BE548113A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 



   The present invention relates to an improved process and apparatus for making steel objects of specific shape from bar or wire metal on cold forging machines, such as those known as knockers or upsetting machines. heads, and more particularly the methods and apparatus for cold forging of steel parts, such as screws, bolts, rivets, pins and the like, these apparatus and methods ensuring the moderate heating of the material before the refilling operation -

 <Desc / Clms Page number 2>

 lement or head hatch.



     In the practice of shaping cold forged screws or other parts provided with a head, one encounters great difficulty in forging screws from special wicker steels with medium and high carbon content, in particularly due to breakage or breakage of the metal during the head upsetting operation.



   When using steels of the type in question which are difficult to cold forge, a standard practice in the industry consists in upsetting the heads of the screws in several passes with at least one annealing between these passes, that is to say that the blank is also partially cold forged! This is done on one machine and then annealed, after which cold forging is completed in a second machine often providing four or more shocks. It is obvious that these multiple operations are expensive and time consuming, requiring considerable manpower and tooling and even the proportion of scrap can be high, especially with steels which are more difficult to work then the range of steels that can be cold forged successfully is very limited.

   Such a process requires the use of two head upsetting machines for each job, as well as several dies and the tooling for annealing, then it takes a considerable manpower not only to transport the parts of the machine. first machine to the annealing installation and, from there, to the second machine, but also to assemble the two machines for upsetting the heads for this particular work. In addition, this process generally requires a minimum of four dies and the corresponding punches, which is prohibitively expensive for small orders of special screws.



   We tried to overcome these difficulties by using

 <Desc / Clms Page number 3>

 relatively slow and expensive head upsetting machines using the so-called "progressive" process, in which the screw head is forced back in five or six successive stages to prevent breakage or breakage of the metal.

   Although progressive head upsetting machines are an improvement over the old two-phase drilling process with intermediate annealing, the fact remains that it # has the expense to create and fit several dies and often the corresponding punches, that the usable metals are very limited, that the flow rate is not very high and that the precision and the quality of the production leave much to be desired, the faults and rejects being frequent.



     In accordance. According to the present invention, head-fitted parts, such as screws, can be completely cold-forged from special steels and medium and high carbon steels and other cold-forged ferrous alloys. a single machine '- upsetting the heads -, two strokes by heating the material just before forging by means of a heating device, preferably of the high frequency type, which is placed in close connection with the head upsetting machine , but is thermally insulated therefrom and is controlled to impart a moderate degree of heat to the material.

   The present invention also provides a high production process and apparatus for cold forging. parts fitted with a head from special steels and steels / medium and high carbon content on a single machine which has an essentially safe operation and which greatly increases the range of steels that can be cold forged, then produces screws or other head-mounted parts of improved structure and appearance.



   Other characteristics moreover emerge from the detailed description which follows.

 <Desc / Clms Page number 4>

 
 EMI4.1
 



  3r3.). TÎB :: 4.L0¯. ; '1 ":'; ,, 11 (, \ ;, pure (; Ol1; j, rwat, i..r, .ief-.G" 1ques of operation, of construction, o;, e combination there. :>? 15;., <= Iitr, function and arrangement of parts, which are described below with the help of construction and working examples.
 EMI4.2
 



  Embodiments are shown ;: scl; <5 ..: ati.que- ment, by way of non-limiting examples, in the accompanying drawings.



   Figure 1 is a partial schematic plan of a head upsetting machine, in which the heater specially adapted for carrying out the method of the present invention has been mounted.



   Figure 2 is a partial side elevation, on a larger scale, of part of the head upsetting machine and heater.



   Figure 3 is a longitudinal section, on a larger scale, of the heater and part of the frame of the head upsetting machine.



   Figure 4 is a cross section taken on line 4-4 of Figure 3.



   Figure 5 is a diagram showing the approximate temperatures to which the bar or steel wire is heated prior to the cold forging operations of the present invention for relatively long parts, temples along the bar or of the wire being shown in the graph at the bottom of this figure, in which the solid line curve A is for special steels and 1, in phantom S for mild steels.



   Figure 6 is a side elevation of a tron @@@
 EMI4.3
 of steel given as an example and cut to length from a bar or wire material for the forging operations by the method and apparatus of the present invention.

 <Desc / Clms Page number 5>

 



   Fig. 7 is a side elevation of the same section at the end of the first cold forcing operation @ in accordance with the present invention, a cut away part of the die and the punch, with the aid of which the Intermediate blank is forged, being shown in section and part of the partially forged blank also being shown in section.



   FIG. 8 is a similar view of the same blank in the die with the punch scond and at the end of the second and last phase of cold forging.



   Figure 9 is a side elevation of a different section which is intended to be formed into a forged blank having the same shank diameter as the section.



   Figure 10 is a view of the same section at the end of the first forging operation according to the process of the present invention with a part cut away from the die and the punch, with the aid of which the section is cold forged , a portion of the head of the partially shaped blank being torn off and shown in section.



   FIG. 11 is a view of the same blank at the end of the second and final cold forging phase according to the present invention, the enveloping die and punch being shown in section.



   Figures 12 to 17 are end elevations of the sections and blanks shown in Figures 6 to 11, respectively.



   A preferred conventional form given by way of example of the apparatus according to the present invention, by means of which the method is preferably carried out, is shown schematically in Figures 1 to 4. In the detailed description which follows, The apparatus is described in detail and has certain operating characteristics, then the method of the present invention is next described with reference to this apparatus,

 <Desc / Clms Page number 6>

 
 EMI6.1
 although the method may .àvi <1 <; :; no Stre executed C "'N.; = - i --s: 3
 EMI6.2
 many other very different forms of device.
 EMI6.3
 



  Figure 1 shows, a little scïj'cr.tir., The .acrr.t, ..i: i ;; 3. classic lodiriec pushing machine; a <our, s ¯ du. type; shown in U.S. Patent No.;.; s: eï.7; v, el '.-, ::; 1 on October 3, 1938, which has a bûti 10 affecting the for-M one rand block or piece of cast iron, a pair of rollers 6fev2-
 EMI6.4
 this 12, 14 mounted on the support 16 to advance a wire
 EMI6.5
 18 shown in phantom through a corridor .80 d; ol1S the frame 10 from a suitable feed (no! 'S: r'i, 2:;: 1.t'; e}.



  The steel wire 18 advances intermittently s. through the corridor 20 of the hêti 10 towards the whole lanie and 9cenise of tr2llSport represented sché.l8.ti <;. ue.:: slow in 22 in which sections
 EMI6.6
 or individual work pieces are severed at the end
 EMI6.7
 before the yarn and transported laterally to a suitably shaped figure (not shown) in biti 10.



  After the trsnspcrt sections cut by the: Gilw .-. ¯: cutting and transport 23, the section undergoes s; 1ivantes operations under the action of the delivery punch 84 and è.u? 0LlçOn forging 26 which are both not mounted on the frame or slide 28 of the head upsetting machine. Los :: l0cl: Í :: cs upsetting heads of this type are well known and operate continuously at high speed to shape unts3 -.t "iced into a blank or section. 1 ± t * nt F jnnµ <. , ¯1e; the heads of construction to. * The machine j¯ ± -efouie * the heads are not part of the present invention, they are .. sunri ::. S for simplicity and abr: ..: r the description.

   The. - .. 1: .1C11in. ::; :, the C ¯'001; '1' the Gtes can be ± the one Any of:; ioàl = 1, -, zs i? ol-.3 C.:..l:C: the C. t. "* U4? lJlr forcing and r.: 1'ouler the t4t, js of pieces 2û'¯Iiçu.a, te! 1ev eue (; 1:; 8 screws of c..rr.3, 1: r '"lc, = \.' 4r1 :: .. ¯" '\ .. t1' \.!: '<-,. ,,> vis.ij t8'G6súlv'ol (es, screw? 1 heads if: , panes, r # v ets, bolts, wood screws and r.lo.u8s nieces.

 <Desc / Clms Page number 7>

 
 EMI7.1
 



  A riù <3 a i i î ;; > <i, du ch: tut'j ';' ;; H, which <3HL L .t. <; j¯: 1 4 ;; J: iù =. <5 J;. i '= <; v = 1 (, - in uO d: .us Ha .t.'S77: ULC: (lom16u' 1 bitre tl'ff: C :: 31 <3, <-t arranged between 1-s xnlr ;;. u cl.Tevt: ru: e 13, 14. Fa le tut3. 10, then is n; ontµ o ftiçon can be r4j: 1 <é loti, îtudi Il -., l, f. (.; r It between these parts. The inéc1nS. ame 1 .: clxaui'.L '; y, e 30 co: avn:;. a block 32 preferably in one (, material good conductor of heat, such as copper, brass or aluminum., hollowed out of a
 EMI7.2
 lose; nen.t 54 to receive a coil 36 ,, preferably formed of copper tubes.

   Coil 36 is held in housing 34 by a non-metallic insulator 38 which may take the form of a rectangular pad attached to block 32 and a similar pad 40 attached to a removable plate 42 which is held in assembled position on the coil. block 32 by bolts 44.



   Conduits 46, 48 of coil 36 extend along the outer sides of a pair of conductors 52, 54 and y
 EMI7.3
 are fixed, then are connected at their remote end, to a source, not shown, of cooling liquid, such as water. The coolant supplied by the tubes 46, 48 is also distributed to the channels indicated generally at 54 in the block 32, by means of distribution tubes 56, 58 forming a bypass from the tubes 46, 48, respectively in
60 and 62.



   Bus bars 50, 52 are mounted to and connected to a high frequency current source generally shown at 64, such as a transformer. The high frequency current source can be any suitable conventional transformer or generator. It is preferred to use a variable rate high frequency distribution capable of providing an alternating current of the order of 400 kilocycles and an output power capacity. 10 to 50 kilowatts or more
The wire being fed 18 is guided in the spool
 EMI7.4
 S6 by 1'é.lésa:; e 67 of block 33.

   A second alosase 73 percjà

 <Desc / Clms Page number 8>

 at the opposite end of block 33, supports the wire after it has passed through spool 36, which ensures that the wire is properly supported and guided by the center of spool 35 without coming into contact with it. by ensuring a uniform and often localized heating action. After its passage through the bore 73, the wire 18 enters the furnace 72 which is disposed in the passage 20.

   Furnace 72 is an elongated tube of low conductive trawl material, such as polished stainless steel, and is spaced apart with peripheral ribs 76 to minimize contact with frame 10 and hence heat transmission from wire 18 to frame 10.



   The longitudinal position of the heater assembly 30 is adjusted relative to the frame 10 so that the distance from the blade 22 to the spool 36 is a multiple of the length of the cut section, which ensures that the localized portion of the current wire The heater is, at any one time, a uniform part of the entire section after cutting by the Blade 22. The length of the heater can also be varied for roughing. different, by removing the coil 36 and replacing it with another with its associated parts, so that a more or less long part of the section can be heated. It is evident that the wire 18 is fed intermittently by the advancing rollers 12, 14 depending on the speed at which the sections are cut and transported by the blade mechanism 22.



   In the operation of the apparatus of the present invention, the head thrower is preferably operated at the maximum speed for which it has been designed.



    Although the wire feed is intermittent, the heater coil 36 can be continuously fed even though it is

 <Desc / Clms Page number 9>

 
 EMI9.1
 either to advise to provide means to cut I.1Uto, '] / :: tj (' 1 (; - é: 18nt the feeding of the reel: 3G each hay that the a: ct.ire; stops. In accordance with the invention, 10. the power of the high-frequency source 9. G4 is regulated in t '-; mnt counts <1 <s d.ime;; 1- * nc and the speed of advance of the wire, of so that the fed wire is heated uniformly or locally, when it passes through
 EMI9.2
 to coil ë6, at a relatively moderate temperature, co :: ±: 1 '. this is described in detail below.

   The effect of the high frequency electric heating ensures that the die can be heated in a sufficiently fast manner even at high wire feed speeds and with large wire sizes, then the heating is carried out. substantially uniformly over the entire cross section of the wire.



   Although the temperature ranges are important from a ferrous metal working point of view, these temperatures are not sufficient to adversely affect the coating of the wire normally intended to improve the advance of the wire. The exact composition of these coatings can vary widely and these coatings are often of
 EMI9.3
 organic in nature, then frequently include a heat sensitive material, such as aluminum stearate or the like or a material which may be molybdenum sulfide suspended in oil.

   The temperature of the trunk. One in the navy to push back the heads never approaches a limit 'critical for the steel of which the wire is composed,
 EMI9.4
 of SOr1i8 that there are not <= 'large structural modifications teeth steel. i. '1 when shaped from special steel or a. high content of caroone which work difl'icllement, the pieces obtained 111Uni8S of heads are peoples, i;.; is a great extent, of cases: -; es or ruptures, then -the quality and appearance of the screws, bolts, rivets, tweezers and ano.lor parts ..: llt: 'S obtained are generally;': TZrJÉ: r7.GU.; These are considered (} O., UI1Q possible so far.

 <Desc / Clms Page number 10>

 



   Another advantage of the apparatus of the present invention is that heat transfer to the head upsetting machine and to the feed and feed rollers is essentially avoided. While there tends to be some backward transmission of heat through wire 18, this transmission is compensated by the rapid advance of the wire forward to produce a uniformly heated wire, or, if the heating is localized, the heated parts can be worked or forged before the heat has equalized over the entire length of the fed material.

   The transmission of heat to the frame 10 and thence to the dies is essentially prevented by the isolated position of the heater 30 and the small contact surface between the frame and the fed material.



   As a result of the process of the present invention, it is possible to shape parts with heads, such as screws, bolts, rivets, pins and the like, cut into steels from bar material of special and / or high-grade steels. medium and high carbon, which heretofore could not be completely cold-forged in double-shot head press machines. By "special steels" is meant steels to which one has added. characteristic amounts of alloying elements, such as nickel steels, chromium steels, molybdenum steels, stainless steels and the like.



   By "steels with a medium and high carbon content" is meant steels having a carbon content of at least 0.3%, as well as steels having a carbon content of the order of 0.6% and approaching from the class of tool steels. It is also possible to cold forge large dimension wires so that a wide range of screw blank dimensions, even up to a multiple of 2.5 cm in diameter, can be available in the parts provided with a shaped head.

 <Desc / Clms Page number 11>

 special steels and steels with medium and high carbon content.

   The supply of low-cost parts made from special steels and medium and high carbon steels opens up an entirely new field of use for cold forgings in installations where conventional cold forgings of low tensile strengths were not suitable and in which those with the best strength were too expensive.



   The method of the present invention not only allows a larger range of steels to be used, but its power capacity is generally at least 50% greater than that of prior devices, then the precision and quality are. higher. At the same time, costs are reduced all the more as the complete cold forging operation can generally be obtained by using a single die instead of several dies and the assembly and disassembly time is less. For example, by practicing the present invention, the price of the die may amount to only about 87,500 francs at present prices, while the cost of materials for similar work on a progressive machine would be in the neighborhood of 350,000. frank.

   This is a particularly important factor in the manufacture of small orders of special parts, where the price of the dies previously greatly exceeded the total of the other components of the cost price.



   The process of the present invention depends on the fairly precise control of the temperature of the blanks, as these are cold forged and the process invariably requires that the blank be initially heated before working it and it further requires that the work be done. performs .. 'at a speed such that, taking into account the quantity of metal to be forced in a given time and the rates of heat transmission from the metal workpiece, the workpiece does not protrude into its working part has an average temperature of 343 C and, preferably, does not

 <Desc / Clms Page number 12>

 
 EMI12.1
 not exceeding 315 0.

   The punch temperature of nv ::: trir ;; ¯e d;: r. the operations comprising the formation of cold forged cells are also important and the best results have been found, especially with regard to the duration of the punch, When the punch is operated at around 315 C,
 EMI12.2
 that is to say from 260 to 34oO, the heat of the punch et0Ut comes from the part which it carries out.



   The precise temperatures at which the material or
 EMI12.3
 the blanks are heated and to which it -.ci =: J So: ar = iies by the cutting mechanism to the upsetting or '' orer parts, to the cold of the head upsetting machine, QéDen08nt due to several factors
 EMI12.4
 other / different, such as the type of worked steel, li 3sr0 to which the steel is to be worked or i: 0? '", 8. cold in one or two or more phases, how quickly the steel is cold forged and, to a lesser extent, the shape of the
 EMI12.5
 head or the shaped part to be produced on the blank.



  The specific examples given below are representations of specific applications of the process of the invention, but, in their main aspect, the processes of the present invention are carried out completely, in operations.
 EMI12.6
 #ions of forsspge a. cold or refoa. '! : xenC: zes heads, direction de- -.J --u -. v ........., .-.;, E ± ± S 'Qpass a temperature of 43 C co..e te.Temperature rore :::: the of 1 part of the workpiece or "" "11'1 of a vte t, of., .., ± ''; rence, in the ':; ..: 1le ranging from 260 to 7'6cC Co'e a - e: - L x Ûk, .final of the head of the piece.

   In some cases, the û ¯ xw-u; e may not exceed 232 C although the duration of the punch is much better when the temperature reached by the head
 EMI12.7
 found in yc - .; e from 260 to 313 C.



  To achieve this temperature, the consolation of heat in the uatrice is itself against and is varied according to the extent of the cold forGease to which the

 <Desc / Clms Page number 13>

 metal must be subjected, the speed with which the job is done, the number of head presses used and the heat loss in the machine during the head dozer operation.



   The reason why the duration of the punch is increased is not yet explained satisfactorily, but the great increase in the duration of the punch is easily observed in the operations currently carried out and leading to such a final temperature of the head of the punch. 323 to 343 c and, preferably,
260 to 315 C
By operating at these final temperatures, the head upsetting machines can produce objects with heads of larger dimensions than those obtainable otherwise on a given machine, then the parts thus produced are of more precise dimensions and head upsetting machines work more regularly than not.



   To reach these final temperatures with the usual dimensions of the parts and when it is necessary to work the metal in a normal extent on the head of the blank, the head or the whole blank is then heated to an initial temperature, by example by high frequency heating, at least 62 C and more generally at least 93 C, the working of the metal in the head upsetting operations raising the temperature in the range of 232 to 343 C or, preferably , from 260 to 318 C
When it is necessary to do the head upsetting or cold forging operation in one pass, the initial temperature of the material is between 118 and 204 C and the metal working raises the temperature in the range of 232 to 324 C and, preferably,

   from 260 to 315 C
When the head upsetting or shaping operation comprises a two-pass operation comprising a first cone shaping operation (Figure 7) and a final punching and die-forging operation (Figure 8),

 <Desc / Clms Page number 14>

 The workpiece is first heated to about 65 or 98 C sufficiently so that at the end of the cone shaping operation the average temperature of the head falls within the range of 121 to 339 C and preferably , from 162 to 204 C, this cone shaping operation being immediately followed by the forging operation and producing an average, final temperature of the head of 232 to
343 C and preferably 260 to 315 C.



   When more than two cold forming operations are involved and the part of the workpiece with a head is to be shaped in three or more phases, the workpiece is first heated to a temperature of at least 65 C and preferably 93 C, then in the final working phase generally comprising a punching operation, the forging to grazed, is carried out at a temperature above 222 C or, in a less desirable manner, at 204 C and the temperature reached by the head at the end of labor does not exceed 315 C or, less desirably, 343 C.



   In the final phase of a two or more phase cold forging operation, in which the final head shape is determined, operation to produce a final temperature of 232 to 343 C or 260 to 31500 exhibits the The added benefit of working with less elastic reaction in the head upsetting machine, this factor likely contributing to longer tool life and quieter operation in this temperature range.



   In accordance with the preferred way of carrying out the process of the present invention for cold forcing steel sections or blanks having a certain ductility at relatively cold temperatures, the sections or blanks can be forged without being heated to temperatures. initials above 5:

  58 C (unlike processes which require the blank or section of metal to be heated to temperatures

 <Desc / Clms Page number 15>

 approaching the wheel or to processes which require the metal blank to be stabilized, annealed or subjected to other heat treatment during or immediately after the cold forging operation to correct it for the structure formed by the working of the blank. metal during the cold forging operation).



   The blank or the section of wire or steel bar material has a diameter approaching the general diameter of the finished article to be manufactured; which may be up to 2.5mm or less or alternatively it may have a diameter of 25mm. or more, depending on the capability of the head upsetting machine, in which the cut-off piece or blank is to be shaped by strong pressure among a series of operations.



   Although the method and apparatus of the present invention are generally applicable to a wide variety of steels which are sufficiently ductile to be cold forged in one or more phases, the method and apparatus are applied in the following manner. most effective in two or three phase cold forging of ferrous metals, especially special steels, including stainless steels and tool steels, which cannot otherwise be cold forged in a ptat @ cue manner any.



   In carrying out the process of the present invention, steel sections or blanks having the desired diameter are heated and cut from the supplied material and intermittently advanced from the feed station to the upsetting machine. heads. The heating is preferably carried out in an extremely short period of time and only a short time before the cutting and upsetting operations of the heads, so that in almost all cases the material is heated for at least one second and always. less than two or three seconds, the times exceeding one second being borness @ ires only when it is a question of a relatively heavy material, tulle

 <Desc / Clms Page number 16>

 than a bar material more than 19 mm in diameter.

   The heating can be done in the vicinity of the cutting station and, when the wire or bar material is not heated to a uniform temperature, the heater can be adjusted so that the cutting point on the wire material or bar is relatively cool relative to the hottest part of the material, which provides a cleaner or cleaner cut than would occur if the metallic material was hotter at the point of cut.



   Thus, in accordance with the present invention, the steel material is heated at one location and is intermittently advanced to a cutting station and from there to a head discharge station, the head discharge station. head being placed near the heating station. In this way, the wire or bar material can be heated at will and locally at a moderate temperature; it can be cut while the cut points are still relatively cold and be brought to the head delivery station while the head is still locally heated to a higher temperature than the rest of the feed material.

   Preferably, there are no more than a few lengths of material between the cutting station and the head delivery station, ... so that when the apparatus operates at a total speed of 60 to 250 units or more At, the minute depending on the dimensions of the blanks produced, no more than a few probes and sometimes less than a second elapse between the heating operation and the initial operation of upsetting the heads or cold drilling.

   In this way, sections or blanks can be heated so that some parts of the blank are made more plastic than in the normal cold forging operation, while relatively sections or blanks long ones can keep some parts noticeably Turkish

 <Desc / Clms Page number 17>

 ambient, so that no compressive force of the steel is lost before the cold forging operation, which makes it possible to push the section or blank into a reduction die and to be shaped there at the same time and at the same station as that in which the section or blank is subjected to the head upsetting operation.

   Relatively short sections and those which should not be substantially reduced in diameter, as well as those in which the head should not be abnormally large, can be heated with substantial uniformity and this is preferably done by heating a unit length. of wire or bar material when it advances intermittently, the heating being .sensibly uniform over the entire length of the section and of the blank to be cut in the material.



   Figure 5 shows the conventional non-uniform temperatures which may be used on a length of fed material to be cut into relatively long sections or blanks prior to cold forging operations. As shown; optimum temperatures along the length of the section or blank are: given for a bar or wire which may need to be cut to form a blank or a 19 mm by 190 mm section, one end of which must be reduced in diameter over a substantial part of its length and the other end of which must be shaped into a precisely defined head, the area of the head being equal to about twice the area of the material, from which it was formed, as shown in Figures 6 to 8.



   As can be seen in Figure 5, the length of the bar 18, which advances intermittently, is heated locally by means of the high frequency coil 36 and this is relatively short compared to the length of the bar between the bars. '90 points where she should. be cut by the cutting mechanism 22.

 <Desc / Clms Page number 18>

 
 EMI18.1
 



  In the lower part of FIG. 5, we have; pr4> Jr = nté the classic temperatures of the material which advances intermittently after having been ahaunfée locally. These te-.p raturr-, s vary widely depending on the type of steel or other metal fed and used in the process, but typical values are
 EMI18.2
 data for relatively mild steel, such as S.i1.Z. 13; 0, as well as for a more refractory special steel, such as SAβ. 6150.
 EMI18.3
 



  When the steel leaves the heating position, it has been locally heated to a temperature which approaches 1.1 to 20400 for special steel or about 6 to -20400 for mild steel. However, most of the material has not been heated except by conduction along the material, and at the time of cutting or at most one to three seconds later the hottest part of the bar may vary from 62 to 201 ° C while the cut-off position is notably cooler and the intermediate portions of the bar are substantially at their initial ambient temperature.

   When the bar or wire material is cut by the cutting device, the ends are slightly heated by the action of the cut and the parts of the bar adjacent to the cut ends become more plastic, which facilitates the operations.
 EMI18.4
 of forging which follow iil = 6 immediately.



   Therefore, when relatively long parts are to be forged and especially when one end must be appreciably reduced in diameter over an essential part of its length, the cut section or the blank is heated at its ends leaving the intermediate part of the section or of the substantially unheated blank.

   The end of the section or blank,
 EMI18.5
 which must be reduced in diameter, is heated only 15L "slowly by the heat applied to the heating station and to which
 EMI18.6
 In addition, there is the small amount of heating generated by the action of cutting the material, while the other end of the unit section or of the blank is 6t ', 1-szuf' e at a distance of 16 " '::

  0-

 <Desc / Clms Page number 19>

 
 EMI19.1
 -Keep away from the outside, so that this end is heated to a sufficient extent to allow it to be
 EMI19.2
 shaped by two or more rapid drilled strokes which forge the steel to its desired final shape without raising the temperature above 343 C and, preferably, not above 31510.



   Using the steel section or the blank at the temperatures shown in Figure 5 to shape the finished blank through the phases shown in Figures 6 to 8, the blank where the
 EMI19.3
 long section 18 'is a temperature of about 62 or 9000 at 2'0 /: G%. its front end which is to be shaped into - '.' an enlarged head. The other end of the blank is at a temperature of about 51 to 149 C for a short distance, this erasing
 EMI19.4
 rapidly toning at about fi3E C le! on ± - of the part or of the cut material, which gives a 0rCr3 ': l; i é a little plastic i * 121' i3tCÎ'nt close to a cold length of the bar Who nit has felt nothing of its realism lost.: That is to compression.



  The hot end 11 "section or of -Loimie a part which may be deformed when the blank or. The hole is pushed into the 41 &, 'ÜTiîIS of reduction, this action in- .:; e; ': -:' ± '.: l "" 0 aSSGZ of additional value to make enough of the surface of the Bietal in order to allow it to take the wished fv5 fial.



     In accordance with the preferred manner of carrying out the process of the present invention, such as that illustrated for
 EMI19.5
  "at? i5S cold of a relatively ionized cciep screw blank shown 3.

   figure 6 and in which the part provided with a head is larger than that which is possible to obtain using conventional cold forging techniques, the head is shaped by upsetting 4.5 to 5 times the wire diameter, and even larger heads can be made by the method of the present invention.
 EMI19.6
 



  The temperature at which the cut-off blank is

 <Desc / Clms Page number 20>

 heated, depends to a large extent on the re-rolling operation of the head to be formed and on the composition of the steel from which the blank is shaped. With carbon and low-grade steels in part sizes up to 6.35mm or 9.5mm in diameter, the blank only needs to be heated locally at temperatures ranging from 90 to 118 C while larger dimensions may require temperatures up to 173 C. Certain grades of special steels, stainless steels and tool steels may require temperatures up to 173 to 204 C.



   Using a special steel, such as 4037, and to form the screw blank shown in Figure 6, the cut length of steel wire 18 'was locally heated near its end to a temperature of about 149 C, some heat being taken by conduction on the next length of heated blank before cutting, which slightly heats the other end of the blank to a temperature of about 90 C.

   The operating speed and the small time interval between heating, cutting and cold forging operations are so / short that the temperatures along the wire material do not have time to equalize, because it There are only a few phases between the heating point and forging, and the cutting and advance of the blanks usually takes place at a rate of several cycles per second. Therefore, the central part of the blank remains substantially at its initial temperature until cold forging is performed.



   Fig. 7 is a section showing the heated blank after the first forging operation of the blank or section has taken place. In the first phase of the operation, the wet end of the blank 18 ', which is slightly hot and has a temperature of about 90 ° C, is pushed into the generally tubular shaped part of the forging die.

 <Desc / Clms Page number 21>

 90 and is forcefully engaged in the narrower cylindrical portion 92 of the die until the end (the blank engages the stopper and the ejection member 94 flattening the end of the die 92. During this period (3 the operation,

   the hot end of the blank is reduced to a precise dimension - and: the cold forging work heats the end and the reduced part to a temperature not exceeding 343 C and, preferably, at- below 288-315 C, which gives an accurate dimension to the end portion 96 of the blank 18 'in accordance with the size and shape of the portion 92 of the die.

   As the die and the discharge punch 24 continue to move back towards the stopper member 94, the other end of the blank is forced to form the head 98 therein in accordance with the shape of the die 24 and the opening. enlarged of the die 100 and at the same time the head is heated by this working of the steel above its initial temperature of 118 C, but above the temperature of 343 C and, preferably, at - below 288 to 315 C.



   In practice, the dimensions and the shape of the end 98 provided with a head of the blank 18 'can vary widely and the diameter of the head can even be equal to. 2 to 2.5 times the initial diameter of the blank.



     When the upsetting operation illustrated in Fig. 7 is completed, the partially forged blank is then subjected to a second forging operation in the same die and by a second set of die and punch. The blank is still in the cylindrical die 92, it bears on the stopper 94 and it is subjected, while it is hot,

   to the powerful cold forging action of the die and the forging punch 26 which form the desired cavity in the end of the upset head 98 and bring the steel of the upset head 98 into substantially exact conformity with the enlarged portion of the heads 100 of the die 92 by further heating the

 <Desc / Clms Page number 22>

 
 EMI22.1
 head 100, axis without exceeding li te;:?: '' rature: tWX: ll: 1U: L c.ë0 15 <- 'J (;, preferably, without exceeding' 3S6? 1 31i> C. The stop ejection 94 then ejects the finished blank 100
 EMI22.2
 motor and then left to r <; i'roiLil after which it can be-subjected, if allowed, other operations of threading, machining, finishing and heat treatment.



   When the blanks do not have to be dismetered and, above all, when the blanks are relatively short, the blanks cut into the bar die or wire can be heated over their entire length. As shown in Figure 9, the steel blank 110 is heated to a temperature.
 EMI22.3
 ture of at least 90 0 and, preferably, nose protruding y '.;. "';:;

   8, after which the blank is conveyed to the 11 N cold fogease dies, 114 for upsetting the head end; ' el 'ébe1.;. C; -Le by shaping the repressed head 116 .after which the threaded blank is again forged by the punch 120 to finish the operations.
 EMI22.4
 punching cold forging tions, natriqaje and final io-rreaje of the head between dies 112 and 120.

   The forging work in these two phases usually raises the temperature of the steel from 38 to 62 C but is controlled so that the temperature of the blank never exceeds 343 C and either
 EMI22.5
 preferably maintained below 88 sis "3, Other shapes of steel parts with head
 EMI22.6
 cold forging can of course be shaped using appropriate dies and punch forcing and upsetting heads by applying the methods and steps described above.
 EMI22.7
 



  : r .:; 1T'.UTCaTlOiVS 1. Method of drilling,.; ea2; e of profiled steel pieces in bars or wire provided with a head, using the grooves of a head upsetting machine, characterized in that that the steel coated with lubricant is heated to a temperature of at least

 <Desc / Clms Page number 23>

 
66 C, a blank is cut, and the steel blank is forged by axial compression, while maintaining the maximum temperature of the blank, during the successive operations, between 163 and
343 C 3 Process for forging profiled steel parts into bars or wire fitted with a head, using dies from a head upsetting machine,

   characterized in that a steel blank coated with lubricant is heated to a temperature of between 66 and 204 ° C. and the hot steel blank is forged. fairy by axial compression thereof, while maintaining the temperature of said blank below 343 C,
3.

   Process of cold forging of profiled steel parts in wire or bar without a head using a head upsetting die and at least @ @ @ a punch making a single pass, characterized in that advancing successive lengths of said material covered with lubricant, said material is heated, it is cut into sections, the temperature of the sections of heated material being between 66 and 232 C, and the blank is cold forged in at least one pass, the forging speed and heat losses being such that the temperature of the blank does not exceed 343 C.



   4. A method of forging profiled steel parts into bars or wire provided with a head, using at least one die for upsetting the heads in order to form the parts by axial compression of the material, characterized in that the Lubricant coated steel is heated to a temperature between 66 and 204 C, a blank is cut there and the steel blank is quickly forged in a single pass, the speed and extent of forging being such as the temperature maximum of the blank does not exceed 316 C.



   5.Process of cold forging of profiled parts in bar or wire provided with a head, in several passes, characterized in that the steel coated with lubricant is heated

 <Desc / Clms Page number 24>

 
 EMI24.1
 3. a te.li?1ttü2'v C. '?. t1'y:' i. '> ,. t-: iL>:.; .OJ nt 1 = 1- C, oji y <J 'cc: = j: <. =. i'3 ê1.ut: hü on the gold.,; c: Ia2'w l.ltJllt 1; vûµ- = <. ,.: 7Âzl 1> <;>. CvY (i; r '..,. "/ ¯On axial, li velocity of V.'I. Y:.'. WlÂU t.:ll <> 'fl.-, 1 :: .i,: .. N> .lrà1iJ. ","; Maximum of the roughing d ': 9,: - :: - e! 1: iS to'¯6 iJ.



  6. Process o fc'rcae - "i cold profiled steel wire jets with a head, using a:.: I; rice% r == 1'or-
 EMI24.2
 and
 EMI24.3
 1st the heads / at least one poiu'lon J CélractSri S8 in that we heat a steel wire reccuvcrt cze lubri ± 1 * ;: at a Ge, .l ::? 1ro.ture
 EMI24.4
 in
 EMI24.5
 between cd and 204 C, on / dµco.-1pe a blank, this blank is forced, at one of its axiG7.e compression, to form an agranie head and the blank is drilled again
 EMI24.6
 at the same end to force a cavity in the enlarged head
 EMI24.7
 and, simultaneously, for 1 '± ",, mer COI: 1:; ÙÈ: te, 18nt said head, the
 EMI24.8
 forging speed of the heated blank being such that the
 EMI24.9
 temperature of the awning blank does not exceed;: 16 C.
 EMI24.10
 7.

   Cold forging process 9.of profiled parts in
 EMI24.11
 steel wire provided with an E; head, in several passes, characterized
 EMI24.12
 by heating parts of a coated steel blank
 EMI24.13
 lubricant with a te: ipe-, rature between 66 and 316 C, one
 EMI24.14
 -: - he cuts a blank, simultaneously reducing the thickness
 EMI24.15
 of said blank and one partially sharpens a head to its
 EMI24.16
 other end, before the temperature has equalized
 EMI24.17
 throughout the entire slab, by cold fGrJe2ye using a col.p, axial recession of the blank, the speed of the piercing being such that the temperature of the blank does not exceed 34K C.



  8. Method of f'or ,, - e6.:se of profiled steel parts in at least one die and a punch with r¯xfoulel bar or wire provided with a head, using / the heads , cā ractérisé in that we heat a 2bauvlle in ;; cjei, covered with lubricant 3. a temperature ini tiulates between 66 and 2o ,, loC and we twist by compression exi <1.e 1 "} 1Juuclle chau1 ' fairy, speed and inpcrtl:! nce of L'O] 'Leuce 6 being td 1':; 8 r: ue la te. <lpr1ture le l'4bauLbe 1 # e not exceed :: '; 4: j ( ;. v.

   Process followed 1'-, rovendicutiou G, ex, .. ûctlf; t en

 <Desc / Clms Page number 25>

 
 EMI25.1
 that the blank is initially heated to a temperature of at least 95 le i: 'ort; e8e ttY <; J.n place in at least three: pusses, the final pass being carried out while the temperature of the blank is between h52 and ô16 É and 1 -:., s first pr: s,;: es :: r :: 'nt resulting in blank temperatures between 177 and 316 C.



     10, Apparatus for heating and forging a wire material, characterized in that it comprises means for advancing the
 EMI25.2
 material, means of i :: uide.f; e for said material, heating means placed between the advancement and guide means
 EMI25.3
 and having a low thermal conductivity, means intended for cutting the material, and means for subjecting the sections of material to a succession of passes in a die for upsetting the heads.



     11. Apparatus according to claim 10, characterized in that the heating means' comprise a heating coil
 EMI25.4
 High frequency induction wire, through which the wire passes.
 EMI25.5
 



  12. Apparatus according to claim II, characterized in that the high-frequency coil and its support are refrcidis by a circulating liquid.



  1S. apparatus for heating wire material; ix. # == ;. be ? a machine to push back the heads, characterized in that it includes a frame in i'OIDne The block -...; - I- \ o;: 'l "c' -: '",: = "pitàs; eza .ui, i- .; a fi * .E "inside the to a ± l'jiie,, ¯, ¯ ¯ eleotri.-ue coil supported by said isolated ais block; siectiiiu;> ;;;. t ;; ¯.i Js colui here, O7..3ns to circulate a coolant liquid .. in the laughter of the block, and means ùestincs 3. to provide a high frequency current) 4 the coil '.



  '4' "l 1¯ ',".,', ",: .L, i <üiéàrc i'iJ, -î # ,, + īnt 1. Apparatus for heating;" t =: Cl8: i? 8 811 wire to be fed a Y: 1 & clline fi push back the heads, characterized in that it comprises a frame in el.me (10 metal block having a fluid internal passage, an electric coil

 <Desc / Clms Page number 26>

 supported by said block electrically isolated therefrom, a pair of wire guides formed in the frame at opposite ends of the spool and li ne therewith, means for circulating a cooled liquid slow in the passage inside the block and the means for supplying a high frequency current to the coil.



   15. A process for forging profiled steel parts provided with a head, as described above.



   16. Apparatus for heating wire material as described above or in accordance with the accompanying drawings.