 44 in FIG. 1 and taken through the central sprue;
  • FIG. 5 is a time-temperature plot showing reheating and holding above the critical temperature for the purpose of bringing about homogenization and showing the region of the finishing step;
  • FIG. 6 is a phase diagram for carbon steel corresponding to FIG. 5;
  • FIG. 7 is a vertical section taken through a set of finishing dies utilized in the present invention taken along line 77 in FIG. 8;
  • FIG. 7a is a schematic diagram showing the press arrangement
  • FIG. 8 is a vertical fragmentary section taken along line 88 in FIG. 7;
  • FIG. 9 is a section corresponding to FIG. 8 with the dies closed
  • FIG. 10 is a horizontal fragmentary section taken along line Ill-I0 in FIG. 9'.
  • FIG. I] is a perspective view of a finished workpiece
  • FIG. 12 is a table listing exemplary method steps
  • FIG. I3 is a vertical section corresponding to FIG. 8 with the dies modified for punching
  • FlG. [4 is a section corresponding to FIG. 13 with the dies closed;
  • FIG. 15 is a vertical section corresponding to FIG. 8 with the dies modified for coining to size
  • FIG. 16 is a section corresponding to FIG. 15 with the dies closed;
  • FIGS. l7, l8 and 19 are top, front and side views showing a transitional casting utilized in the present in vention
  • FIG. 20 is a cross sectional diagram showing the transitional casting interposed between a pair of dies and with a sizing mandrel in position;
  • FIG. 21 shows the dies in closed position accompa nied by deformation of the casting to final shape
  • FIGS. 22, 23 and 24 are top, front and side views of the finished casting.
  • FIGS. 1 4 there is shown a composite, or cluster", sand casting 10 which includes four individual castings I1, l2, l3 and 14, cast in the same mold.
  • molten metal is poured through a sprue IS with the metal dividing and flowing through horizontal runners l6, 17 (FIG. 4].
  • risers are utilized as indicated at 21 26, the risers being connected to the castings by gates 21a 26a and 22b, 25b, respectively.
  • gate will be used in this description as meaning both the channel connecting the sprues, run ners or risers to the workpiece through which molten metal flows and the solid metal formation which forms in this channel upon solidification of the molten metal,
  • FIGSv l l 4 of the drawings serve a double purpose. They illustrate a typical casting cluster utilized in prac ticing the present invention but they also illustrate the pattern which is utilized in making the mold in which the casting is produced. Since the finished workpiece, illustrated in FIG. I], is of hollow construction, it is necessary to use a central core in each of the patterns. The core elements are indicated at 27. The flask which is used in making the casting has not been illustrated. nor is there any need to do so since such flask is entirely conventional. It will, however, be understood that the mold, of which the lower portion M has been shown, has a parting line which has been indicated at PL in FIGS. 2, 3 and 4.
  • each of the individual castings ll 14 has lateral surfaces, which lateral surfaces have been indicated by letter subscripts; for example, the casting or workpiece 11 has lateral surfaces Ila I Id.
  • the castings have upwardly and downwardly facing surfaces, these being indicated by corresponding numerals with subscripts e I (see FIGS 2 and 3).
  • the gates are so located as to extend laterally away from the lateral surfaces of each casting, and, moreover, gates are positioned to lie in the region of the mold parting line PL.
  • the pattern is used for making a mold, using ordinary molding techniques. and into which molten steel is poured through a central sprue (see 15 in FIG. 4) in accordance with method steps B and C.
  • the molten metal flows into all portions of the mold cavity including the risers 2i 26.
  • the risers serve the conventional purpose of feeding molten metal, through the respective gates, to the workpiece cavities in order to replenish the metal in such cavities and thus compensate for the contraction of the metal which occurs as the molten metal begins to cool.
  • the molten metal When it is poured the molten metal may, for example, be on the order of 3,000F. As shown in FIG. 5, the metal is allowed to cool, step D, and the temperature drops on the descending curve, as indicated at 30, to a temperature at which point the metal has solidified to form a casting. At any time after the casting has cooled sufficiently to solidify, it is removed from the mold using conventional techniques, for example, by shaking out. Sand particles adhering to the casting may be removed by shot blasting or the like.
  • the cooled casting in the as-cast condition will be found to have a random, non-uniform grain structure characterized by one or more of the following: a dendritic macroscopic structure, a Widmanstatten microscopic structure, and a networlctype, cellular or globular microscopic structure.
  • This nonhomogeneous grain structure is responsible for the poor mechanical properties of the casting (cg, brittleness, internal stresses, poor impact properties, etc.) in the as-cast condition. Accordingly, it has become customary to effect a refinement or homogenization of the grain structure and hence improve the mechanical properties, by heattreating the casting.
  • Heat-treating processes involve a heating cycle during which the casting is heated to a holding temperature above the critical or transformation temperature at which the casting is maintained for a holding period during which refinement of the grain structure is effected by conversion of the characteristic as-cast structures mentioned above into homogeneous austenite. Heating and holding are followed by controlled cooling during which the austenite is transformed into a uniform structure consisting of one or more of several transformation products which are desired from the standpoint of strength, hardness, or machineability, The characteristics of the product formed on cooling are dependent on the cooling rate. Heat-treatment processes are generally classified according to the manner in which and the rate at which a casting is cooled. If the casting is allowed to cool in still air at a moderate rate the process is called normalizing".
  • a slow rate of controlled cooling such as in a furnace or the like is re ferred to as "anncaling, and a rapid cooling by quenching in air, oil, water, or brine is called hardening" or quenching". It should also be understood that two or more of these heat-treating techniques may be performed sequentially and that the present invention includes the use of sequential hcat'trcating.
  • the metallurgy of steel castings has given rise to a highly technical vocabulary for communicating fine distinctions in crystalline structure.
  • the casting consists of carbon steel having a typical carbon content of 0.3% as shown in the phase diagram of FIG. 6.
  • phase diagrams similar to that of FIG. 6 exist for all alloy steels so that the present invention is not limited to carbon steel but includes all steel alloys.
  • the casting is reheated at the desired rate along a reheat line 32 (FIG. 5) traversing the upper critical" temperature TC at point 33, defined as the lower boundary of the austenite region (see FIG. 6), and proceeding to an elevated holding temperature 34 which may. for example. be 100F. above the upper critical temperature.
  • the piece is held at such temperature for a sufficient length of time to convert the nonhomogeneous, as-cast structure to a uniform austenitic structure (austenite) throughout the piece, the holding time depending upon the size of the piece and which may, for example, be one hour per inch of thickness of the heaviest section.
  • the effect of holding the temperature above the upper critical level is to transform the as-cast structure into austenitic form as shown. for example, at point 35, assuming a carbon content of 0.3%.
  • the casting instead of simply allowing the piece to cool slowly in the furnace, cool in still air. or quench in liquid. the casting, while still in a plastic state. and near the holding temperature, is placed between a set of dies having cooperating shearing edges located at the lateral surfaces for shearing off the gates. all of which extend laterally, as well as any parting line fins which may have been formed in the casting step.
  • the casting is, at about the same time, acted upon by die surfaces which are distinct from the dies used for trimming. having the desired shape of the casting and which correspond to selected ones of the upper and lower surfaces of the casting for formingly engaging these surfaces so as to insure that these surfaces are in precise position.
  • two or more castings. where cast in a cluster. are operated upon simultaneously by corresponding sets of shearing and forming dies.
  • press 40 is indicated (press details wot shown) having die assemblies 41, 42 which act respectively upon castings ll, 12 (FIG. 7).
  • FIG. 8 which shows die assembly 41 immediately prior to its initial engagement of casting 11, it can be seen that the die assembly 41 is interposed between a vertically. reciprocating head 43 and a bolster 44. As shown schematically in FIG. 7a, the head 43 is reciprocated by a ram 45 acting through spacers 46.
  • cylinders 47 of the hydraulic or pneumatic type having piston rods 48 extending therefrom and through respective bores 49 in the head.
  • the piston rods are biased to an extended position and each cylinder has a relief valve RV and a check valve A for a reason which will appear below.
  • the assembly is made up of an upper die 51 and a lower die 52.
  • the upper die has a generally rectangular mounting plate 53 bolted to the head 43.
  • Bolted to plate 53 are shearing blades 54, 55, 56, 57 (FIGS. 7 8) having shearing edges 58, 59, 60, M, respectively. which are formed and dimensioned to correspond to lateral surfaces Ila, l lb, I I0. I ld respectively of the casting.
  • the movable body portion 62 having die recess 63, and presenting surfaces which engage corresponding upwardly facing surfaces IIe, l If, 111'. l I] of the workpiece, is slideably mounted between blades 56, 57 so as to permit vertical motion of the body relative to the shearing blades. The extremes of this vertical motion are shown in FIGS. 8 and 9.
  • the lower die For cooperating with the upper die, the lower die includes a body portion which consists of blocks 77, 78 secured to mounting plate 81 which is in turn bolted to bolster 44. These blocks are mounted so as to form a recess 65 for receiving the workpiece as well as to present upwardly facing surfaces for supporting the workpiece at its downwardly facing surfaces 11k. I ll. Vertical surfaces 79, serve as shearing surfaces for cooperating with the shearing edges 60, 61 of the upper die. Also included in the lower die are sidewalls 67, 68 bolted to blocks 77, 78 and having shearing surfaces 71, 72 which cooperate with the shearing edges 58, 59 of the upper die. These sidewalls also support surfaces 11g and H11.
  • castings II, 12 with their associated risers 21, 22 and 23 intact are seated in the respective lower dies 52, 52a, with the die assemblies being in the retracted or open" condition (FIGS. 7 8).
  • castings I3, l4 may be permitted to hang in an outboard condition, cantilevered on the runners 16, I7 (FIG. 4) or, if desired. the runner may be severed by any desired means prior to placing the piece in the press.
  • gates, risers and runners are located so as to aid in handling the casting and in accurately positioning the casting in the die.
  • the castings II, I2 are placed in the dies while still at or near the holding temperature at which point the casting is in a plastic state, has a homogeneous refined grain structure, and is of essentially uniform temperature throughout.
  • the fact that the casting is of essentially uniform temperature is significant in respect to die design because the absence of temperature gradients in the casting means that the casting. although of enlarged size due to expansion of the steel. will have experienced the same percentage expansion at all points. Therefore. the desired dimension between lateral surfaces such as 110 and llb, for example.
  • the desired operating range of finishing temperature is indicated at F in FIG. 5 where it will be noted that the temperature ranges downwardly from the holding temperature TH through the critical temperature TC to a point which may be somewhat below the critical temperature. Although it is preferable to finish the casting while it is at a temperature as close to the holding temperature as possible. in a practical case the lower limit of the finishing temperature may be a temperature which lies within the range of lO to 200 below the critical temperature TC. In any event the casting. or castings. when placed in the press will be in a glowing red plastic state, a state in which the metal may be sheared and bodily formed to desired shape using a relatively light shearing-forming force. a force which is only a fraction of the force which would be required if these finishing steps were carried out with the casting in its cold state.
  • FIGS. 8 and 9 Focusing attention on FIGS. 8 and 9, the engagement of the casting 11 by the die assembly 41 will be explained.
  • the press completes its downward stroke but before the casting is engaged by the upper die. the parts occupy the position shown in FIG. 8.
  • the movable die body 62 of the upper die is held in its lowermost position relative to the shearing blades by extended piston rod 48.
  • the force of this initial engagement may be varied by adjusting the escape of fluid from the cylinder 47 through relief valve RV to offer the desired retarding force to piston rod 48.
  • any parting line fins formed at surfaces llc, l Id are engaged by shearing edges 60, 6
  • the lower surface of head 43 butts against the upper surface of movable die body 62 transmitting a final, peak forming force to the workpiece.
  • the ram is retracted causing the shearing edges to move up and away from the newly sheared edges.
  • the movable die body 62 by reason of the pressure which continues to be applied to it by piston rod 48, insures that the casting remains seated in the lower die 52.
  • the movable die body 62 is retracted and the casting, which is still at or near the holding temperature, is released and may be removed from the lower die by any convenient means. Cooling at the desired rate completes the heat treatment.
  • FIGS. 7 10 While, for the purpose of simple illustration, no provision has been included in FIGS. 7 10 for forming in the way of piercing or coining the casting, it will be understood that such piercing and coining may be brought about by suitable piercing elements on the cooperating dies and suitable coining surfaces included within the inner surfaces 63, 64, 65 of the die sections.
  • the die assembly, modified so as to per form piercing is shown in FIGS. 13, I4 in which modified die assembly 41m is shown having a piercing element for forming a hole in the surface 111' of the casting II.
  • the elements of the die assembly which have not been modified for the piercing operation are identified by the same numbers used in FIGS. 7 10 (see for example 43, 56, 81) whereas the elements which have been modified are identified in FIGS. l2, 13 by the same number used in FIGS. 7 10 with the addition of the letter m.
  • piercing has been used in a generic sense to include both use of (a) a piercing, or drifting tool, which is round-nosed and forces its way through an exiting hole and (b) a punch which is sharp edged and which removes metal in creating or enlarging a hole. The latter has been illustrated.
  • FIG. 13 which shows the die assembly 41m just prior to initial engagement of casting 11, the modifications made in the die assembly in order to accomplish piercing will be explained.
  • the ram 43 has piercing element 90 extending from its lower surface and through bore 91 in movable die body 62m.
  • Block 77m in lower die 52m has a cavity 94 having a bore 92 of a diameter equal to the size of the hole to be punched and a larger bore 93 through which the punched metal can pass through and be removed through opening 95.
  • the casting 11 is first engaged and held firmly in position by movable die body 61m.
  • piston rod 48 retracts allowing downward motion of piercing element 90 relative to movable die body 62m.
  • Piercing element 90 will then engage surface 111' at undersized hole 96 and, as the stroke continues, the piercing element will shear away all metal within the region defined by dotted lines 97 in FIG. 13.
  • FIG. I4 The configuration at the completion of the downward stroke is shown in FIG. I4 in which piercing element 90 extends slightly into bore 92 to insure that the metal removed by the piercing element will fall through to the bottom of cavity 94.
  • Retraction of the dies is identical to the sequence described above except that piercing element 90 is retracted along with shearing blade 56 while movable die body 62m through extending piston rod 48 insures that the casting remains firmly seated in lower die 52m.
  • coining to size is performed on the casting while it is still at or near the holding temperature.
  • the distance between lateral surfaces llc, l ld (FIG. 8) is not critical and that the critical dimension is the thickness of the wings having surfaces Hi, I lj, l lk. l I].
  • the die assembly 41 of FIG. 8 is modified as shown in FIGS. [5, 16 in which modified die assembly 4ln is illustrated.
  • the upper die Sln consists of movable die body 62a, slideably mounted between blocks 56n.
  • Lower die 52n is identical to lower die 52 (FIG. 8) except that blocks 77n. 78n are longer and extend beyond lateral surfaces lie, 1 Id so as to present surface against which stop blocks 100, I01 will abut.
  • stop blocks I00. I01 are shown having a relatively limited area for bottoming against the lower die, it will be understood that in a practical case the stop blocks would be designed with an area somewhat larger than the area of the part to be coined to size. However, it should also be understood that often only selected portions need be coined to size.
  • movable die body 62n could be equipped with a localized disc-shaped coining element extending slightly below its lower surface to form a small land area for surrounding a bolt hole in the casting.
  • the casting freely adopts the shape of the dies without any tendency toward spring-back, so that a highly accurate form and dimension for the casting is established-even though the casting may. at the time of placing the dies. be in a warped or misshapen condition. No subsequent straightcning' is therefore required, a major problem when a casting is cold fin ishcd".
  • the casting I] is shown having planar wings which are formingly engaged by the dies so as to insure that they lie true with respect to a horizontal plane
  • the upper and lower die assemblies could be modified so as to present corresponding curved surfaces to the casting if it is desired to shape or bend selected surfaces of the casting.
  • the wing defined by surfaces llk, lll define a curved surface
  • the mold would be designed so as to form a casting having wings curved to the approximate final desired curvature. It is apparent that the die assembly (FIGS.
  • the operation of the dies incident to heat treatment, and following the holding period is effective to accomplish automatically all of the steps which formerly required hand operations. That is, the risers and gates, or sprues, are cleanly severed from the castings along accurate dimension lines in the single stroke of the press. together with other irregularities such as any fins which may have been formed along the parting line during the molding step.
  • the shearing cut is sufficiently smooth so that the chipping and grinding usually thought necessary to finish the casting may be completely dispensed with.
  • the flaskless procedure involves forming a series of mold cavities in a horizontal column of sand having a high green strength, advancing the column past a metal pouring station where molten metal is poured into each mold in turn, and removing the sand mold after solidification has occurred.
  • the nature of the flaskless procedure requires a vertically orientated parting line plane and gates which lie in the region of this plane.
  • changing reference position by rotating the mold 90 results in a configuration which satisfies method step A. Therefore, the method of the present invention is particularly suitable for practice in conjunction with a flaskless casting operation.
  • the dies may be greatly simplified.
  • the dies must have surfaces corresponding to each and every surface on the finished product.
  • the present dies may leave certain portions of the workpiece unsupported, that is, unengaged, during the forming step, concentrating upon those surfaces which are dimensionally signifi cant.
  • the upper surface 85 of the cylindrical portion of the workpiece I1 is not engaged by the body portion 62 of the upper die assembly (see FIG. 9).
  • the castings are independent of one another and freed of all extraneous metal and are of accurate shape and dimension.
  • the finished castings are discharged, using any desired conventional means. Conveniently, the castings will be allowed to cool in still air, thus completing the normal izing of the metal in the castings. Alternatively. the
  • castings may be annealed by cooling more slowly.
  • the castings taken from the dies may be quenched, with or without subsequent tempering as these terms are defined in the art. In any event, the requirement of the final step H (FIG. 12) is satisfied.
  • finishing is done incident to reheating of the casting for homogenizing, e.g., normalizing purposes.
  • the invention does not make use of the original casting heat.
  • finish that is, trim and form
  • the procedure for finishing a casting has involved the making of a pattern which, but for the addition of gates and risers, substantially con forms to the finished workpiece, with the casting resulting from the pattern then being placed in a set of dies for trimming. coining and the like.
  • the invention is not limited thereto and can be utilized to produce a workpiece which includes an at least partially enclosed cav ity and the making of which would normally require use of a core.
  • the original pattern, with its gates and risers is not made in the shape of the desired finished workpiece. Instead, the pattern is made in the shape of a transitional casting with walls having adequate draft to avoid use of a core.
  • the transitional casting thus formed is then reheated to a plastic state above the upper critical temperature and held there a sufficient length of time for homogenization. Then, while the transitional casting is still in a plastic state and near the holding temperature, the casting is placed in a set of dies for the purpose of shearing off the gates and risers, the set of dies including op posed forming surfaces corresponding to the desired upwardly and downwardly facing surfaces of the finished workpiece.
  • the opposed die surfaces are brought together to act upon the transitional casting so that the walls thereof are deformed inwardly to form an at least partly enclosed cavity. The dies are withdrawn and the casting is permitted to cool at a controlled rate.
  • FIGS. 17 l9 a piece having a partially enclosed cavity is set forth in transitional form in FIGS. 17 l9 and in final form in FIGS. 22 24.
  • the illustrations in FIGS. 17 19 may be taken as illustrative, not only of the transitional casting, but of the pattern which is used .to produce it.
  • the workpiece indicated at in its transitional form is of channel shape having side walls 121, 122, which are provided with adequate draft for casting purposes, and which define between them a channelshaped, open-topped cavity 123.
  • the walls 121, 122 are tapered in the vertical dimension as shown in FIG. 18 and the tip of the piece is spade" shaped as indicated at 124.
  • a gate 125 Secured to the opposite, or thicker, end is a gate 125 having a riser 126.
  • a mold is prepared and the casting is molded in the regular way. Since the cavity 123, although bounded by upstanding walls, is open above the parting line PL, no core is required and the casting may be made in the regular way.
  • the transitional casting is then reheated to a plastic state above the upper critical temperature and held there until homogenization occurs. While the casting is still in a plastic state and near the holding temperature, it is placed in a set of dies which have a shearing edge 128 (FIG.
  • the transitional casting while the transitional casting is in the plastic state, it is placed between forming dies 130 (only partially shown) including a lower die 131 and an upper die 132.
  • the upper die has a forming surface 133 which differs from the shape of the transitional casting but which corresponds to the shape of the desired finished casting.
  • a mandrel 135 having a ledge 136.
  • the projection 133 on the upper die formingly engages the wall 122 of the transitional casting, causing the plastic material of which the wall is composed to be displaced laterally and to flow into the space defined by the upper surface 133 and the lower ledge surface 136.
  • the upper edges of the walls of the transitional casting are defomred mutually inwardly so that the cavity 123, instead of being open-topped becomes partially enclosed. The result is to produce the workpiece illustrated in FIGS. 22 24 which differs from the shape of the pattern which is used to produce it and which is distinguished by a partially enclosed cavity of a type normally requiring use of a core.
  • the present invention may be employed for economical production of a cast workpiece which cannot be cast in the usual way and which would, because of the partial enclosure, require resort to a core.
  • the resulting workpiece is, by reason of its cast nature, and by use of the extremely simple forming dies shown in F168. 20, 21, susceptible of manufacture more cheaply than a forging, and with considerably reduced die expense.
  • the dies After the dies have completed their stroke, the dies are opened, the mandrel is longitudinally withdrawn, and the casting is removed and allowed to cool at a controlled rate.
  • the method of making a finished steel casting having lateral surfaces as well as upwardly and downwardly facing surfaces comprises: forming a pattern in which gates extend laterally away from the lateral surfaces and lie in the region of the mold parting line, and in which the upwardly and downwardly presented surfaces are free of extraneous protuberances in the form of gates or the like, preparing a mold using the pattern, pouring molten steel therein, permitting the casting thus formed to cool to produce a nonhomogeneous ascast grain structure, reheating the casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the as-cast grain structure is converted into a homogeneous austenitic structure, then, while the casting is still in a plastic state and near the holding temper ature, placing the casting in a set of dies having opposed forming surfaces corresponding to selected ones of the upwardly and downwardly facing surfaces of the casting and having cooperating shearing edges located at the lateral surfaces, bringing the dies together for shea
  • the method of making a finished steel casting having lateral surfaces as well as upwardly and downwardly facing surfaces which comprises: forming a pattern in which gates extend laterally away from the lateral surfaces and lie in the region of the mold parting line and in which the upwardly and downwardly presented surfaces are free of extraneous protuberances in the form of gates or the like, preparing a mold using the pattern, pouring molten steel therein, permitting the casting thus formed to cool to produce a nonhomogeneous ascast grain structure, reheating the casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the as-cast grain structure is converted into a homogeneous austenitic structure, then, while the casting is still in a plastic state and near the holding temperature, placing the casting in a set of dies having cooperating shearing edges located at the lateral surfaces, and then bringing the dies together for shearing off the gates as well as any parting line fins which may have been formed in the casting step flush with
  • the method as claimed in claim 5 further comprising: placing the casting, while it is in a plastic state and near the holding temperature, in a set of dies having forming surfaces opposite sections of the casting having a critical thickness dimension, and then bringing the dies together to a precisely spaced bottomed condition to establish the thickness dimension simultaneously with the shearing off of the gates and fins.
  • the method as claimed in claim 5 further comprising: placing the casting, while it is in a plastic state and near the holding temperature, in a set of dies having opposed piercing elements and then bringing the dies together to pierce the casting simultaneously with the shearing off of the gates and fins.
  • the method as claimed in claim 5 further comprising: placing the casting, while it is in a plastic state and near the holding temperature, in a set of dies having opposed coining surfaces arranged opposite selected surfaces of the casting, limiting the travel of one coining surface with respect to the other as the dies come to gether so as to bottom said coining surfaces at a predetermined spacing equal to the desired final separation of the selected surfaces of the casting increased by an incremental amount taking into account the expanded condition of the casting at the holding temperature, whereby upon subsequent contraction of the casting due to cooling the selected surfaces will be accurately spaced with respect to one another.
  • the method of making a finished steel casting having lateral surfaces as well as upwardly and downwardly facing surfaces comprises: forming a pattern in which gates extend laterally away from the lateral surfaces and lie in the region of the mold parting line, and in which the upwardly and downwardly presented surfaces are free of extraneous protuberances in the form of gates or the like, preparing a mold using the patten, pouring molten steel therein, permitting the casting thus formed to cool to produce a nonhomogeneous ascast grain structure, reheating the casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the as-cast grain structure is converted into a homogeneous austenitic structure, then, while the casting is still in a plastic state and near the holding temperature, placing the casting between a set of dies having forming surfaces corresponding to selected ones of the upwardly and downwardly facing surfaces of the workpiece and having cooperating shearing edges located at the lateral surfaces, advancing the forming surfaces into firm engagement with
  • the method of making a finished steel casting having lateral surfaces and upward and downwardly facing surfaces and including an at least partially enclosed cavity having a desired internal dimension comprises: fonning a pattern of open topped channel shape providing draft and in which the gate extends laterally away from the lateral surfaces in the region of the mold parting line, preparing a mold using the pattern, pouring steel therein to form a transitional casting, permitting the casting thus formed to cool to produce a nonhomogeneous as-cast grain structure, reheating the transitional casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the as-cast grain structure is converted to a homogeneous austenitic structure, then while it is still in a plastic state and near the holding temperature shearing the gate and placing the transitional casting in a set of dies having opposed forming surfaces corresponding to the desired upwardly and downwardly facing surfaces of the finished casting, bringing the dies together to a precisely spaced bottomed condition with a mandrel of the desired
  • the method of making a finished steel casting having lateral surfaces and upwardly and downwardly facing surfaces including an at least partially enclosed cavity and the making of which would normally require use of a core which comprises: forming a pattern dif fering substantially from the desired shape of the finished casting and in which the cavity is open sided and bounded by upstanding walls having sufficient draft as to enable a core to be dispensed with and in which a gate extends laterally away from the lateral surfaces in the region of the mold parting line, preparing a mold using the pattern, pouring molten steel therein to form a transitional casting in the shape of the pattern, permitting the casting thus formed to cool to produce a nonhomogeneous as-cast grain structure, reheating the transitional casting to a plastic state above the upper critical temperature and holding it there a sufficient length of time for homogenization so that the ascast grain structure is converted to a homogeneous austenitic structure, then while it is still in a plastic state and near the holding temperature, placing the transitional casting in a

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Forging (AREA)
US431233A 1974-01-07 1974-01-07 Method of making finished steel castings Expired - Lifetime US3895968A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US431233A US3895968A (en) 1974-01-07 1974-01-07 Method of making finished steel castings
ZA00746698A ZA746698B (en) 1974-01-07 1974-10-22 Method of making finished steel casting
DE19742454979 DE2454979A1 (de) 1974-01-07 1974-11-20 Verfahren zur herstellung von keine nachbearbeitung erfordernden stahlgusstuecken
IT54189/74A IT1023372B (it) 1974-01-07 1974-11-22 Procedimento per la realizzazione di getti d acciaic finiti
JP49137078A JPS50101229A (zh) 1974-01-07 1974-12-02
SE7416169A SE418466B (sv) 1974-01-07 1974-12-20 Sett att framstella ett stalgjutstycke
BE151868A BE823773A (fr) 1974-01-07 1974-12-23 Methode pour produire des pieces d'acier coule finies
CH1740974A CH596918A5 (zh) 1974-01-07 1974-12-31
FR7443384A FR2256792B1 (zh) 1974-01-07 1974-12-31
CA217,310A CA1047373A (en) 1974-01-07 1975-01-03 Method of making finished steel castings
GB488/75A GB1489812A (en) 1974-01-07 1975-01-06 Method of making finished steel castings

Applications Claiming Priority (1)

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US431233A US3895968A (en) 1974-01-07 1974-01-07 Method of making finished steel castings

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JP (1) JPS50101229A (zh)
BE (1) BE823773A (zh)
CA (1) CA1047373A (zh)
CH (1) CH596918A5 (zh)
DE (1) DE2454979A1 (zh)
FR (1) FR2256792B1 (zh)
GB (1) GB1489812A (zh)
IT (1) IT1023372B (zh)
SE (1) SE418466B (zh)
ZA (1) ZA746698B (zh)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977911A (en) * 1974-05-29 1976-08-31 Mitsubishi Jukogyo Kabushiki Kaisha Method for casting metallic material while toughening the cast piece
DE2829729A1 (de) * 1977-07-07 1979-01-18 Citroen Sa Maschine zum abbrechen der haelse der verlorenen koepfe bei gusstuecken
US20020166357A1 (en) * 1999-12-29 2002-11-14 Saint Jean Industries Method for making light alloy components
US20040035546A1 (en) * 1998-05-04 2004-02-26 Diserio Emile-Thomas Process for manufacturing aluminum alloys and aluminium castings
CN113510231A (zh) * 2021-04-23 2021-10-19 深圳领威科技有限公司 定模组件及压铸机

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3373281D1 (en) * 1983-03-14 1987-10-08 Serio Thomas Di Method of producing pieces of aluminium or aluminium alloy
DE19638506A1 (de) * 1996-09-20 1998-03-26 Leybold Vakuum Gmbh Verfahren zur Untersuchung einer Mehrzahl ähnlicher Prüflinge auf Lecks sowie für die Durchführung dieses Verfahrens geeigneter Lecksucher
FR2778125B1 (fr) * 1998-05-04 2000-07-07 Serio Emile Di Procede pour fabriquer des pieces en alliages coules, et notamment en aluminium
DE102009035702A1 (de) * 2009-07-30 2011-02-03 Benteler Automobiltechnik Gmbh Fahrwerksbauteil für ein Kraftfahrzeug und Verfahren zur Herstellung
DE102009054315A1 (de) * 2009-11-24 2011-05-26 Benteler Automobiltechnik Gmbh Verfahren zur Herstellung eines Kraftfahrzeugbauteils
DE102014221994B4 (de) * 2014-10-29 2023-03-30 Bayerische Motoren Werke Aktiengesellschaft Herstellen und Bearbeiten von Gussteilen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2352408A (en) * 1941-07-03 1944-06-27 Meehanite Metal Corp Method of producing ferrous castings having desired physical properties
US2875109A (en) * 1954-08-25 1959-02-24 Eimco Corp Method for the isothermal treatment of alloys after casting
US2901384A (en) * 1952-02-20 1959-08-25 Renault Method for treating cast iron castings

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2352408A (en) * 1941-07-03 1944-06-27 Meehanite Metal Corp Method of producing ferrous castings having desired physical properties
US2901384A (en) * 1952-02-20 1959-08-25 Renault Method for treating cast iron castings
US2875109A (en) * 1954-08-25 1959-02-24 Eimco Corp Method for the isothermal treatment of alloys after casting

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977911A (en) * 1974-05-29 1976-08-31 Mitsubishi Jukogyo Kabushiki Kaisha Method for casting metallic material while toughening the cast piece
DE2829729A1 (de) * 1977-07-07 1979-01-18 Citroen Sa Maschine zum abbrechen der haelse der verlorenen koepfe bei gusstuecken
US20040035546A1 (en) * 1998-05-04 2004-02-26 Diserio Emile-Thomas Process for manufacturing aluminum alloys and aluminium castings
US20020166357A1 (en) * 1999-12-29 2002-11-14 Saint Jean Industries Method for making light alloy components
CN113510231A (zh) * 2021-04-23 2021-10-19 深圳领威科技有限公司 定模组件及压铸机

Also Published As

Publication number Publication date
FR2256792B1 (zh) 1978-09-29
SE7416169L (zh) 1975-07-08
ZA746698B (en) 1975-11-26
CH596918A5 (zh) 1978-03-31
GB1489812A (en) 1977-10-26
IT1023372B (it) 1978-05-10
DE2454979A1 (de) 1975-07-17
BE823773A (fr) 1975-04-16
FR2256792A1 (zh) 1975-08-01
CA1047373A (en) 1979-01-30
JPS50101229A (zh) 1975-08-11
SE418466B (sv) 1981-06-09

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