EP0054343B1 - Procédé et dispositif pour la fabrication de barres coniques - Google Patents

Procédé et dispositif pour la fabrication de barres coniques Download PDF

Info

Publication number
EP0054343B1
EP0054343B1 EP19810304219 EP81304219A EP0054343B1 EP 0054343 B1 EP0054343 B1 EP 0054343B1 EP 19810304219 EP19810304219 EP 19810304219 EP 81304219 A EP81304219 A EP 81304219A EP 0054343 B1 EP0054343 B1 EP 0054343B1
Authority
EP
European Patent Office
Prior art keywords
metallic material
temperature
heating
blank
accordance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19810304219
Other languages
German (de)
English (en)
Other versions
EP0054343A3 (en
EP0054343A2 (fr
Inventor
Tetsuo Kato
Shozo Abeyama
Makoto Saito
Hiroyasu Nagasaka
Masashi Mizuno
Toshio 1811-5 Aza-Kamiyashiki Endo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daido Steel Co Ltd
Original Assignee
Daido Steel Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP17503180A external-priority patent/JPS5797819A/ja
Priority claimed from JP17627680A external-priority patent/JPS57100816A/ja
Application filed by Daido Steel Co Ltd filed Critical Daido Steel Co Ltd
Priority to AT81304219T priority Critical patent/ATE8970T1/de
Publication of EP0054343A2 publication Critical patent/EP0054343A2/fr
Publication of EP0054343A3 publication Critical patent/EP0054343A3/en
Application granted granted Critical
Publication of EP0054343B1 publication Critical patent/EP0054343B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0075—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rods of limited length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2281/00—Making use of special physico-chemical means
    • C21D2281/02—Making use of special physico-chemical means temperature gradient

Definitions

  • This invention relates to a method for manufacturing tapered rods and an apparatus therefor. More particularly, it relates to the method for manufacturing tapered rods and bars from a predetermined metallic material extremely efficiently, i.e., minimizing the material loss and maximizing the productivity, and also to an apparatus applicable for the method.
  • tapered rods employed for the rapidly prevailing tapered coil springs are provided with a larger diametered portion (a) in the central portion and a continuously diameter diminishing tapered portions (b) on either side of the former, as shown in Fig. 1.
  • a rod having the larger diametered portion (a) in the central portion and the diameter diminishing portions (b) on either side is actually employed as a material in production plants of the tapered coil springs.
  • a coil spring made of a tapered rod of this type the varying trend of its height which is observed according to the variation of load is non-linear (A) as can be seen in Fig.
  • the tapered rods as material of the tapered coil springs have been conventionally manufactured chiefly by machining wires or rods of a desired metallic material. Machining of the metallic material naturally yields a great deal of material loss, and needs in addition much time, remarkably degrading the productivity.
  • the invention concerns a method for manufacturing a tapered rod according to claims 1 and 13 and concerns an apparatus for carrying out the method according to claims 17 and 21.
  • the pre-selected metallic material is imparted locally temperature-gradient in the axial direction by heating and that the heated metallic material with the locally gradient temperature pattern is axially stretched by pulling.
  • the metallic material placed under tensile force for pulling will be a tapered rod having a locally varied diameter in the axial direction according to the gradient pattern of the heating temperature.
  • a metallic material or blank can be made into a desired tapered rod, in this invention, only by being imparted a desired pattern of temperature-gradient heating to the taper needed portions thereof alone before being given the axial tensile force.
  • a desired tapered rod can be obtained in a remarkably short time, eliminating all of the conventional tedious and time-consuming processes such as machining process which needs much time and material loss, hot forging process which requires a long and inefficient forging time, etc.
  • This method can be said to have much contributed to the cost reduction of the tapered rods through the simplification of the process and the shortening of the required time.
  • strain rate i.e., rate of deformation of the sectional area of the metallic material per unit of time when it is stretched or pulled to be deformed in the axial direction is of extreme importance. It is furthermore important that the deformation of the sectional area in the minimum diametered portion is kept within a predetermined extent. They have found that effective manufacturing of the desired tapered rods can be achieved by observing this principle in the actual practice.
  • timewise pattern of pulling has given the following features to the method of this invention.
  • a metallic material is pulled by tensile force, under the influence of axially temperature gradient heating, at a rate of strain or deformation within the range of 0.5 %/sec-1000 %/sec in the minimum diametered portion for forming a tapered rod with an axially varied diameter
  • the speed of pulling must be varied such as gradually from high speed to low, reducing intermittently or stepwise the pulling speed by dividing the whole pulling amount into several sections.
  • This pattern of pulling enabled to form effectively a desired tapered portion without incurring breakage of material by local necking and to simultaneously from a cylindrical and parallel portion with a constant diameter in the minimum diametered portion.
  • Metallic materials used for forming the tapered rods in accordance with this invention are usually in the form of wires and rods. Usually they are of steel, but other non-ferrous metals are by no means excluded.
  • the metallic material is desired to be steel wire rod containing carbon of 0.35-1.10% by weight, and further containing, if desired, silicon not exceeding 2.5%, manganese not exceeding 1.5%, copper not exceeding 3.0%, nickel not exceeding 3.0%, chromium not exceeding 5.0%, molybdenum not exceeding 1.0%, vanadium not exceeding 1.0%, boron not exceeding 0.05%, aluminum not exceeding 0.1 %, and titanium, niobium, zirconium, tantalum, tungsten, hafnium respectively not exceeding 0.5%, and the balance in iron.
  • Carbon content of the above-mentioned steel wire rod as the preferable material for the tapered rods should be regulated within the range of 0.35-1.10%.
  • quench hardness is difficult to be obtained in the heat treatment process after the coil formation, which deteriorates necessary characteristics as a spring.
  • proeutectoid cementite will become enormous, which deteriorates life of the spring due to fatige.
  • silicon is effective for improving load loss resistance
  • manganese is good for improving hardenability
  • copper is effective for enhancing weather proof and preventing decarburization during the heat treatment
  • nickel is effective for improving the hardenability and strength (toughness)
  • chromium and molybdenum improve hardenability and resistance to temper softening
  • vanadium is good for improving strength by fining crystal particles
  • boron is capable of improving hardenability by adding trace amount thereof
  • aluminum is effective in elongating the life against fatigue as well as in fining crystal particles so as to lower the ductile-to-brittle transition temperature
  • titanium, niobium, zirconium, tantalum, tungsten, hafnium are respectively advantageous in forming fine carbides so as to improve the resistance to temper softening.
  • All of those additives may be contained separately or in combination within the predetermined ratio of content.
  • Other inevitably contained elements as trace amount of impurities in the course of industrial manufacturing process of the steel wires as the material such as phosphorus, sulphur, arsenic, tin, antimony, zinc, selenium, etc. are all harmless.
  • the pattern thereof should be varied in many ways according to the materalistic quality and dimension of the steel wire, the heating temperature, the tensile condition, the shape of the taper desired, etc. It may be determined specifically for each case, not be decided uniformly or indiscriminately. What can be said in general is that a portion of the steel wire under a high temperature will become finer or thinner in the later tensile operation and a portion under a low temperature less thin. Consequently, for the formation of a continuous taper where the diameter increases or decreases continuously as shown in Fig. 1 a temperature gradient pattern in (a) or (b) of Fig. 3, for example, is preferably utilized.
  • the maximum heating temperature is preferred to be maintained within the range of 600°C-1000°C.
  • breaking elongation of the material becomes low, for example, in case of the earlier mentioned steel wire the elongation against breakage being less than 40%.
  • the material may be broken before it is finally made into an aimed tapered rod due to a possible local necking.
  • oxidization and decarburization of the material surface rapidly progresses so as to greatly deteriorate the life of the final product as a spring against fatigue, which is an undesirable phenomenon.
  • the temperature gradient heating As to a way of imparting the temperature gradient heating, all of the known methods such as direct heating, high frequency induction heating, gas burning heating, infrared ray heating, indirect heating by an electric furnace, etc. are permissible. Any one of those methods may be chosen in accordance with the circumstances.
  • the following two are, for example, recommended as preferable, (1) heating the metallic material directly so that the predetermined temperature-gradient pattern may be formed thereon in the axial direction, and (2) after having heated or while heating the metallic material up to a predetermined high temperature cooling down the same, thereby adjusting the temperature, so as to form the predetermined gradient pattern thereon in the axial direction.
  • heating amount or cooling amount per each portion of the metallic material in the axial direction can be varied according to the pattern of the desired taper, such as by dividing the whole length of a taper, from the central portion to the end portion on either side thereof, into several sections for giving to each section respectively varied amount of cooling air required according to the pattern of the taper, by positionwise varying the diameter or the pitch of electric coils used in a high frequency induction heater in the axial direction of the metallic material according to the pattern of the taper, or by positionwise varying the flow amount of the fuel gas for varying the extent of heating according to position in the axial direction of the metallic material according to the pattern of the taper, and in case of electric resistance heater input amount of the power to a plural series of resistance heating elements can be preferably adjusted per each position of the metallic material according to the pattern of the taper.
  • a metallic material which is given in this predetermined temperature gradient pattern is applied tensile force in the axial direction while being under the gradient heat so as to become a desired tapered rod by gradually changing its diameter according to the pattern of the temperature gradient.
  • a portion under a high temperature becomes small in the diameter and a portion under a low temperature becomes less small in diameter.
  • This tensile force is applied on a metallic material under the influence of the temperature-gradient heating according to the quality, shape, and the targeted form of the taper so as to get a desired rate or speed of strain on the material.
  • this rate of strain of the material must be controlled by all means, for efficiently producing tapered rods of desired shape, while the material is pulled under the temperature-gradient heating. It was also discovered by the inventors that controlling of the rate of strain is preferably made at the minimum diametered portion (maximum uniformly contracted portion) of the formed tapered rod within the range of a certain predetermined value.
  • the tapered rods made by the method of this invention should be applied tensile force at the minimum diametered portion, i.e., the portion under the highest temperature of heating, within the range of process-strain rate (e) 0.5 %/sec-1000 %/sec.
  • process-strain rate e
  • 0.5%/sec should be regarded the lowest limit, because the temperature-gradient pattern in the axial direction actually functions as if it were flat or non- gradient at a rate less than this limit value 0.5%/sec.
  • the rate or speed of strain (e) is meant the amount of deformation per unit of time at the minimum diametered portion, more specifically, the amount of variation of the sectional area, which can be determined in general by the following formula, wherein
  • a metallic material under a predetermined temperature gradient heating when it is pulled at a constant crosshead speed, possibly produces a contracted (constricted) portion at a relatively early stage of pulling, forming a tapered portion only without parallel portion some time, or forming parallel portion only some other time with a tapered portion, even if it is made, having a relatively small rate of reduction.
  • a good tapered rod with a large rate of reduction can not be got by this pulling way of a constant speed.
  • This invention has succeeded in obtaining an excellent tapered rod with a large rate of reduction, perfectly eliminating the conventional disadvantage, by adopting the above-mentioned specific pattern or mode of pulling.
  • Theoretical reasoning for this simultaneous achieving of the tapered portion with a large rate of reduction and the parallel portion can be made as follows:
  • tapered rods having a pair of opposite tapered portions c, d are made from a continuous long wire or a rod by a continuous and repetitive forming operation
  • a long wire or rod having a plurality of tapered portions with a predetermined equal distance therebetween can be, before or after a necessary after-treatment and/or after-process, cut at a predetermined position one after another to have finished tapered rods of constant length.
  • this method is also effective to form one or two tapered rods from a relatively short material of limited length instead of the earlier mentioned long material.
  • the taper portion formed on the material may be various in its shape, such as linearly and continuously diameter increasing or decreasing like one show in Fig. 3(c), with one or two steps in c (d) portion, or outwardly convex or inwardly concave.
  • various modifications are permissible, for example, forming only one taper portion, forming a large diametered portion in the middle with two small diametered portions on either side thereof just contrary to the mode in Fig. 3(c), in addition to the mode having two large diametered portions on either end as can be seen in Fig. 3(c).
  • the undermentioned apparatus is preferably employed.
  • An apparatus including a pulling mechanism for pulling a metallic material of wire stack chucked at two points on the axial direction of the material in a direction enlarging the distance between the two points, and heating means composed of plural steps arranged between the two points for heating the metallic material at each step so as to form a predetermined temperature gradient pattern to the material, whereby the metallic material is imparted the temperature-gradient heating while being pulled in either direction by the pulling mechanism to become a tapered rod with a varying diameter in the axial direction thereof.
  • An example of the apparatus is shown as a diagrammatic view in Fig. 4, wherein numeral 1 designates a round steel rod.
  • the rod 1, which is chucked at a chuck 2, 2 on either end thereof is pulled by a suitable means such as a hydraulic cylinder (not shown) so that the distance between the two chucks 2, 2 may be enlarged. That is to say, the rod 1, is pulled in two directions marked with D arrows so as to be elongated between the chucks 2, 2.
  • a suitable means such as a hydraulic cylinder (not shown) so that the distance between the two chucks 2, 2 may be enlarged. That is to say, the rod 1, is pulled in two directions marked with D arrows so as to be elongated between the chucks 2, 2.
  • high frequency induction heaters n pieces from H 1 to H n , whose number of coil winding is identical for each, are arranged in the axial direction of the rod 1 such that each of the heaters constitutes a heating zone for each position of the rod 1 in the axial direction thereof.
  • each of the coils H 1 ⁇ H n independently controlled or regulated high-frequency current to a predetermined extent is flowed from a controlling means 3.
  • a controlling means 3 By means of varying the amount of current flowed to each coil H,-Hn' density of the induction current flowed in each position of the rod 1 is varied, which means the heating amount to the rod 1 is varied according to the position thereof. It can be said further in other words that a temperature-gradient pattern is formed corresponding to each position of the rod 1.
  • the invented apparatus is further provided with a series of heat-measuring meters or temperature detectors T l- T n , each being faced to each of the heating zones on the rod 1, for measuring or detecting the actual temperature of the heated zone respectively. In order to adjust the heating temperature at each heating zone, the temperature picked up at the meters T,-T n is respectively fed back to the controlling means 3 for thereby controlling the current amount flowed to each of the coils H,-H n independently.
  • the rod 1 which is given a temperature-gradient heating to each heating zone thereof while being pulled in either D direction at the chuck 2, 2, is affected by respectively different amounts of high-frequency heating according to position in the axial direction.
  • the rod 1 will show different rates of extension or elongation, although it is under one uniform tensile force, according to the position in the axial direction of the rod 1. This is why a desired taper is formed.
  • the current flowing to the stepped coils H i -H n is respectively controlled or regulated, and the actual temperature at each heating zone formed by the coils H I -H n is measured by the meters T I -T N and fed back for thereby controlling the temperature of the coils H i -H n to a target value. Consequently the temperature of each coil H i -H n can be regulated at will for desirably varying the form of the taper. The heating temperature and consequently the form of the taper can be exactly controlled in such an apparatus.
  • the density of the coil turn number should be made larger in the induction heating coils located in the central portion of the metallic material in the axial direction and that of the coils located the farther away from the central portion made smaller, and similarly the diameter of the coil should be, if a way of varying the coil diameter is adopted, made smaller in the induction heating coil located in the central portion of the metallic material in the axial direction and that of the coils located the farther away from the central portion made larger.
  • direct resistance heating method is also preferably applicable. While directly flowing electric current to a wire state metallic material from the two points thereon in the axial direction, dispose a plurality of cooling zones in the axial direction of the material for imparting portionwise controlled cooling to each of the positions on the material. The heated material by the current flowing while being under pulling in either direction is pattern- wise cooled by the temperature gradient cooling zone. The material thus can be formed into a tapered rod with varying diameter in the axial direction.
  • the heating amount by the direct resistance heating is measured at any suitable position between the two points on the material for controlling the heating amount by the data of the measurement.
  • This apparatus is characterized in that the temperature of heating at the measuring position itself is so controlled as to be at the targeted level.
  • Numeral 11 designates a round steel rod, each end thereof is chucked respectively by a chuck 12, 22 for being pulled by a not-shown suitable pulling means such as a hydraulic cylinder in an inter-chuck distance enlarging direction, i.e., in the direction marked with D arrows enlarging the length of the rod.
  • the chucks 12, 22 simultaneously function in this connection as a contact for flowing the current of direct resistance heating.
  • the current led through a current adjuster 15 is fed, having been regulated to a predetermined amount, to the rod 11 by way of the chucks 12, 22 to directly heat the same.
  • C 1 -C n are arranged to constitute cooling zones at each position of the rod 11 to be cooled.
  • cooled gas such as air is supplied from a gas supplying means 14, for example, a compressor, through each passage P 1 ⁇ P n under control of flow amount controllers S 1 ⁇ S n so as to cool each position of the rod 11 faced respectively to the coolers-by-air C 1 -C n .
  • a known temperature detector consisting of a lense 16 capable of detecting the surface temperature of the rod 11 covering the whole length thereof and an image sensor 17 is disposed for measuring the surface temperature of the rod 11 at least at a portion opposite to a cooler C m located in the central portion of the rod 11 between the two chucks 12, 22.
  • the temperature detector collects radiated energy from the surface of the rod 11 to generate a signal corresponding to the temperature.
  • the signal from the temperature detector (16, 17) which is corresponding to the surface temperature of the rod 11, is applied to a temperature converter 19 for being, after having been converted there to an electric signal, led to the current adjuster 15 and a cooling control system 18.
  • the current to be flowed to the rod 11 is so regulated based on the received temperature signal as to be adapted to the set value therein, i.e., the targeted heating temperature at the measurement position.
  • a commanding signal is generated, caused by an electric signal from the temperature convertor 19, to motors M 1 ⁇ M n according to the set controlling pattern therein.
  • Flow amount adjustors S 1 ⁇ S n are respectively actuated by each motor M 1 ⁇ M n to adjust the air amount V 1 ⁇ V n led to each of the coolers-by-air C 1 -C n .
  • the rod 11 is cooled in this mode to a predetermined temperature at a desired axial position, that is to say, the rod 11 receives a predetermined pattern of heating under a predetermined pattern of temperature-gradient.
  • the temperature of the central portion m of the rod 11 is adjusted by the regulation of the current amount flowed there. This adjustment of heating is carried out by regulating with PID action the current amount flowed to the rod 11, through the current adjuster 15 aiming the target temperature value Tm, based on the input value from the temperature converter 19 which is under the influence of the detected data of the surface temperature of the rod 11 at the middle portion by means of the temperature detector (16, 17).
  • the whole heating condition of the rod 11 can be detected or known.
  • heat adjustment or regulation conducted at the middle portion of the rod 11 is preferably adopted. It is of course possible to detect the surface temperature at a place of the rod 11 other than the middle portion for presuming therefrom the whole heating condition of the rod 11 and conduct the heat adjustment suited for the detected condition. If and when the temperature pattern given to the rod 11 is altered the detection places of the surface temperature are naturally altered, and it is also possible to detect the surface temperature at plural places of the rod 11 for performing the heating regulation based on the predetermined targeted value.
  • the cooling control i.e., current flow heating plus air cooling
  • the cooling control is normally not practiced. Only when the temperature T m at the position m has largely overshot cooled air is blown through the passage P m into the cooler-by-air C m . In some cases, however, it is rather preferable, according to the pattern of the temperature-gradient, to carry out the heating regulation at the position m by parallelly using the current flow heating and the air cooling, which naturally permits the heating regulation at other places of the rod 11.
  • Temperature at other places than the position m is usually started to be adjusted by cooling when the temperature at the position m has reached the targeted temperature T m , because the position m is the place to be heated highest. It is of course permissible to begin adjusting the temperature of the other places by regulating the heating temperature by air cooling at the beginning of heating, if the circumstances require.
  • the cooling adjustment is executed by controlling the flow amount V 1 ... V n of cooling gas (air) delivered to the coolers-by-air C, ... Cn which is conducted by the motors M,, M 2 , ... M n through suitable adjustment of the degree of opening of the valve or slit in the flow amount adjusters S 1 ,... S n .
  • the flow amount or supply amount of the cooling gas can be determined beforehand, according to each temperature gradient pattern by experiments or the like.
  • the temperature of the rod 11 can be thus regulated in two ways, one being the heating regulation to the current flowing thereto by regulating the current amount through adapting the actually measured surface temperature of the rod 11 to the target temperature, and the other being the cooling control executed by the plurality of coolers-by-air C1,... C n axially arranged which are variable in the cooling capacity from each other due to the predetermined amount of cooling gas flown to each of them.
  • Such parallel regulation of heating and cooling enables effective formation of a temperature-gradient pattern shown in Fig. 3(a), for example.
  • a material, or a rod 11, placed under such a temperature gradient is, when bidirectional predetermined tensile force is applied between the two chucks 12, 22, formed into a tapered rod with taper portions c, d shown in Fig. 3(c) because of positionwise different rate of elongation of the material.
  • the temperature of the rod 11 at the temperature measuring position m which is the reference for the heating regulation, can be exactly controlled to the target value T m , but as to the temperature at other places some discrepancy or difference may take place between the actual heating temperature and the target temperature, because it is controlled in two ways, i.e., cooling from the coolers-by-air C 1 ,..., C n , whose amount of cooling gas is determined by experiments or the like, and direct resistance heating.
  • the flow amount of the cooling gas introduced to the coolers-by-air C 1 ,..., C n is also controlled by the temperature data measured by the temperature detector (16, 17).
  • the temperature detector (16, 17) carries out for this reason the temperature detecting at plural positions in the axial direction of the rod 11, and a commanding signal from the cooling control system 18 is generated after each termination of one taper formation cycle for being received by the coolers-by-air C 1 ,..., C n as data for controlling the flow amount of the cooling gas in the next taper formation cycle.
  • determination of the cooling gas flow amount is executed per each heating and temperature raising of the rod 11 for one taper formation cycle, but the determined value is by no means changed during one heating and temperature raising cycle, which means the control of the cooling gas flow amount is executed only intermittently.
  • Determination of cooling gas flow amount to each of the coolers-by-air C 1 ,..., C n is performed, more specifically, in the undermentioned mode.
  • set value un of the motor M 1 for determining the cooling gas flowing amount for the next controlling cycle of the cooler-by-air C is determined by the calculation of the following equation in the cooling control system 18 wherein designates a set value for the motor M, in the previous cooling cycle, and k and k' are constants in the adjusting operation.
  • the set value for the motor M for determining the flow amount of the cooling gas can be calculated in the above-mentioned method, which enables a further exact cooling control well suited to the target temperature distribution in the next taper formation process or cycle. It is also possible, instead of respectively calculating from the data of actual measurement of the surface temperature at each position of the rod 11, to measure at plural positions thereon the actual temperature for deducting the temperature distribution in general and to determine the cooling amount or blowing air amount each of the coolers-by-air C 1 ,..., C n , based on comparison between the measured temperature distribution and the targe temperature distribution.
  • FIG. 8 A further excellent embodiment of an apparatus for this direct resistance heating method is shown in Fig. 8, wherein dimensional data of the actually produced taper pattern is entered to a calculator, in addition to the conventional control of the taper pattern based only on the surface temperature of the rod 11, for performing more exact cooling control adapted to the target taper pattern. Allotting the same numerals and signs to the same places as in the previous embodiment for omitting the description, only the dissimilar places are explained hereunder.
  • Numeral 13 designates a temperature detector including a lense and an image sensor as in the previous embodiment, and to each of the coolers-by-air C,, ... , C n arranged in the axial direction of the rod 11 predetermined amount of cooling gas which is controlled under a command from the cooling control system will be led in.
  • a tapered portion in an article processed in one taper formation cycle is measured dimensionally of its taper portion by a dimension measuring device 20 for being entered to a temperature pattern adjuster 21, wherein adjustment or correction of the target temperature distribution pattern is carried out. More specifically, comparison between the target temperature pattern set in the temperature pattern adjuster 21 and the measured temperature pattern just entered is conducted for altering the temperature pattern which has been so far the reference for the cooling control. Relation between the dimensionally indicated taper and the temperature distribution pattern is made more close and intimate. Relation between the attempted taper pattern and the temperature pattern are not necessarily accordance in actual experiments, but discrepant sometime, wherein the temperature pattern adjuster 21 has ita raison d'etre.
  • Adjusted temperature pattern information from the temperature pattern adjuster 21 is entered into the cooling adjustment system 18, wherein regulating command for directing the cooling gas flow amount to each of the coolers-by-air C 1 ,..., C n for the next taper pattern formation process is generated based on the entered temperature pattern from the temperature converter 19 according to the corrected temperature pattern.
  • the metallic material made into tapered rods is usually in a wire state, but it may be a rod member, a hollow pipe member.
  • shape of the material rectangular, square, etc. in section are all permissible; as to the species of the material non-ferrous metals are permissible besides the usually employed steel.
  • the tapered rods obtained by a method as claimed have a variety of uses, besides the use as tapered coil springs, such as for antennas, ski stocks if the material is of hollow, lamp posts, etc.
  • Test pieces (round bars) A and B of steel material SAE 9254 at room temperature, whose diameter was 6.35 mm and length 170 mm, were grasped on either end by a water cooling chuck leaving the heatable area approx. 100 mm inbetween. Direct resistance heating was made in both pieces so that the middle portion thereof might be heated up to 850°C ⁇ 5°C. Temperature distribution at that time is shown in Fig. 9. The piece A which was imparted such a temperature distribution was applied tensile force at an average rate of strain 10%/sec under the pulling speed of 50 mm/sec, and the piece B under the same condition of the temperature distribution was applied tensile force at an average rate of strain 100%/sec under the pulling speed of 100 mm/sec. Result of taper formation on both pieces are shown in Fig. 10.
  • both pieces A and B which had been heated to form a temperature gradient were stretched or elongated by the axial pulling action at the validly affected distance from 100 mm up to 130 mm.
  • a taper having the minimum diametered portion substantially in the middle thereof was formed, with a diameter continuously increasing towards either end in both pieces.
  • the diameter in the middle of both pieces A, B were respectively 4.83 mm, wherein rate of reduction was 42.1%, and 4.70 mm wherein rate of reduction 45.2%.
  • test piece (round bar) C of the same steel material was heated so as to be of uniform temperature in the axial direction distribution for being pulled axially at an average rate of strain 100%/sec, at a pulling speed of 100 mm/sec, as shown in Fig. 9. It was turned out, as can be seen in Fig. 10, that the minimum diameter portion did not fall in the middle portion of the piece, the diameter did not continuously diminish, and a local necking took place.
  • the resultant temperature distribution is shown in Fig. 11.
  • the diameter in the central portion was 7.1 mm and the rate of reduction observed there was 44.1%.
  • a test piece E of steel rod of JIS SUP 7 at room temperature having a diameter of 9.50 mm and a length of 900 mm, was chucked by a water cooling chuck and applied high-frequency induction heating, with coil individually different in diameter so as to form a temperature gradient pattern along the heatable area of 500 mm, wherein the temperature in the central portion being 900°C ⁇ 5°C and that on either end portion 650°C.
  • the temperature distribution was in such a state as shown in Fig. 11.
  • an average rate of strain was 60%/sec and speed of pulling 300 mm/sec.
  • the piece E which possessed the inter-chuck distance of 500 mm was elongated to 700 mm, and the formed taper had the minimum diametered portion in the central portion and a continuously diminishing diameter.
  • the diameter of the piece E in the central portion was 6.45 mm and the then rate of reduction was 53.0%.
  • Axial tensile force applied afterwards with an average rate of strain 50%/sec at a pulling speed of 150 mm/sec showed an elongation of the inter-chuck distance of 300 mm up to 390 mm.
  • the minimum diametered portion was located substantially in the middle thereof and the diameter was continuously decreased towards the middle.
  • the diameter in the central portion of the piece F was 4.55 mm and the rate of reduction observed there was 48.9%.
  • the piece was heated by directly current flowing, while simultaneously employing a plurality of air cooling means, individually different in the amount of blowing air, arranged in the axial direction of the test piece, so as to form a mountain "like temperature gradient pattern along the inter-chuck distance of 200 mm, with a peak in the central portion of 850°C.
  • the piece of steel having the above-mentioned temperature gradient pattern was deformed afterwards by pulling while varying the rate of strain i in the central minimum diametered portion.
  • the maximum reduced ratio under uniform deformation at each rate of strain are shown in Table 1 as the resultant data.
  • the maximum reduced ratio under uniform deformation (%) signifies here the amount of deformation until immediately before the occurring of a necking as a premonition to a breakage, that is (A o ⁇ A) ⁇ 100/A o , i.e., (sectional area of the material-sectional area of the minimum diametered portion) ⁇ 100/sectional area of the material.
  • the numerical data in Table 1 is shown in Fig. 15 as a graph.
  • the resultant data of the MR ratio (%) is parallelly shown in Table 3. In any case of steel material an excellent MR ratio was well proved.
  • a piece of steel rod containing C: 0.61 %, Si: 1.94%, and Mn: 0.81%, having a diameter of 6.35 mm, obtained by rolling and drawing was grasped on either end by a water cooling chuck for being heated by the direct resistance heating method, accompanied by a plurality of cooling means individually different in the amount of air blowing and arranged in each position in the axial direction of the piece so as to form a mountain like temperature gradient pattern along the heatable distance between the chucks of 200 mm wherein the peak of the pattern was 850°C.
  • the MR ratio i.e., the rate of reduction could be made large by the gradual decrease of the rate of strain. Deformation by pulling in the range of such a large MR ratio made the formation of an aimed taper quite easy, because it diminishes the labour hour or labour amount. As can be observed in the figure the larger the rate of variation from the initial speed to the final speed becomes, the larger MR ratio is obtained.
  • the obtained MR ratio was only 26% or so.
  • Example 6 On a piece which had been imparted the temperature gradient pattern in Example 6 was applied a two-stepped pulling as shown in Fig. 17(a) and (b).
  • the two-stepped pulling mode is effective in improving the MR ratio, and further the higher the rate of strain in the first stage is, the larger becomes the MR ratio.
  • a test piece of steel rod which had been imparted a predetermined temperature gradient pattern by the mode described in Example 6 was given a three-stepped pulling operation as shown in Fig. 8(a) and (b).
  • Second way was different from the first way only in the rate of strain applied in the third stage, which was changed to 10%/sec.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Metal Extraction Processes (AREA)

Claims (26)

1. Procédé de fabrication d'une barre effilée à partir d'une ébauche (1, 11) en matière métallique, caractérisé en ce qu'on applique une force de traction à l'ébauche (1, 11), dans sa direction axiale (D), pendant que l'ébauche (1, 11), est dans un état chauffé, avec un gradient de température dans la direction axiale (D) de cette ébauche (1, 11), grâce à quoi la barre formée possède une partie effilée (c, d) ayant un diamètre variable en direction axiale qui correspond à un profil du gradient de température.
2. Procédé selon la revendication 1, dans lequel on applique la force de traction à l'ébauche (1, 11) en matière métallique après que cette ébauche a été chauffée de façon à présenter le profil de gradient de température dans sa direction axiale (D).
3. Procédé selon la revendication 1, dans lequel on refroidit de manière réglée (Ci-Cn) l'ébauche (1, 11) en matière métallique chauffée jusqu'à une température prédéterminée, afin d'établir le profil de gradient de température dans sa direction axiale (D), avant l'application de la force de traction.
4. Procédé selon la revendication 1, dans lequel on applique à l'ébauche (1, 11) en matière métallique chauffée avec ledit profil de gradient de température, une force de traction correspondant à une vitesse de déformation prédéterminée.
5. Procédé selon la revendication 1, dans lequel la partie effilée (c, d) possède un diamètre qui varie de façon continue dans la direction axiale (D) de l'ébauche (1, 11) en matière métallique brute.
6. Procédé selon la revendication 1, caractérisé en ce que le profil de gradient de température a une forme en cloche, dans laquelle la température est plus élevée dans la partie proche de l'axe central de l'ébauche (1, 11) en matière métallique et diminue progressivement à des distances croissantes de la partie centrale.
7. Procédé selon la revendication 6, caractérisé en ce que l'ébauche (1, 11) en matière métallique est un fil ou barre continu et en ce que le chauffage pour produire ledit profil de gradient de température est effectué de façon répétée sur le fil de métal continu avec un intervalle prédéterminé, pendant que l'ébauche (1, 11) en matière métallique est soumise à la force de traction.
8. Procédé selon la revendication 1, caractérisé en ce que la température de chauffage maximale, lorsque le chauffage avec ledit profil de gradient de température est appliqué à la matière métallique dans sa direction axiale (D), est comprise dans la plage de 600°C-1000°C.
9. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce que l'opération consistant à chauffer l'ébauche (1, 11) en matière métallique, dans sa direction axiale (D), avec ledit profil de gradient de température, est effectuée avant d'appliquer la force de traction axiale à ladite ébauche, afin de déformer celle-ci dans la direction axiale (D) de façon intermittente et répétée, et en ce que la matière métallique qui a pris une forme effilée est coupée dans la partie de diamètre minimal (E), afin d'obtenir continûment des barres effilées qui sont effilées à chacune de leurs extrémités.
10. Procédé selon la revendication 1, caractérisé en ce que la déformation de traction destinée à l'obtention de la partie effilée (c, d) est appliquée avec une vitesse de déformation dans la plage de 0,5%/s­-1000%/s, mesurée dans une section de diamètre minimal(e).
11. Procédé selon la revendication 10, caractérisé en ce que la force de traction est appliquée à l'ébauche (1, 11) en matière métallique après que celle-ci a été chauffée avec un profil de gradient de température prédéterminée, et en ce que la vitesse de traction de l'ébauche (1, 11) est modifiée progressivement de façon à passer d'une valeur élevée à une valeur faible.
12. Procédé selon la revendication 11, caractérisé en ce que la vitesse de traction de l'ébauche (1, 11) en matière métallique est diminuée par intermittence et par étapes, en divisant la traction en plusieurs étapes.
13. Procédé de fabrication d'une barre effilée à partir d'une ébauche (11) en matière métallique sous forme de fil, caractérisé en ce que l'on chauffe directement cette ébauche (11) par passage d'un courant électrique entre deux points de ladite ébauche (11) et en établissant un profil de gradient de température de chauffage prédéterminé entre les deux points sur l'ébauche (11), par une commande individuelle du refroidisement (V1-Vn) dans chaque zone d'un ensemble de zones de refroidissement disposées entre ces deux points, avant d'appliquer une force de traction entre ces deux points, afin de former une partie effilée (c, d) ayant un diamètre qui varie dans la direction axiale (D) de l'ébauche (11), la température de surface d'une partie quelconque de l'ébauche (11) étant mesurée pour commander la valeur du courant sur la base des données correspondant à cette mesure, afin de pouvoir régler ainsi à une valeur désirée la température de la position de mesure de température.
14. Procédé selon la revendication 13, caractérise en ce que la mesure de la température de surface est effectuée dans une partie centrale entre les deux points sur l'ébauche (11) en matière métallique.
15. Procédé selon la revendication 13, caractérisé en ce que la mesure de la température de surface est effectuée, en plus de la commande du chauffage direct par résistance, à un ensemble de positions situées entre les deux points sur l'ébauche (11) en matière métallique, et en ce que les données de température qui sont ainsi obtenues sont utilisées dans la commande du refroidissement (V1-Vn) dans chacune des zones de refroidissement, au cours d'un processus ultérieur de formation d'une partie effilée.
16. Procédé selon la revendication 15, caractérisé en ce que l'on mesure la dimension réelle d'une partie effilée (c, d) formée par le chauffage et la traction au moyen de la force de traction, pour régler ainsi le profil de gradient de température désiré, et en ce que l'on utilise le profil de gradient de température réglé pour la commande du refroidissement (V1-Vn) dans chacune des zones de refroidissement, au cours d'un processus ultérieur de formation de partie effilée qui est basé sur ces données de température.
17. Dispositif pour mettre en oeuvre le procédé des revendications 13 à 16, pour la fabrication d'une barre effilée à partir d'une ébauche (11) en matière métallique dans un état linéaire, caractérisé en ce qu'il comprend:
un mécanisme de tirage (12, 22) destiné à serrer l'ébauche (11) en deux points de celle-ci et à tirer cette ébauche (11) au moyen d'une force de traction, dans une direction (D) qui augmente la distance entre ces deux points;
un mécanisme d'application de courant électrique (15) destiné à faire circuler un courant de valeur prédéterminée entre ces deux points, afin de chauffer directement l'ébauche (11);
un ensemble de moyens de refroidissement (ci-Cn), disposés entre les deux points de serrage de l'ébauche (11), et dont les capacités de refroidissement (V1-Vn) respectives sont réglables;
des moyens de détection de température (16, 17) capables de mesurer la température de surface de l'ébauche (11) à au moins une position située entre les deux points; et
un mécanisme de commande de la température de chauffage (19) destiné à commander le chauffage par le courant fourni par le mécanisme d'application de courant électrique (15), sur la base d'un signal d'entrée provenant des moyens de détection de température (16, 17).
18. Dispositif selon la revendication 17, caractérisé en ce qu'il comprend en outre un mécanisme de commande de refroidissement (18) destiné à commander individuellement la capacité de refroidissement (V1-Vn) pour chacun des moyens de l'ensemble de moyens de refroidissement (C,-Cn), sur la base d'un signal d'entrée qui provient des moyens de détection de température (16, 17).
19. Dispositif selon la revendication 18, caractérisé en ce qu'il comprend en outre un mécanisme de mesure de dimension (20) destiné à mesurer la dimension réelle d'une partie effilée (c, d) formée par le chauffage et le tirage, et un mécanisme de réglage (21) destiné à régler le profil de gradient de température désiré sur la base des données de dimension qui sont fournies par le mécanisme de mesure de dimension (20), grâce à quoi la commande de la capacité de refroidissement dans chacun des moyens de refroidissement est effectuée, conformément au profil de gradient de température réglé au niveau du mécanisme de réglage (21), sur la base d'un signal d'entrée provenant des moyens de détection de température (13; 16, 17), dans le mécanisme de commande de refroidissement (18).
20. Dispositif selon l'une quelconque des revendications 17 à 19, dans lequel le mécanisme de tirage (12, 22) fait fonction d'élément de tirage au cours du serrage et du tirage de l'ébauche (11) en matière métallique, ainsi que de contact pour faire circuler un courant électrique dans l'ébauche (11), afin de chauffer directement celle-ci (11).
21. Dispositif pour mettre en oeuvre le procédé des revendications 1 à 9, pour fabriquer une barre effilée à partir d'une ébauche en matière métallique dans un état linéaire, caractérisé en ce qu'il comprend:
un mécanisme de tirage (2) destiné à serrer l'ébauche (1) à deux points de celle-ci, et à tirer cette ébauche (1) au moyen d'une force de traction, dans une direction (D) qui augmente la distance entre ces deux points; et
un ensemble de moyens de chauffage (H1―Hn) destinés à chauffer individuellement l'ébauche en matière métallique (1), avec un profil de gradient de température qui est déterminé par ces moyens, l'ébauche en matière métallique à laquelle l'ensemble de moyens de chauffage (Hi-Hn) a appliqué un profil de gradient de température prédéterminé, étant tirée par le mécanisme de tirage (2) de façon à prendre la forme d'une barre effilée ayant une partie effilée (c, d) avec un diamètre variant en direction axiale.
22. Dispositif selon la revendication 21, caractérisé en ce qu'il comprend un mécanisme de commande (3) en plus de moyens de détection de température (T1―Tn) destinés à mesurer la température de l'ébauche (1) en matière métallique qui est chauffée par l'ensemble de moyens de chauffage (H1―Hn), dans le but de commander de façon réglable la température de chauffage dans chaque zone de chauffage, sur la base de la température réelle de la matière métallique (1) qui est mesurée par les moyens de détection de température (T1―Tn).
23. Dispositif selon la revendication 21, caractérisé en ce que l'ensemble de moyens de chauffage (H1―Hn) est formé par des moyens de chauffage à induction à haute fréquence.
24. Dispositif selon la revendication 23, caractérisé en ce que les moyens de chauffage à induction à haute fréquence (H1-Hn) sont constitués par un ensemble de bobines, ayant des nombres de spires respectifs variables, disposées dans la direction axiale de l'ébauche en matière métallique (1) et connectées en série pour faire circuler dans ces bobines des courants ayant des valeurs prédéterminées.
25. Dispositif selon la revendication 23, caractérisé en ce que les moyens de chauffage à induction à haute fréquence (Hl-Hn) sont constitués par un ensemble de bobines ayant des diamètres différents qui sont disposées dans la direction axiale de l'ébauche (1) en matière métallique et sont connectées en série pour faire circuler dans ces bobines des courants ayant des valeurs prédéterminées.
26. Dispositif selon la revendication 23, caractérisé en ce que les moyens de chauffage à induction à haute fréquence (Hl-Hn) sont constitués par un ensemble de bobines, à chacune desquelles un courant électrique est appliqué indépendamment, qui sont disposées dans la direction axiale de l'ébauche en matière métallique (1), et en ce que l'on forme un profil de gradient de température prédéterminé en faisant varier la densité de courant circulant dans chaque partie de la matière métallique, en faisant varier le courant qui est appliqué à chacune des bobines.
EP19810304219 1980-12-11 1981-09-15 Procédé et dispositif pour la fabrication de barres coniques Expired EP0054343B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81304219T ATE8970T1 (de) 1980-12-11 1981-09-15 Verfahren und vorrichtung zur herstellung verjuengter stangen.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP17503180A JPS5797819A (en) 1980-12-11 1980-12-11 Manufacture of tapered rod
JP175031/80 1980-12-11
JP17627680A JPS57100816A (en) 1980-12-13 1980-12-13 Manufacture of tapered rod
JP176276/80 1980-12-13

Publications (3)

Publication Number Publication Date
EP0054343A2 EP0054343A2 (fr) 1982-06-23
EP0054343A3 EP0054343A3 (en) 1982-07-21
EP0054343B1 true EP0054343B1 (fr) 1984-08-15

Family

ID=26496422

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810304219 Expired EP0054343B1 (fr) 1980-12-11 1981-09-15 Procédé et dispositif pour la fabrication de barres coniques

Country Status (1)

Country Link
EP (1) EP0054343B1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4800744A (en) * 1986-09-11 1989-01-31 Kabushiki Kaisha Kobe Seiko Sho Production of a taper rod
EP0765698B1 (fr) * 1995-09-14 1998-07-08 Benteler Ag Procédé de fabrication d'éléments de construction métalliques à épaisseur de paroi différent

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1752609A1 (de) * 1968-06-21 1971-06-03 Brueninghaus Gmbh Stahlwerke Verfahren und Vorrichtung zur kontinuierlichen Herstellung konischer Metallstaebe

Also Published As

Publication number Publication date
EP0054343A3 (en) 1982-07-21
EP0054343A2 (fr) 1982-06-23

Similar Documents

Publication Publication Date Title
US4842818A (en) Method for manufacturing tapered rods
CN100564549C (zh) 用于钢材热机处理的方法
US20110017368A1 (en) Steel Material, Process of Fabricating Steel Material, and Apparatus of Fabricating Steel Material
US4872923A (en) Die-less drawing method and apparatus
US20220074008A1 (en) Method and system of manufacturing coiled tubing
US4088511A (en) Steels combining toughness and machinability
CN101001705A (zh) 通过温热控制轧制引入大的应变的金属线材，及其制造方法和制造装置
US4040872A (en) Process for strengthening of carbon steels
EP0054343B1 (fr) Procédé et dispositif pour la fabrication de barres coniques
US4604145A (en) Process for production of steel bar or steel wire having an improved spheroidal structure of cementite
US20070074792A1 (en) Method for producing helical springs or stabilizers
SK134297A3 (en) Method of manufacturing hot-worked elongated products, in particular bar or pipe, from high-alloy or hypereutectoid steel
JPS6312690B2 (fr)
JP4018331B2 (ja) ダブルテーパ鋼線と、その連続熱処理方法および装置
CN117120639A (zh) 连续退火设备、连续退火方法、冷轧钢板的制造方法和镀覆钢板的制造方法
JPS6032529B2 (ja) テ−パ−材の製造方法並びにその装置
JPH06346146A (ja) 冷間成形コイルばね用線材の製造方法と装置
CN110512056A (zh) 一种连续退火炉过时效段带钢加热方法
JPH07268463A (ja) 伸線強化高強度鋼線用線材の製造方法
CN109943703A (zh) 用于制造连续管的方法和系统
JP2002282982A (ja) ダブルテーパばね鋼線の製造方法と装置
DE3110043C2 (fr)
JP2002285231A (ja) 部分的に加熱制御する誘導加熱による鋼材の熱処理方法と装置
SU567762A1 (ru) Способ автоматического управлени нагревом трубных заготовок
JPS63157835A (ja) バネ用鋼

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Designated state(s): AT BE CH GB IT LU NL SE

AK Designated contracting states

Designated state(s): AT BE CH GB IT LU NL SE

17P Request for examination filed

Effective date: 19820618

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: DAIDOTOKUSHUKO KABUSHIKIKAISHA

ITF It: translation for a ep patent filed

Owner name: ING. A. GIAMBROCONO & C. S.R.L.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): AT BE CH GB IT LI LU NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19840815

Ref country code: CH

Effective date: 19840815

Ref country code: BE

Effective date: 19840815

REF Corresponds to:

Ref document number: 8970

Country of ref document: AT

Date of ref document: 19840915

Kind code of ref document: T

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19840930

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19840930

Year of fee payment: 4

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19860930

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19870930

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19880915

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19880916

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19890401

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19910802

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19920915

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19920915

EUG Se: european patent has lapsed

Ref document number: 81304219.9

Effective date: 19890614