US1397603A - Method and apparatus for heating long blanks to forging temperature - Google Patents

Description

W. B. PEIRCE. METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGING TEMPERATURE.

APPLICATION FILED MAR. 81 I9I9.

Patented Nov. 22, 1921.

4 TTOHNE I 3 SHEETS-SHEET I.

W. a PEiRCE. 4 METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGTNG TEMPERATURE.

APPLICATION FILED MAR, 28, I9l9.

139?, wag Patented Nov, 22, MZL

A TTOR/VEY W. B. PEIHCE.

APPLICATION FILED MARx 28, I919.

Patented Nov. 22 1921.

3 SHEETSSHEET 3. L

METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGING TEMPERATURE.

UNITEDTSTATES PATENT OFFICE.

WILLIAM B. PEIRCE, OF NORTH TONAWANDA, ll'FlWv YORK.

METHOD AND APPARATUS FOR HEATING LONG BLANKS '10 FORGING TEMPERATURE.

Patented Nov. 22 1921,

Application filed March 28, 1919. Serial No. 285,860.

ments in Methods and Apparatus for Heating Long Blanks to Forging Temperature, of which the following is a specification.

My present invention relates to the heat ing of metal blanks, preferably to forging temperatures, the commercial and industrial purposes being in some respects quite similar to those set forth in my prior Patents Nos. 1,243,442, 1,243,443 and 1,243,444. The material may be used in similarly long lengths, as for instance, long rods in commercial bundle coils as they come from the rod mills, and these lon lengths of material may be heated to simi arly high tempera tures, as for instance, for use in automatic bolt heading machines or nut punching and forming machines, in a relatively small furnace. But the method and the apparatus herein set forth are radically different from those of my prior patents and they possess certain peculiar advantages.

For instance, the auxiliary apparatus and machinery structurally associated with the furnace is reduced to a minimum, is much cheaper and simpler to operate, and is less liable to get'out of order. p

Moreover, while my present method may be practised with rods of medium or small diameter such as can be easily handled by methods of my prior patents, my present method has special advantages when used for heating thicker material, as for instance, rods halfan inch to an inch in diameter.

' My present method also has the advantage that material of half-round, square or other non-circular cross-section may be employed as easily as round rods, since the steps of the method are such that if desired, the coiling of the material for compactness during heating and the uncoiling for use can very easily be accomplished without any longitudinal twisting or untwisting of the material. That is, if the material starts as an untwisted square bar, it can be delivered as an untwisted square bar; or, if the original material has a twist, it can be delivered with the ori 'nal twist unchanged. This is of particu ar advantage where flat bars sultable for nut blanks are to be heated and temperatures suitablev supplied at forging temperatures to nut punching and the forming machines.

One of the most important features of myv method is the forming of the material into open cylindrical coils and exposing the coils to the heat of the reverbatory furnace by rolling the coils on the floor or other suitable SHPPOI't WIthiH the furnace. The open formation of the coil permits direct penetration of radiant heat to all parts of the ma-.

terial as'well as free circulation of the flammg or hot gases into heating contact therewith. The rolling of the bare coil has the effect of successively presenting all parts of the material at difierent elevations in the furnace, one for each revolution of the coil. Hence, whatever difference of heat there may be between the topmost level of the coil and the floor on which it rolls, that difference is equalized and there is every op ortunity for soaking or internal conduction of the heat uniformly throughout the cross-section of the metal, thereby minimizing the danger of local overheating.

The success of this part of my method depends upon the fact that certain materials, particularly the iron and mild steel rods commonly used for' these purposes, when heated to a satisfactory forging softness, say 1700 to 2000 Fahrenheit, still have enou h transverse or structural stiffness so that the material will maintain its shape as an unflattened, undistorted helical coil with unimpaired rolling ability, provided the diameter of the coil be properly proportioned to the cross-section of the material. The length of the coil is not so important and it need be only long enough for stability while rolling. The most desirable ratio of coil diameter to material diameter will depend somewhat on the quality of the metal and the temperatures to which it is to be heated, but for ordinary rods heated to good forging temperature, I have found that good results may in diameter for inch rods; about 6 to 7 inches for inch rods; say 7 to 71} inches for 4 inch rods; say 7% to 8 inches for 2 inch rod and say 9 to 10 inches for 1 inch rod. These are merely suggestive dimensions for the average commercial round rods.

Any of the above rod diameters will permit a coil diameter smaller than that named, since other things being equal, decreasing the diameter of the coil makes the turns stiflfer against collapse or flattening; 'It is be had with coils 4 to 4% inches preferable to select the largest safe diameter, however, since large diameter coils requlre less power for bending as well as less bending stress on the material in the coil forming machine; the large coils roll more easily over obstructions in the furnacebed and are less likely to stick one against the other as they roll; and the larger the diameter of the coil the greater length of material can be put in a single coil, with .a given clearance between adjacent turns.

It is to be noted that the determination of a safe coil diameter for a given rod diameter, will depend on regulating, the heat of the furnace and regulating the rate of progress of the coils through the furnace and that the larger diameters Will be safer when these are regulated in such manner that the material will be gradually and uniformly heated to, but not much beyond, the desired temperature. Too high furnace heat may result in too quickly heating the surface of the material to welding temperature so that adjacent coils will stick. and too slow progress through the furnace may result in overheating and collapse of the coil.

By my method, however, in which the turns of the coils are well separated and in which all portions of the coil successively roll into and out of the upper regions-of greater heat, the heating is well diffused and uniform throughout the whole cross-section of the metal. it is therefore comparatively easy for one skilled in such matters to keep the heat within the rather wide, practically usable, limits of intensity and distribution.

My complete preferred method of which the above described coil heating is an important feature involves taking desired lengths of the material, rounds, bars or flats,

- whether straight, bundle-coiled, or otherwise; forming the material into cylindrical helical coils having the adjacent turns slightly separated; utilizing the cylindrical shape of the coils for rolling them progressively, preferably in continuous succes sion from the entrance to the exit end of a suitable furnace; regulating the rate of their progress with reference to the heat, so that they will arrive at the exit end at the proper temperature for forging; then unwinding the coil; preferably reeling it oil at right angles to the axis of the coil, and withdrawing the material endwise through a suitable exit opening in the furnace; preferably rotating the coil once for every turn that is unwound, so that no twist is applied to the material. The progressive rolling of the coils in the furnace may be accomplished simply and very. effectively by making the floor of the furnace inclined and permitting the coils to roll down toward the exit by gravity.

The essentials of the apparatus necessary for practice of my invention will be readily,

understood from the above description of the method, the principal essential being a coil forming machine adapted to wind heavy coils to predetermined desired diameters; a furnace of height dependent upon the diameter, of the coils and of length sufficient to contain the desired number of coils, an inclined floor for the coils to roll on, a stop to hold back the train of coils while the last fully heated coil is being unwound and preferably also an endwise insertible and removable mandrel or reel for free rotatable support of the latter coil during the unwinding. The mandrel axis and the stop are preferably water cooled. The coil former may be constructed along the lines of machines now commonly employed for coiling heavy helical springs.

The apparatus as well as the method may be more fully understood from the following detailed description in connection with the accompanying drawings, in which-- Figure 1 is a vertical crosssection of the furnace approximately on the line 1--1, Fig.

2, the coil of heated material being shown in elevation and the support therefor partly in elevation and partly in section;

Fig. 2 is a side elevation of the furnace with the inclined floor and succession of rolling coils indicated in dotted lines;

I Fig. 3 is a top plan view of the same parts including the dotted line showing of the interior; and g Fig. 4 is a detailed view of feed rolls for drawing the material endwise from the furnace and feed it to any desired metal cutting, punching, shaping or forging machine.

The furnace may be of the usual construction and materials comprising masonry preferably refractory, floor 1, walls 2, 3, roof 4, preferably supported, stayed and bound together by a channel frame comprising uprights 6 and horizontal members 7 held by tie-bolts 8. Means for supplying the heating medium, preferably flaming gases from a regenerative furnace are arranged preferably at the rear of the furnace as conventionally indicated at 9, 9.

The floorof the furnace is inclined downward from rear to front as indicated at 10 but preferably'has a horizontal portion 11 at the upper end adjacent a side door 12 through which the coils may be inserted endwise into the furnace. The coils 13, 13 are supplied in continuous succession and roll by gravity down the'inclined floor 10 by progressive steps toward the lower end of the incline. The train of rolling coils is held back and the lowermost coil successively per- These stops are preferably in the form of inverted U-shaped pipes, the legs of which slide in vertical passages through the bottom of the furnace and the upper horizontal portions of which withdraw into short horizontal recesses in the bed of the furnace, when in the the lowermost position. These pipes are water cooled in any desired way, as for instance, by mounting them on crosspipes 18, 19 supplied in any suitable way as for instance through pipe -20 pivoted at 21. Water supplied to the pivot pipe 21 flows through 20 supplying pipe 18 and through flexible connection 22, supplying pipe 19. In the arrangement indicated in the drawings, the water flows in both directions from the center of the pipes 18, 19 and escapes from the end thereof, but any other desired arrangement may be employed. The stops 14, 15 may be operated from either side of the furnace through rod 23 connected. by arm 24 with cross shaft 25 provided at the far side of the furnace with operating lever 26. I

By this arrangement the lowermost coil uniformly and highly heated during its progress down the incline 10 is permitted to escape and roll a slight distance free from proceeding coils. In the lowermost position it is in approximate alinement with the mandrel or unreeling support 27. The latter comprises a hollow shaft 28, a smaller pipe within the same and adapted to be water cooled by water flowing outward through said hollow shaft and returning through said inner tube.

" Mounted on the shaft 28 are the cylindrical drum or reel elements, preferably comprising castings formed with hubs 29, webs 30 and longitudinal enlargements 31.

-. These members are preferably made in sections so that if onebecomes warped or burned or worn before the others, it may be easily and cheaply renewed. The unreeling mandrel is supported on a trolley 32 traveling on track 33 and preferably operated power means diagrammatically indicated as a pressure cylinder 34. When the unreeling mandrel is in position within the furnace, the free end of the shaft 28 is supported by bearing 35. The end of the mandrel where the material is unreeled is preferably supplied with a face plate 36 adapted to rotate closely adjacent, and so close the opening 37 in the wall of the furnace. The opposite opening 38 is provided with a removable closure 39.

In operation, the coils of proper diameter suited to the thickness of the material. are charged endwise into the furnace at intervals which are preferably equal to the time it takes to unreel and use up the coil at the lower end of the furnace. This maintains a continuous train of coils capable of rolling against each other and toward the lower end of the furnace by gravity. When the lowermost coil is sufiiciently heated, its redecessor having been used up, the man rel is withdrawnv endwise by operating cylinder 34, the escapement stops are operated and the lowermost coil allowed to roll into alinement with the mandrel; The mandrel is then inserted to about the position shown in Fig. 1. The free end of the coil is then engaged with the feeding out rolls of the desired metal working machine, usually by rolls of the type indicated in Fig. 4, the man- .drel is then slightly advanced until the flange member 36 substantially closes the opening 37. The feed rolls are then operated to unwind and straighten the coil without twisting it until the material of that coil its side, and rolling the bare coil progressively upon its own periphery-along a suitable support ina reverberatory furnace.

2. The method of heating lengths of material which method consists in rolling bare coils thereof upon a stationary surface within a heated furnace, and feeding the heated material endwise of the material and laterally with respect to the axis of the coil.

3. The method of heating material in lengths, which method consists in forming the same in an open helical coil by winding or bending the material without twisting it, rolling the coil through a furnace to heat the material and finally unrolling and simultaneously rotating the coil to remove the ma terial without twisting it.

4. The method .of heating long metal blanks which method consists in forming the same into open helical coils, each long enough to make a self supporting roller when laid on its side, and rolling the coils upon their own peripheries progressively through a reverberatory furnace.

5. The method of heating material in lengths which method consists in forming the same in open helical coils by winding or bending the material without twisting it, rolling the coils in continuous succession through a furnace to heat the material and successively unrolling and simultaneously is used up. Thereupon the mandrel is again cal coils, and rolling the coils progressively through a reverberatory furnace, said coils being of diameter less than ten times the thickness of the material.

7. The method of heating long metal blanks to forging temperatures, which method consists in forming the same into open helical coils and rolling the coils progressively through a reverberatory furnace, said coils being of such small diameter with reference to the diameter of the metal of the blank that it will substantially maintain its curvature and shape while so rolling at such forging temperatures.

8. A furnace for heating coiled rods, said furnace having a surface on which said coils may be rolled during heating, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be withdrawn endwise to permit moving of a coil into alinement therewith and for advancing the mandrel endwise within said coil to rotatably support the same.

9. A furnace for heating coiled rods, said furnace having a surface on which said coils may be rolled during heating, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be withdrawn endwise to permit moving of a coil, and means for unreeling the material of the coil to straighten the same without imparting .any longitudinal twist thereto.

, 10. A furnace for heating coiled rods, said furnace having a rollway along which a plurality of said coils may be rolled with their axes parallel with each other during heating, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be withdrawn endwise to permit sidewise rolling of the successive coils into alinement therewith and for advancing the mandrel endwise within a fully heated coil to rotatably support the same.

11. A furnace for heatingcoiled rods, said furnace having a rollway along which a plurality of said coils may be rolled with their axes parallel with each other during 7 heating and means for freeing the lowermost coil from contact with the adjacent coil, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be withdrawn eer/nos endwise to permit sidewise rolling of successive coils into alinement therewith and for advancing the mandrel endwise within said coil to rotatably support the same during unwinding.

12. A furnace for heating coiled rods, said furnace having a rollway along which a plurality of said coils may be rolled with their axes parallel with each other during heating, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be withdrawnendwise to permit sidewise rolling of successive coils into alinement therewith and for advancing the mandrel endwise within said coil to rotatably support the same, and means for unreeling the material of the coil to straighten the same without imparting any longitudinal twist thereto.

13. A furnace for heating coiled rods, said furnace having an inclined floor of a width across the incline greater than the length of said coils and a length down the incline equal to the combined diameters of a multiplicity of said coils, a side door in the furnace adjacent the upper end of said incline through which said coils may be inserted endwise one at a time in position for rolling down said incline, means for stopping said coils above the lower end of said incline and for freeing the lowermost coil from engagement with the preceding coil and an opening through which the material ofthe latter coil may be withdrawn endwise by progressive unwinding of the coil.

14. A furnace for heating coiled rods, said furnace having an inclined rollway down which a plurality of said coils may roll by gravity in a continuous trainwith their axes parallel with each other, and means for freeing the lowermost coil from the coil behind it, in combination with a rotary mandrel arranged to project into the furnace, means whereby the mandrel may be Withdrawn endwise to permit sidewise rolling of said lowermost coil into alinement therewith and for advancing the mandrel endwise within said coil to rotatably sup- WILLIAM B. PEIRGE.

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