CA2140310A1 - Process for treating steel edges for skis or the like - Google Patents
Process for treating steel edges for skis or the likeInfo
- Publication number
- CA2140310A1 CA2140310A1 CA002140310A CA2140310A CA2140310A1 CA 2140310 A1 CA2140310 A1 CA 2140310A1 CA 002140310 A CA002140310 A CA 002140310A CA 2140310 A CA2140310 A CA 2140310A CA 2140310 A1 CA2140310 A1 CA 2140310A1
- Authority
- CA
- Canada
- Prior art keywords
- plasma
- cathode
- steel
- running edge
- steel running
- 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.)
- Abandoned
Links
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
- C21D9/20—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for blades for skates
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63C—SKATES; SKIS; ROLLER SKATES; DESIGN OR LAYOUT OF COURTS, RINKS OR THE LIKE
- A63C11/00—Accessories for skiing or snowboarding
- A63C11/04—Accessories for skiing or snowboarding for treating skis or snowboards
- A63C11/06—Edge-sharpeners
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
-
- 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
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
-
- 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
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
- C21D9/06—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails with diminished tendency to become wavy
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Arc Welding In General (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Process for the processing of steel edges for skis or the like wherein the steeledge is rapidly heated at least in part, preferably at least in the region of the edge forming the outer limit of the running surface of the ski, thereafter beingrapidly cooled again and thereby hardened. In order to provide a process which is insensitive in relation to surface properties and which in an economic mannerprovides an accurately defined partial hardening of steel edges of skis or the like in a longitudinal section of optional length and in a reliable manner, an energybeam E is employed for rapid heating, preferably a plasma beam of which the energy at any instance is accurately defined and thereafter the material is preferably merely cooled. The plasma head 9 for the hardening of the edges of steel materials, in particular for carrying out the process, includes a casing 13, 14 sub-divided by insulating material 15, means for the introduction of a gas, around rod-shaped cathode 18 around which flows the gas and an anode 20, 20' surrounding one end of the cathode, having an aperture 21, 21' for the emission of the plasma beam E, a bush 22, preferably of insulation material and having radial bores 27 being provided around the cathode 18 for feeding the gas, which bush leaves an annular gap 23 around the cathode.
Description
Background of the Invention and Prior Art The invention relates to a process for the treatment of steel edges for skis or the like, wherein the steel edges are rapidly heated at least in part, preferably atleast in the region of that edge which forms the outer limit of the running surface of the ski, thereafter being rapidly cooled again.
In order to improve the wearing properties of steel edges, in particular in the case of skis, a maximum hardness of the material would be desirable.
However, if the entire profile forming the steel edge is appropriately hardened,its resiliency is simultaneously impaired to an unacceptable degree. For that reason it has already been proposed in AT-PS 286 152 to provide the ski with steel edges which are hardened only in part, that is to say in the region of maximum wear, i.e. the lower edge which in relation to the running surface is outermost. This conversion of the material of the steel edge into a fine grainedextremely hard and tough martensite texture takes place by rapid heating, rapid chilling and subsequent additional energy application. Purely by way of example a plasma burner is mentioned to serve as the energy source for the extremely fast heating of the material, even though no indications whatsoever are to be found there how a uniform and/or accurately defined hardening in an accurately defined region of the steel edge is to be attainable. In fact, the conventional plasma burners are not suitable for hardening steel edges of skis in the required, accurately definable manner over the entire length, for which reason, in spite of the fast developments of ski production technologies and theobvious advantage of partially hardened steel edges, this particular technology has not been adopted by the industry and has to date not been employed.
Nevertheless, for the hardening of cutting edges of saws, knives or punching tools the employment of plasma burners is known, for example from AT-PS 392 483.
21~0310 Objects and General Description of the Invention Accordingly it is the object of the present invention to provide a process whichcan reliably ensure in an economical manner the accurately defined partial hardening of steel edges of skis or the like over a length of optional magnitude.
Further objects are an accurately defined partially hardened steel edge, a ski equipped with such steel edge and a plasma head for the manufacture of an accurately defined partially hardened steel edge.
For the attainment of the first object it is provided in accordance with the invention that for the said rapid heating an energy beam is employed which at any instant has accurately defined energy whereafter the material is subjected to cooling, preferably exclusively subjected to cooling. Provided the means for generating the energy beam is accurately guided in relation to the steel edge, an obvious prerequisite, this feature ensures an accurately defined energy input inan accurately pre-determinable region of the steel edge. This feature permits anaccurate definition, on the one hand of the heating rate and - as a function of the material yet accurately pre-determinable - the region which is embraced by the hardening procedure. This is also an important prerequisite for the hardenability of steel edges which have already been fitted to the ski. In thoseinstances it must be ensured that the heating of the steel edge material is not too strong, causing heating of the adjoining material of the ski itself above a certain minimum temperature. Otherwise the material of the ski would suffer damage, connections would be loosened or released, adhesives, for example for fixing the steel edge in the ski, would be released or similar effects. Due to the treatment according the invention with a beam which impacts at any instant with an accurately defined energy the material heating can be controlled accurately and unacceptable overheating can be avoided.
Advantageously, according to a further feature of the invention, a plasma beam is employed as the energy beam. Plasma beams entail a particularly favourable 2~0310 energy-cost relationship and are insensitive in relation to surface properties of the material to be treated, such as for example, colour, dirt deposits, reflectivity. Moreover, when using plasma burners, no protective gas is needed. Finally, in the case of a plasma beam, the temperature distribution in axial direction is substantially flatter than in the case of a laser beam, so that for accurate positioning it is not necessary to employ such expensive installations as would be needed with a laser where an accurate adjustment of the focal point is a strict requirement.
If the plasma beam and the steel edge are moved in relation to one another in the longitudinal direction of the steel edge with the plasma beam always having exactly the same energy at least over a partial region of the length of the steel edge, preferably brought about by feeding the plasma head throughout with exactly the same current strength, a uniform exactly defined hardening of the steel edge over the entire length of the longitudinal region covered, is ensured.
This ensures that during any subsequent post-treatment of the steel edge, for example during uniform grinding down, the same material properties apply along the entire hardened length of the steel edge without hardened and non-hardened sections appearing in unpredictable sequence in an undesirable manner. It is inherent in the feature that the plasma beam always has exactly the same energy that at each locality of the plasma beam at each instant exactlythe same temperature always prevails, i.e. the temperature distribution in the - plasma beam remains constant.
On the other hand if an accurately defined distribution of hardened and non-hardened regions or regions of differently intense hardening - both with regard to material hardness, as well as depth or volume of the hardened region -is desired, this can be attained in an advantageous manner in that the plasma beam and the steel edge are moved in relation to one another in the longitudinaldirection of the steel edge, in the course of which the plasma beam, at least over a partial region of the length of the steel edge comprises a preferably evenly modifiable energy, this being preferably attained by an even variation of the current strength fed to the plasma head. Variable energy in this context denotesthat the temperature at each locality of the plasma beam is varied in analogous manner and in an accurately predictable or predeterminable manner.
According to a further feature of the invention a laser beam is employed as an s energy beam and the steel edge, as well as the laser beam are moved in relation to one another.
In order to cover the greatest possible range of localities subjected to wear in a simple and time effective manner, the energy beam, preferably the plasma beam, is aimed simultaneously on to both outer sides of the steel edge and the axis of the beam is preferably aimed on to both outer sides, in particular in a range of 25 about the angular bisectrics, more particularly exactly in the angular bisectrics. Depending on the angle of the beam and/or its parallel displacement in an upward or downward direction in relation to the bisectrics ofthe outer edge to be hardened, a symmetrical or non-symmetrical hardening zone and thereby an adaptation to special wear situations or fields of employment may be attained. A symmetrical hardening zone of the outer edge, the configuration of which is preserved for as long as possible, even then subjected to further processing is attainable if the energy and preferably the plasma beam is caused to coincide preferably exactly with the bisectrics of the outer edge.
A particularly advantageous modification of the process according to the invention provides that a steel edge already mounted on a ski is rapidly heated by means of the energy beam and the region surrounding the impact region of the energy beam is sufficiently cooled so that in the transitional region between 2 s the steel edge and the ski the release temperature of the adhesive fixing the steel edge to the ski body is not exceeded. The hardening of steel edges may then be provided as the final process step in the ski production, because no impairment of other ski components occurs as a result of the hardening according to the invention so that no further post-treatment steps are necessary. Accordingly 21~0310 -even the already installed steel edges are not subjected to any mechanical effects, nor any risk of damage nor any functional impairment as would be the case if hardening were to take place prior to fitting to the ski. The heating ofthe material of the ski in the regions surrounding the steel edge contributes toauto-quenching of the region heated by the energy beam by virtue of heat dissipation and thus contributes to the hardening process so that less thermal energy need be withdrawn by different more expensive and costly means. In this context care need be taken that the temperature does not rise to much that the adhesive employed for fixing the steel edges is released or decomposed.
In order to be able with a given means for generating the energy beam, preferably a given laser or plasma head to cover a larger region of the steel edges, a further feature of the invention provides that the impact region of theenergy beam in the longitudinal direction of the steel edge is broadened at least in a virtual manner, preferably by electromagnetic deflection of the plasma beam. This means that rather than the diameter of the plasma beam itself being increased, which might result in interference with parameters absolutely required for uniform temperature and energy distribution, there is brought abouta kind of undulatory movement of the impact point at a high frequency or a kind of "flutter movement" of the impact point about a central axis during the relative movement of the plasma head and steel edge, causing a region to be covered, which is greater than that corresponding to the cross-section of the plasma beam. In this context the virtual broadening may proceed in one or any desirable direction normal to the axis of the plasma beam. Besides the possibility to cover a larger region starting from the lower outer edge of the steel edge on both outer sides due to the virtual broadening of the plasma beam,this modification also offers the advantage of slightly slowing down the very rapid heating up of the material due to the plasma beam as a result of the distribution of the energy and thereby, if required to a attain a lesser hardness than would correspond to the energy of the plasma beam. Since the region available for the virtual broadening along the outer edges of the steel edges isusually limited and since only a hardening in a narrow region about the wear exposed edge is desired, it is preferred for the broadening to take place in thelongitudinal direction of the steel edge.
The virtual broadening may of course also be applied to the modification involving laser beams, wherein for example by a pivotal lens system the point ofimpact may be varied in the manner described above for plasma beams. A
broadening may also, in the case of a laser beam, be attained by defocussing.
Apart from the virtual broadening which because of the equipment needed therefore is somewhat more complicated and expensive, it is also possible, according to a further inventive feature, to broaden the physical cross section of the energy beam itself, preferably in the direction of the longitudinal direction of the steel edge. In this manner a distribution of the energy input over a larger surface and yet in a very narrow region about the actual edge of the steel edge to be hardened is possible.
A feature which is particularly significant for the uniformity of the energy discharge by the plasma head is that the gas flow around the cathode of the plasma head is kept in a laminar state. Using a laminar flow the temperature distribution in the plasma beam is particularly accurately defined in the desired manner at each locality. However, the additional advantage arises that the igniting of the plasma head can be brought about by a sine impulse, so that in the event of little or simple screening any surrounding electronic components are not affected by the plasma head. This is of particular significance in the context of automatised performance of the process according to the invention with the aid of industrial robots or similar micro processor controlled installations.
A further subject of the invention is a steel edge for skis or the like, partially hardened according to a process as described in the preceding paragraphs.
Particularly by employing the plasma beam for hardening it is possible to attaina particularly penetrating hardening of the steel edge in a very economical 21~0310 manner, particularly in the bisectrics of the outer edge which is subject to wear, resulting in a hardened zone of substantially triangular cross section. Other hardening processes such as for example by using a laser, do not penetrate so deeply so that there results along the outside of the steel edge a hardened zoneof approximately L-shaped cross section which extends only little in depth.
The invention also relates to a ski provided with an at least partially hardenedsteel edge which has been produced according to the process described in any one of the preceding paragraphs.
The invention further relates to a plasma head for the hardening of edges applied 10 to steel materials, in particular for carrying out the process according to any one of the preceding claims, comprising a casing partitioned by insulating material,means for feeding a gas, a cathode of round rod shape around which the gas flows and an anode surrounding an end of the cathode comprising an aperture for the exit of the plasma beam. This plasma head, according to the invention, 15 is characterised by a bush surrounding the cathode provided with radial boresfor feeding the gas, preferably made of insulating material, which bush leaves open an annular gap around the cathode. The inside of the bush jointly with the outside of the cathode defines an annular inlet and uniformising region for the gas of the plasma burner which enhances the setting up of a laminar flow which 2 o is important for the uniformity of the plasma beam.
Particularly favourable results have been attained if, according to an advantageous feature of the invention, the annular gap left open between the bush and the cathode has a ratio of height to width of substantially 2:1.
According to a further feature of the invention, the plasma head is characterised 25 by a tungsten-zirconium cathode. This material provides a uniform discharge between the cathode and anode and resulting therefrom a uniform temperature and energy distribution in the emerging plasma beam.
Once again having regard to the laminarity of the gas flow, it was found to be particularly advantageous, if at least one end of the cathode tapers at an anglebetween 10 and 30, preferably 20. This very small angle which is measured between the symmetrically mutually opposing sides of the preferably radially symmetrical cathode ensures a gentle taper of the cathode towards the tip, whereby the flow of the gas is kept laminar and the plasma beam remains uniform.
However, advantageously the cathode terminates in a blunt configuration, preferably in a plane surface normal to the axis of the cathode. This embodiment of the cathode end permits an optimal separation of the gas flow at the end of the cathode with minimum effect on the laminar flow characteristics.
According to a further feature of the invention, the aperture in the anode takesthe form of an elongate hole of which preferably the longer diameter extends in the longitudinal direction of the steel edge. This configuration of the outlet aperture for the plasma beam from the plasma head effects a physical broadening of the plasma beam in the direction of the longer diameter and thus adistribution of the energy over a larger region of the steel edge, preferably over a longitudinal region thereof. This involves a slower heating of the material which - if desired - results in a lesser hardness of the partially hardened part of the steel edge.
In the alternative or in addition to the above mentioned feature, for att~ining the same effect, means are provided, according to a further feature of the invention, for the electromagnetic deflection of the plasma beam in the region of the outlet aperture for the plasma beam.
The invention also relates to an apparatus for hardening the edges of steel materials, in particular for carrying out the process according to the invention, comprising at least one laser or plasma head, preferably two laser or plasma heads, as described in one of the preceding paragraphs, as well as means for 21~0310 -guiding the or each laser or plasma head and the steel edge or the ski provided with a steel edge to be hardened, as the case may be, in relation to one anotherin the longitll-lin~l direction of the steel edge.
According to a further feature of the invention, the appalaLus is preferably 5 char~tPriced by preferably liquid cooling bodies, preferably of copper, conducted at a distance from the steel edge or the ski body preferably at a distance of 0,2 to 0,3 mm. The cooling bodies ~ ir~tP the amount of heat which can no longer be absorbed by the ski body without a predetermined Le~ ;ldlllre, preferably the release lelllpeldlule of the adhesive fixing the steel l o edges, being exceeded. The use of water at a m~imllm of about 20C as the cooling liquid was found to be the most advantageous solution and copper is the most advantageous selection of material for the m~mlf~ctllre of the cooling bodies for the rapid dissipation of relatively large amounts of heat. In order to avoid impairment of or damage to the surface of the steel edges and/or the ski, 15 the cooling bodies are not applied directly to the steel edge and the surface of the ski and pass in contact along these, but are passed at a small distance fromthe steel edge and/or the ski.
In the following description the invention is to be further explained by way of a non-limiting example with reference to the accolllpallying drawings.
2 o Brief D~ lions of the drawin~c In this context Figure 1 represents a side view and Figure 2 a plan view onto ana~ dlus according to the invention for the hardening of steel edges already fitted to the ski and wherein for purposes of clearer illustration of the guide means, the means for genPr~ting the energy beam have been omitted, Figure 3 2 5 represents an elevation of the a~dLus according to Figures 1 or 2 in the plane m-m of these illustrations, each with a plasma head inclu~ling positioning means on both sides of the ski, Figure 4 represents the det~iled section VI of Figure 3 on an enlarged scale, Figure 5 is a section through an embodiment of a plasma head according to the invention and Figures 6 and 6b r~lesellt an 30 advantageous embodiment of an anode for inct~llation in a plasma head in section and in front elevation respectively.
214031~
Descl;lJlion of specific embo~lim~ntc Three guide means 2 for the ski (not illustrated) are provided on a basic structure denoted as 1, which in a preferably automatisable manner known per se ensures the lateral guidance of the ski in an accurate manner, i.e. accurate to 5 a tenth of a millimetre. On both sides of the transport path of the ski adjustable guide rolls 3 are provided for that purpose. The ski to be treated is conveyed through the plant by means of a conveyor belt 4, set into motion by a drive pulley Sa driven by an accurately adjustable motor S. For this purpose the conveyor belt 4 passes about the deflecting rollers 6a to 6f and is so designed,10 that by fnction an adherent coMection is brought about, preferably with the running surface of the ski.
The two rollers 7 and 8 are provided for the accurate level m~inten~nce of the ski, i.e. normal to the plane within which the ski is guided by the guide rolls 3.
The lower support roll 7, on which the ski rests with its running surface, is 15 pivotally mounted on a shaft fixed st~tion~nly or at least adapted to be accurately fixed, composed of very hard m~t~ri~l, preferably steel. The ski is pressed against the lower support roll 7 by the uppermost pressure roll 8 of which at least the periphery is provided with a relatively soft resilient coating 8a such that in particular also the pretensioning of the ski in its central region -2 0 which causes the arching of the ski between its front and rear lines of support -must be overcome. Simult~neously with the pressing onto the support roll 7, caused by the pretensioning, a ~les~ul~ of the ski is applied onto the conveyor belt 4 which pleS~Ure contributes to the formation of the frictional adhesion based on the friction between the running surface and the conveyor belt 4. The 2s ~l`e~ Ule roll 8 is level adjustable, and optionally movable normal to the ski against spring loading in order to permit the unhindered passage of the tip of the ski and the insertion into or removal from the a~ala~us of the latter.
In Figure 3 the ski is denoted as S, being already fitted with the steel edge K
which is to be hardened and which is pressed by the pressing down roll 8 onto 21~0311~
the support roll 7. On each of both sides of the ski S a means 9 is provided forgenerating the energy beam for heating the respective steel edge K, since this permits a more rapid and therefore more economical processing than with the likewise possible provision of one means 9 only on one side of the ski S. The means 9 are carried on support structures 10, preferably micro processor controlled robot arms, these support structures 10 preferably - as symbolised bythe arrows in the lower portion - being movably mounted in a controlled manner parallel to the axis of the support roll 7. This movability is necessary in order to m~int~in the means 9 in a simple manner, requiring movement in one direction only, at an accurately m~int~ined constant distance from the steel edge K, regardless of the configuration of the ski S. Thus the laser or plasma head 9can follow any optional cross sectional reduction or other configuration of the ski S. The following preferred data were found for att~ining optimum results with the plasma head described further below: distance of the means 9, here specifically the outlet nozzle of the plasma beam, from the steel edge K: 1 to 10 mm; relative velocity of the steel edge K and the means 9 in the longitudinal direction of the edge K: 2 to 8 m/min. It applies to both laser as well as plasma beams, that the ~ in~ble hardness increases with an increase in the relative velocity, because in that case quenching takes place more rapidly. For this purpose a quenching of the material by a cooling medium is not necessary - in fact in the case of steel edges for skis this would result in hardness values which are too high and edges which are too brittle - but cooling (self quenching) by ambient conditions is adequate for ~tt~ining the desired hardening. Thus in the case of CK60 steel values in excess of 50 Rockwell are attainable, these values in the case of steel edges for skis being preferably selected between 58 and 60 Rockwell by suitable adaptation of all process parameters.
The control of the above described movement proceeds by way of the contact rolls 11 which are likewise provided on each support structure 10, these contactrolls 11 being monitored by suitable sensors, the support structures 10 being soacted upon that the contact rolls 11 always bear against the steel edge K with the same pressure. For the sake of greater clarity only one contact roll 11 is drawn in Figure 3 on the left hand side of the ski S in order to permit showing on theright hand side the detail IV illustrated on a larger scale in Figure 4, clearly in conjunction with the support structure 10 and the apparatus as a whole.
This detail IV shows liquid-cooled cooling bodies 12 which protect the material of the components of the ski S surrounding the edge K against too much heating by energy beam E of the means 9. The cooling liquid, preferably water, at a maximum temperature of about 20C flows, for this purpose, through the passages 12a in the cooling bodies 12 which are preferably made of copper.
These cooling bodies 12 cover a longitudinal region of several centimetres up toabout 30 cm preceding and beyond the region of impact of energy beam E. As is clearly shown in Figure 4 the cooling bodies 12 which are likewise carried bythe support structure 10 are not in contact with the ski S or the edge K, but are in each case at a distance therefrom, preferably between 0,2 to 0,3 mm so that in spite of damage to or deterioration of the materials being avoided, for example by scratching, the adequate heat dissipation is nevertheless ensured.
Although the employment of laser beams as an energy beam E is possible, the use of plasma beams is nevertheless preferred, since these are less sensitive tothe surface properties of the edge K and are also more economical in addition tonot requiring additional protective gas. In Figure 5 there is accordingly shown a preferred working example of a plasma head as a means 9 for generating the energy beam E and is to be further described in what follows.
The illustrated plasma head 9 comprises a bi-partite casing including an upper portion 13 and a lower portion 14, which portions 13 and 14 are electrically insulated from one another by a body of insulating material 15. One connecting element 16 and 17 respectively fitted to the upper portion 13 and the lower portion 14 are provided for the feeding and withdrawal of cooling medium for the plasma head 9 by way of the passage 17. In the upper portion 13 a cathode 18 can be fixed interchangeably in a manner known per se in a conventional mounting 19. In the lower portion 14 an anode 20 having an outlet aperture 21 21~0310 for the ionised gas, i.e. the plasma beam, is provided surrounding the free end of the cathode 18 at a distance therefrom. Between the mounting 19 of the cathode 18 and the anode 20, substantially at the same level as the insulating material 15, a bush 22, likewise of insulating material, preferably of ceramic material, is provided, surrounding the cathode 18 at a distance therefrom, so that between the inner periphery of this bush 22 and the cathode 18 an annular space 23is defined. On one side this space is closed by the mounting 19 of the cathode 18 whereas on the opposite side it is continued to form the annular gap 24 between the cathode 18 and the anode 20 and in addition the outlet aperture 21. The gas which is to be ionised is passed through a duct 25 - entering the plasma head 9 in front of or behind the section plane into an annular gap 26 around the bush 22 and furthermore through radial bores 27 into the inlet and uniformising space 23.
Helium or nitrogen, preferably however argon, in an amount of 0,5 to 5 I/min is used as the gas which is to be ionised, a particularly stable plasma simultaneously having protective gas action being attained with argon.
A laminar flow of the gas along the cathode 18 is of particular importance for the uniform energy of the plasma beam. Accordingly, a laminar gas flow is generated due to the uniformation of the flow of the feed gas in the space 23 and due to the preferred ratio thereof of axial height to width of the annular gap of about 2:1, flowing towards to the tip of the cathode 18. The tip of the cathode 18 tapers with a very small angle ~ between 10 and 30, preferably 20, in order to keep the flow as nearly as possible in a laminar condition. A further feature, serving to conduct the gas flow onwards in a laminar state, resides in a plane terminal surface 28 preferably having a diameter of 0,3 mm and being in normal orientation to the axis of the cathode 18, serving as a kind of separation edge for the controlled separation of the gas flow from the cathode 18.
The laminar flow of the gas, besides the uniform energy of the plasma beam and in conjunction with the special material selected for the cathode 18 offers the 21~0310 additional advantage that the ionised discharge between the cathode 18 and the anode 20 does not require an abrupt rectangular pulse, but can be ignited by a soft sinus pulse. This eliminates all screening problems of the plasma head 9 and it can be used without interfering with surrounding electronic components such as those in the controls of the support structure 10, in measuring means etc. During the stable operating phase of the plasma burner the currency strength amounts to between 20 and 180 A. The yield of the energy beam amounts preferably to between 1 and 5 kW, in particular 2 kW per unit 9.
In order to avoid producing too much hardness in the hardened steel edge whereby it would become too brittle, the energy input can be distributed by the energy beam E over a larger region of the steel edge K. Besides virtual broadening due to the deflection of the energy beam E during the relative movement in relation to the steel edge K, for example in the case of a plasma beam by an electromagnet 29 surrounding the outlet aperture 21 or in the case of a laser beam by pivotable lens systems, it is also possible to broaden the physical cross section of the beam itself.
Thus, it is possible to provide instead of the anode 20 of the plasma head 9 having a circular outlet aperture 21, preferably having a diameter of 0,5 to 3 mm, an anode 20', designed in accordance with Figures 6a and 6b, having an elongate hole or oval shape of sizes from 0,6 x 2 mm to 2,5 x 5 mm, preferably 1 x 3 mm. In this context the outlet aperture 21' in order to avoid a too rapid cooling of the material of the steel edge is so orientated that the longer diameter is positioned parallel to the longitudinal axis of the steel edge K. The heating up and quenching accordingly proceeds more slowly and the hardness remains in the range desired for this special application of 57 to 60 Rockwell. Round outlet apertures in the anode because of the more rapid cooling will in any event result in greater hardnesses.
Although in this specification the hardening of edges already fitted to a ski has been explained in more detail by way of example, it is obviously possible with 21~0310 suitable design of the means for bringing about the relative movement between the steel edge to be hardened - more specifically by way of guide and transport means specially adapted to the smaller dimension and rigidity of the steel edge -and the unit for generating the energy beam to also harden the steel edge prior to its assembly with the rem~ining components of the ski in the manner according to the invention and as stated in the introduction to the specification.
In all of the above described procedures, it is advantageously possible for the energy beam E being directed in relation to both outer surfaces of the steel edges K to be hardened, at an incline to the latter. Preferably the beam E is directed onto the outer edge to be hardened of the steel edge K in the manner illustrated in Figure 3 or more clearly in Figure 4 in a range of about 25 about the plane of symmetry, advantageously exactly in the plane of the angle bisectrics. This allows the configuration of the hardened region within the steel edge to be influenced, the greatest hardening penetration being attained in the direct extension of the energy beam E. The hardening penetration decreases, the greater the radial distance is to the axis of the energy beam E. The just mentioned effects arise in a particularly pronounced manner in the case of a plasma beam, whereas they can be attained to a small degree only by the low depth effect of a laser beam. In the case of a laser beam a sweeping of both side surfaces is necessary in somewhat more complex manner in order to cover a surface area region of similar magnitude as in the case of the plasma beam, inspite of which, particularly in the actual edge region, the depth of hardening does not attain that of the plasma beam.
The claims which follow are to be considered an integral part of the present disclosure. Reference numbers (directed to the drawings) shown in the claims serve to facilitate the correlation of integers of the claims with illustrated features of the preferred embodiment(s), but are not intended to restrict in anyway the language of the claims to what is shown in the drawings, unless the contrary is clearly apparent from the context.
What we claim is:
In order to improve the wearing properties of steel edges, in particular in the case of skis, a maximum hardness of the material would be desirable.
However, if the entire profile forming the steel edge is appropriately hardened,its resiliency is simultaneously impaired to an unacceptable degree. For that reason it has already been proposed in AT-PS 286 152 to provide the ski with steel edges which are hardened only in part, that is to say in the region of maximum wear, i.e. the lower edge which in relation to the running surface is outermost. This conversion of the material of the steel edge into a fine grainedextremely hard and tough martensite texture takes place by rapid heating, rapid chilling and subsequent additional energy application. Purely by way of example a plasma burner is mentioned to serve as the energy source for the extremely fast heating of the material, even though no indications whatsoever are to be found there how a uniform and/or accurately defined hardening in an accurately defined region of the steel edge is to be attainable. In fact, the conventional plasma burners are not suitable for hardening steel edges of skis in the required, accurately definable manner over the entire length, for which reason, in spite of the fast developments of ski production technologies and theobvious advantage of partially hardened steel edges, this particular technology has not been adopted by the industry and has to date not been employed.
Nevertheless, for the hardening of cutting edges of saws, knives or punching tools the employment of plasma burners is known, for example from AT-PS 392 483.
21~0310 Objects and General Description of the Invention Accordingly it is the object of the present invention to provide a process whichcan reliably ensure in an economical manner the accurately defined partial hardening of steel edges of skis or the like over a length of optional magnitude.
Further objects are an accurately defined partially hardened steel edge, a ski equipped with such steel edge and a plasma head for the manufacture of an accurately defined partially hardened steel edge.
For the attainment of the first object it is provided in accordance with the invention that for the said rapid heating an energy beam is employed which at any instant has accurately defined energy whereafter the material is subjected to cooling, preferably exclusively subjected to cooling. Provided the means for generating the energy beam is accurately guided in relation to the steel edge, an obvious prerequisite, this feature ensures an accurately defined energy input inan accurately pre-determinable region of the steel edge. This feature permits anaccurate definition, on the one hand of the heating rate and - as a function of the material yet accurately pre-determinable - the region which is embraced by the hardening procedure. This is also an important prerequisite for the hardenability of steel edges which have already been fitted to the ski. In thoseinstances it must be ensured that the heating of the steel edge material is not too strong, causing heating of the adjoining material of the ski itself above a certain minimum temperature. Otherwise the material of the ski would suffer damage, connections would be loosened or released, adhesives, for example for fixing the steel edge in the ski, would be released or similar effects. Due to the treatment according the invention with a beam which impacts at any instant with an accurately defined energy the material heating can be controlled accurately and unacceptable overheating can be avoided.
Advantageously, according to a further feature of the invention, a plasma beam is employed as the energy beam. Plasma beams entail a particularly favourable 2~0310 energy-cost relationship and are insensitive in relation to surface properties of the material to be treated, such as for example, colour, dirt deposits, reflectivity. Moreover, when using plasma burners, no protective gas is needed. Finally, in the case of a plasma beam, the temperature distribution in axial direction is substantially flatter than in the case of a laser beam, so that for accurate positioning it is not necessary to employ such expensive installations as would be needed with a laser where an accurate adjustment of the focal point is a strict requirement.
If the plasma beam and the steel edge are moved in relation to one another in the longitudinal direction of the steel edge with the plasma beam always having exactly the same energy at least over a partial region of the length of the steel edge, preferably brought about by feeding the plasma head throughout with exactly the same current strength, a uniform exactly defined hardening of the steel edge over the entire length of the longitudinal region covered, is ensured.
This ensures that during any subsequent post-treatment of the steel edge, for example during uniform grinding down, the same material properties apply along the entire hardened length of the steel edge without hardened and non-hardened sections appearing in unpredictable sequence in an undesirable manner. It is inherent in the feature that the plasma beam always has exactly the same energy that at each locality of the plasma beam at each instant exactlythe same temperature always prevails, i.e. the temperature distribution in the - plasma beam remains constant.
On the other hand if an accurately defined distribution of hardened and non-hardened regions or regions of differently intense hardening - both with regard to material hardness, as well as depth or volume of the hardened region -is desired, this can be attained in an advantageous manner in that the plasma beam and the steel edge are moved in relation to one another in the longitudinaldirection of the steel edge, in the course of which the plasma beam, at least over a partial region of the length of the steel edge comprises a preferably evenly modifiable energy, this being preferably attained by an even variation of the current strength fed to the plasma head. Variable energy in this context denotesthat the temperature at each locality of the plasma beam is varied in analogous manner and in an accurately predictable or predeterminable manner.
According to a further feature of the invention a laser beam is employed as an s energy beam and the steel edge, as well as the laser beam are moved in relation to one another.
In order to cover the greatest possible range of localities subjected to wear in a simple and time effective manner, the energy beam, preferably the plasma beam, is aimed simultaneously on to both outer sides of the steel edge and the axis of the beam is preferably aimed on to both outer sides, in particular in a range of 25 about the angular bisectrics, more particularly exactly in the angular bisectrics. Depending on the angle of the beam and/or its parallel displacement in an upward or downward direction in relation to the bisectrics ofthe outer edge to be hardened, a symmetrical or non-symmetrical hardening zone and thereby an adaptation to special wear situations or fields of employment may be attained. A symmetrical hardening zone of the outer edge, the configuration of which is preserved for as long as possible, even then subjected to further processing is attainable if the energy and preferably the plasma beam is caused to coincide preferably exactly with the bisectrics of the outer edge.
A particularly advantageous modification of the process according to the invention provides that a steel edge already mounted on a ski is rapidly heated by means of the energy beam and the region surrounding the impact region of the energy beam is sufficiently cooled so that in the transitional region between 2 s the steel edge and the ski the release temperature of the adhesive fixing the steel edge to the ski body is not exceeded. The hardening of steel edges may then be provided as the final process step in the ski production, because no impairment of other ski components occurs as a result of the hardening according to the invention so that no further post-treatment steps are necessary. Accordingly 21~0310 -even the already installed steel edges are not subjected to any mechanical effects, nor any risk of damage nor any functional impairment as would be the case if hardening were to take place prior to fitting to the ski. The heating ofthe material of the ski in the regions surrounding the steel edge contributes toauto-quenching of the region heated by the energy beam by virtue of heat dissipation and thus contributes to the hardening process so that less thermal energy need be withdrawn by different more expensive and costly means. In this context care need be taken that the temperature does not rise to much that the adhesive employed for fixing the steel edges is released or decomposed.
In order to be able with a given means for generating the energy beam, preferably a given laser or plasma head to cover a larger region of the steel edges, a further feature of the invention provides that the impact region of theenergy beam in the longitudinal direction of the steel edge is broadened at least in a virtual manner, preferably by electromagnetic deflection of the plasma beam. This means that rather than the diameter of the plasma beam itself being increased, which might result in interference with parameters absolutely required for uniform temperature and energy distribution, there is brought abouta kind of undulatory movement of the impact point at a high frequency or a kind of "flutter movement" of the impact point about a central axis during the relative movement of the plasma head and steel edge, causing a region to be covered, which is greater than that corresponding to the cross-section of the plasma beam. In this context the virtual broadening may proceed in one or any desirable direction normal to the axis of the plasma beam. Besides the possibility to cover a larger region starting from the lower outer edge of the steel edge on both outer sides due to the virtual broadening of the plasma beam,this modification also offers the advantage of slightly slowing down the very rapid heating up of the material due to the plasma beam as a result of the distribution of the energy and thereby, if required to a attain a lesser hardness than would correspond to the energy of the plasma beam. Since the region available for the virtual broadening along the outer edges of the steel edges isusually limited and since only a hardening in a narrow region about the wear exposed edge is desired, it is preferred for the broadening to take place in thelongitudinal direction of the steel edge.
The virtual broadening may of course also be applied to the modification involving laser beams, wherein for example by a pivotal lens system the point ofimpact may be varied in the manner described above for plasma beams. A
broadening may also, in the case of a laser beam, be attained by defocussing.
Apart from the virtual broadening which because of the equipment needed therefore is somewhat more complicated and expensive, it is also possible, according to a further inventive feature, to broaden the physical cross section of the energy beam itself, preferably in the direction of the longitudinal direction of the steel edge. In this manner a distribution of the energy input over a larger surface and yet in a very narrow region about the actual edge of the steel edge to be hardened is possible.
A feature which is particularly significant for the uniformity of the energy discharge by the plasma head is that the gas flow around the cathode of the plasma head is kept in a laminar state. Using a laminar flow the temperature distribution in the plasma beam is particularly accurately defined in the desired manner at each locality. However, the additional advantage arises that the igniting of the plasma head can be brought about by a sine impulse, so that in the event of little or simple screening any surrounding electronic components are not affected by the plasma head. This is of particular significance in the context of automatised performance of the process according to the invention with the aid of industrial robots or similar micro processor controlled installations.
A further subject of the invention is a steel edge for skis or the like, partially hardened according to a process as described in the preceding paragraphs.
Particularly by employing the plasma beam for hardening it is possible to attaina particularly penetrating hardening of the steel edge in a very economical 21~0310 manner, particularly in the bisectrics of the outer edge which is subject to wear, resulting in a hardened zone of substantially triangular cross section. Other hardening processes such as for example by using a laser, do not penetrate so deeply so that there results along the outside of the steel edge a hardened zoneof approximately L-shaped cross section which extends only little in depth.
The invention also relates to a ski provided with an at least partially hardenedsteel edge which has been produced according to the process described in any one of the preceding paragraphs.
The invention further relates to a plasma head for the hardening of edges applied 10 to steel materials, in particular for carrying out the process according to any one of the preceding claims, comprising a casing partitioned by insulating material,means for feeding a gas, a cathode of round rod shape around which the gas flows and an anode surrounding an end of the cathode comprising an aperture for the exit of the plasma beam. This plasma head, according to the invention, 15 is characterised by a bush surrounding the cathode provided with radial boresfor feeding the gas, preferably made of insulating material, which bush leaves open an annular gap around the cathode. The inside of the bush jointly with the outside of the cathode defines an annular inlet and uniformising region for the gas of the plasma burner which enhances the setting up of a laminar flow which 2 o is important for the uniformity of the plasma beam.
Particularly favourable results have been attained if, according to an advantageous feature of the invention, the annular gap left open between the bush and the cathode has a ratio of height to width of substantially 2:1.
According to a further feature of the invention, the plasma head is characterised 25 by a tungsten-zirconium cathode. This material provides a uniform discharge between the cathode and anode and resulting therefrom a uniform temperature and energy distribution in the emerging plasma beam.
Once again having regard to the laminarity of the gas flow, it was found to be particularly advantageous, if at least one end of the cathode tapers at an anglebetween 10 and 30, preferably 20. This very small angle which is measured between the symmetrically mutually opposing sides of the preferably radially symmetrical cathode ensures a gentle taper of the cathode towards the tip, whereby the flow of the gas is kept laminar and the plasma beam remains uniform.
However, advantageously the cathode terminates in a blunt configuration, preferably in a plane surface normal to the axis of the cathode. This embodiment of the cathode end permits an optimal separation of the gas flow at the end of the cathode with minimum effect on the laminar flow characteristics.
According to a further feature of the invention, the aperture in the anode takesthe form of an elongate hole of which preferably the longer diameter extends in the longitudinal direction of the steel edge. This configuration of the outlet aperture for the plasma beam from the plasma head effects a physical broadening of the plasma beam in the direction of the longer diameter and thus adistribution of the energy over a larger region of the steel edge, preferably over a longitudinal region thereof. This involves a slower heating of the material which - if desired - results in a lesser hardness of the partially hardened part of the steel edge.
In the alternative or in addition to the above mentioned feature, for att~ining the same effect, means are provided, according to a further feature of the invention, for the electromagnetic deflection of the plasma beam in the region of the outlet aperture for the plasma beam.
The invention also relates to an apparatus for hardening the edges of steel materials, in particular for carrying out the process according to the invention, comprising at least one laser or plasma head, preferably two laser or plasma heads, as described in one of the preceding paragraphs, as well as means for 21~0310 -guiding the or each laser or plasma head and the steel edge or the ski provided with a steel edge to be hardened, as the case may be, in relation to one anotherin the longitll-lin~l direction of the steel edge.
According to a further feature of the invention, the appalaLus is preferably 5 char~tPriced by preferably liquid cooling bodies, preferably of copper, conducted at a distance from the steel edge or the ski body preferably at a distance of 0,2 to 0,3 mm. The cooling bodies ~ ir~tP the amount of heat which can no longer be absorbed by the ski body without a predetermined Le~ ;ldlllre, preferably the release lelllpeldlule of the adhesive fixing the steel l o edges, being exceeded. The use of water at a m~imllm of about 20C as the cooling liquid was found to be the most advantageous solution and copper is the most advantageous selection of material for the m~mlf~ctllre of the cooling bodies for the rapid dissipation of relatively large amounts of heat. In order to avoid impairment of or damage to the surface of the steel edges and/or the ski, 15 the cooling bodies are not applied directly to the steel edge and the surface of the ski and pass in contact along these, but are passed at a small distance fromthe steel edge and/or the ski.
In the following description the invention is to be further explained by way of a non-limiting example with reference to the accolllpallying drawings.
2 o Brief D~ lions of the drawin~c In this context Figure 1 represents a side view and Figure 2 a plan view onto ana~ dlus according to the invention for the hardening of steel edges already fitted to the ski and wherein for purposes of clearer illustration of the guide means, the means for genPr~ting the energy beam have been omitted, Figure 3 2 5 represents an elevation of the a~dLus according to Figures 1 or 2 in the plane m-m of these illustrations, each with a plasma head inclu~ling positioning means on both sides of the ski, Figure 4 represents the det~iled section VI of Figure 3 on an enlarged scale, Figure 5 is a section through an embodiment of a plasma head according to the invention and Figures 6 and 6b r~lesellt an 30 advantageous embodiment of an anode for inct~llation in a plasma head in section and in front elevation respectively.
214031~
Descl;lJlion of specific embo~lim~ntc Three guide means 2 for the ski (not illustrated) are provided on a basic structure denoted as 1, which in a preferably automatisable manner known per se ensures the lateral guidance of the ski in an accurate manner, i.e. accurate to 5 a tenth of a millimetre. On both sides of the transport path of the ski adjustable guide rolls 3 are provided for that purpose. The ski to be treated is conveyed through the plant by means of a conveyor belt 4, set into motion by a drive pulley Sa driven by an accurately adjustable motor S. For this purpose the conveyor belt 4 passes about the deflecting rollers 6a to 6f and is so designed,10 that by fnction an adherent coMection is brought about, preferably with the running surface of the ski.
The two rollers 7 and 8 are provided for the accurate level m~inten~nce of the ski, i.e. normal to the plane within which the ski is guided by the guide rolls 3.
The lower support roll 7, on which the ski rests with its running surface, is 15 pivotally mounted on a shaft fixed st~tion~nly or at least adapted to be accurately fixed, composed of very hard m~t~ri~l, preferably steel. The ski is pressed against the lower support roll 7 by the uppermost pressure roll 8 of which at least the periphery is provided with a relatively soft resilient coating 8a such that in particular also the pretensioning of the ski in its central region -2 0 which causes the arching of the ski between its front and rear lines of support -must be overcome. Simult~neously with the pressing onto the support roll 7, caused by the pretensioning, a ~les~ul~ of the ski is applied onto the conveyor belt 4 which pleS~Ure contributes to the formation of the frictional adhesion based on the friction between the running surface and the conveyor belt 4. The 2s ~l`e~ Ule roll 8 is level adjustable, and optionally movable normal to the ski against spring loading in order to permit the unhindered passage of the tip of the ski and the insertion into or removal from the a~ala~us of the latter.
In Figure 3 the ski is denoted as S, being already fitted with the steel edge K
which is to be hardened and which is pressed by the pressing down roll 8 onto 21~0311~
the support roll 7. On each of both sides of the ski S a means 9 is provided forgenerating the energy beam for heating the respective steel edge K, since this permits a more rapid and therefore more economical processing than with the likewise possible provision of one means 9 only on one side of the ski S. The means 9 are carried on support structures 10, preferably micro processor controlled robot arms, these support structures 10 preferably - as symbolised bythe arrows in the lower portion - being movably mounted in a controlled manner parallel to the axis of the support roll 7. This movability is necessary in order to m~int~in the means 9 in a simple manner, requiring movement in one direction only, at an accurately m~int~ined constant distance from the steel edge K, regardless of the configuration of the ski S. Thus the laser or plasma head 9can follow any optional cross sectional reduction or other configuration of the ski S. The following preferred data were found for att~ining optimum results with the plasma head described further below: distance of the means 9, here specifically the outlet nozzle of the plasma beam, from the steel edge K: 1 to 10 mm; relative velocity of the steel edge K and the means 9 in the longitudinal direction of the edge K: 2 to 8 m/min. It applies to both laser as well as plasma beams, that the ~ in~ble hardness increases with an increase in the relative velocity, because in that case quenching takes place more rapidly. For this purpose a quenching of the material by a cooling medium is not necessary - in fact in the case of steel edges for skis this would result in hardness values which are too high and edges which are too brittle - but cooling (self quenching) by ambient conditions is adequate for ~tt~ining the desired hardening. Thus in the case of CK60 steel values in excess of 50 Rockwell are attainable, these values in the case of steel edges for skis being preferably selected between 58 and 60 Rockwell by suitable adaptation of all process parameters.
The control of the above described movement proceeds by way of the contact rolls 11 which are likewise provided on each support structure 10, these contactrolls 11 being monitored by suitable sensors, the support structures 10 being soacted upon that the contact rolls 11 always bear against the steel edge K with the same pressure. For the sake of greater clarity only one contact roll 11 is drawn in Figure 3 on the left hand side of the ski S in order to permit showing on theright hand side the detail IV illustrated on a larger scale in Figure 4, clearly in conjunction with the support structure 10 and the apparatus as a whole.
This detail IV shows liquid-cooled cooling bodies 12 which protect the material of the components of the ski S surrounding the edge K against too much heating by energy beam E of the means 9. The cooling liquid, preferably water, at a maximum temperature of about 20C flows, for this purpose, through the passages 12a in the cooling bodies 12 which are preferably made of copper.
These cooling bodies 12 cover a longitudinal region of several centimetres up toabout 30 cm preceding and beyond the region of impact of energy beam E. As is clearly shown in Figure 4 the cooling bodies 12 which are likewise carried bythe support structure 10 are not in contact with the ski S or the edge K, but are in each case at a distance therefrom, preferably between 0,2 to 0,3 mm so that in spite of damage to or deterioration of the materials being avoided, for example by scratching, the adequate heat dissipation is nevertheless ensured.
Although the employment of laser beams as an energy beam E is possible, the use of plasma beams is nevertheless preferred, since these are less sensitive tothe surface properties of the edge K and are also more economical in addition tonot requiring additional protective gas. In Figure 5 there is accordingly shown a preferred working example of a plasma head as a means 9 for generating the energy beam E and is to be further described in what follows.
The illustrated plasma head 9 comprises a bi-partite casing including an upper portion 13 and a lower portion 14, which portions 13 and 14 are electrically insulated from one another by a body of insulating material 15. One connecting element 16 and 17 respectively fitted to the upper portion 13 and the lower portion 14 are provided for the feeding and withdrawal of cooling medium for the plasma head 9 by way of the passage 17. In the upper portion 13 a cathode 18 can be fixed interchangeably in a manner known per se in a conventional mounting 19. In the lower portion 14 an anode 20 having an outlet aperture 21 21~0310 for the ionised gas, i.e. the plasma beam, is provided surrounding the free end of the cathode 18 at a distance therefrom. Between the mounting 19 of the cathode 18 and the anode 20, substantially at the same level as the insulating material 15, a bush 22, likewise of insulating material, preferably of ceramic material, is provided, surrounding the cathode 18 at a distance therefrom, so that between the inner periphery of this bush 22 and the cathode 18 an annular space 23is defined. On one side this space is closed by the mounting 19 of the cathode 18 whereas on the opposite side it is continued to form the annular gap 24 between the cathode 18 and the anode 20 and in addition the outlet aperture 21. The gas which is to be ionised is passed through a duct 25 - entering the plasma head 9 in front of or behind the section plane into an annular gap 26 around the bush 22 and furthermore through radial bores 27 into the inlet and uniformising space 23.
Helium or nitrogen, preferably however argon, in an amount of 0,5 to 5 I/min is used as the gas which is to be ionised, a particularly stable plasma simultaneously having protective gas action being attained with argon.
A laminar flow of the gas along the cathode 18 is of particular importance for the uniform energy of the plasma beam. Accordingly, a laminar gas flow is generated due to the uniformation of the flow of the feed gas in the space 23 and due to the preferred ratio thereof of axial height to width of the annular gap of about 2:1, flowing towards to the tip of the cathode 18. The tip of the cathode 18 tapers with a very small angle ~ between 10 and 30, preferably 20, in order to keep the flow as nearly as possible in a laminar condition. A further feature, serving to conduct the gas flow onwards in a laminar state, resides in a plane terminal surface 28 preferably having a diameter of 0,3 mm and being in normal orientation to the axis of the cathode 18, serving as a kind of separation edge for the controlled separation of the gas flow from the cathode 18.
The laminar flow of the gas, besides the uniform energy of the plasma beam and in conjunction with the special material selected for the cathode 18 offers the 21~0310 additional advantage that the ionised discharge between the cathode 18 and the anode 20 does not require an abrupt rectangular pulse, but can be ignited by a soft sinus pulse. This eliminates all screening problems of the plasma head 9 and it can be used without interfering with surrounding electronic components such as those in the controls of the support structure 10, in measuring means etc. During the stable operating phase of the plasma burner the currency strength amounts to between 20 and 180 A. The yield of the energy beam amounts preferably to between 1 and 5 kW, in particular 2 kW per unit 9.
In order to avoid producing too much hardness in the hardened steel edge whereby it would become too brittle, the energy input can be distributed by the energy beam E over a larger region of the steel edge K. Besides virtual broadening due to the deflection of the energy beam E during the relative movement in relation to the steel edge K, for example in the case of a plasma beam by an electromagnet 29 surrounding the outlet aperture 21 or in the case of a laser beam by pivotable lens systems, it is also possible to broaden the physical cross section of the beam itself.
Thus, it is possible to provide instead of the anode 20 of the plasma head 9 having a circular outlet aperture 21, preferably having a diameter of 0,5 to 3 mm, an anode 20', designed in accordance with Figures 6a and 6b, having an elongate hole or oval shape of sizes from 0,6 x 2 mm to 2,5 x 5 mm, preferably 1 x 3 mm. In this context the outlet aperture 21' in order to avoid a too rapid cooling of the material of the steel edge is so orientated that the longer diameter is positioned parallel to the longitudinal axis of the steel edge K. The heating up and quenching accordingly proceeds more slowly and the hardness remains in the range desired for this special application of 57 to 60 Rockwell. Round outlet apertures in the anode because of the more rapid cooling will in any event result in greater hardnesses.
Although in this specification the hardening of edges already fitted to a ski has been explained in more detail by way of example, it is obviously possible with 21~0310 suitable design of the means for bringing about the relative movement between the steel edge to be hardened - more specifically by way of guide and transport means specially adapted to the smaller dimension and rigidity of the steel edge -and the unit for generating the energy beam to also harden the steel edge prior to its assembly with the rem~ining components of the ski in the manner according to the invention and as stated in the introduction to the specification.
In all of the above described procedures, it is advantageously possible for the energy beam E being directed in relation to both outer surfaces of the steel edges K to be hardened, at an incline to the latter. Preferably the beam E is directed onto the outer edge to be hardened of the steel edge K in the manner illustrated in Figure 3 or more clearly in Figure 4 in a range of about 25 about the plane of symmetry, advantageously exactly in the plane of the angle bisectrics. This allows the configuration of the hardened region within the steel edge to be influenced, the greatest hardening penetration being attained in the direct extension of the energy beam E. The hardening penetration decreases, the greater the radial distance is to the axis of the energy beam E. The just mentioned effects arise in a particularly pronounced manner in the case of a plasma beam, whereas they can be attained to a small degree only by the low depth effect of a laser beam. In the case of a laser beam a sweeping of both side surfaces is necessary in somewhat more complex manner in order to cover a surface area region of similar magnitude as in the case of the plasma beam, inspite of which, particularly in the actual edge region, the depth of hardening does not attain that of the plasma beam.
The claims which follow are to be considered an integral part of the present disclosure. Reference numbers (directed to the drawings) shown in the claims serve to facilitate the correlation of integers of the claims with illustrated features of the preferred embodiment(s), but are not intended to restrict in anyway the language of the claims to what is shown in the drawings, unless the contrary is clearly apparent from the context.
What we claim is:
Claims (37)
1. In a process for the hardening of steel running edges for skis or the like wherein the steel running edge is rapidly heated at least partially, preferably at least in the region of the steel running edge which defines the outer edge of the running surface of the ski, thereafter being rapidly cooled again and hardened thereby, the improvement that for the rapid heating of the region of the steel running edge which is to be hardened a plasma beam is employed, the energy of which at any instant in time is accurately defined.
2. Process as claimed in claim 1, wherein after the material has been heated by the plasma it is merely cooled.
3. Process as claimed in claim 1, wherein the plasma beam and the steel running edge are moved in relation to one another in the longitudinal direction of the steel running edge and the plasma beam in the course thereof, at least over a portion of the length of the steel running edge, constantly yields the same energy.
4. Process as claimed in claim 3, wherein the yield of the same energy is attained by feeding the plasma head always with the same strength of the current.
5. Process as claimed in claim 1, wherein the plasma beam and the steel running edge are moved relative to one another in the longitudinal direction of the steel running edge and the plasma beam, at least over a portion of the length of the steel running edge, provides a variable energy.
6. Process as claimed in claim 5, wherein the plasma beam provides a uniformly variable energy.
7. Process as claimed in claim 6, wherein the uniformly variable energy is attained by the regular variation of the current strength fed to the plasma head.
8. Process as claimed in claim 1, wherein the plasma beam is directed simultaneously onto both outer sides of the steel running edge.
9. Process as claimed in claim 8, wherein the axis of the plasma beam is directed at an incline onto both outer sides.
10. Process as claimed in claim 9, wherein said incline is in a range of 25°
about the angle bisectrics.
about the angle bisectrics.
11. Process as claimed in claim 10, wherein said incline is exactly in the angle bisectrics.
12. Process as claimed in claim 1, wherein the steel running edge which is already fitted to the ski is rapidly heated by means of the plasma beam and simultaneously the region about the region of impact of the energy beam is cooled so much that in the transitional region of the steel running edge and theski a predetermined temperature is not exceeded.
13. Process as claimed in claim 12, wherein the predetermined temperature is the release temperature of the adhesive for fixing the steel running edge to the ski body.
14. Process as claimed in claim 1, wherein the region of impact of the plasma beam in the direction of the longitudinal direction of the steel running edge is broadened at least in a virtual manner.
15. Process as claimed in claim 14, wherein the said virtual broadening is attained by electromagnetic deflection of the plasma beam.
16. Process as claimed in claim 6, wherein the cross section of the plasma ray itself is broadened.
17. Process as claimed in claim 6, wherein said broadening is effected in the direction of the longitudinal dimension of the steel running edge.
18. Process as claimed in claim 1, wherein the gas flow for the plasma beam around the cathode of the plasma head is maintained in a laminar state.
19. Steel running edge for skis and the like which has at least been partially hardened according to a process in accordance with claim 1.
20. Ski comprising at least one steel running edge at least partially hardened in accordance with the process according to claim 1.
21. Plasma head for the hardening of edges of steel materials, in particular for carrying out the process according to claim 1, including a casing (13, 14) sub-divided by a body of insulating material (15), means for feeding a gas, a round rod-shaped cathode (18) around which gas flows and an anode (20, 20') surrounding one end of the cathode (18) having an aperture (21, 21') for the ignition of the plasma beam (E) and further including a bush (22) around the cathode (23) provided with radial bores (27) for feeding the gas, which bush (22) leaves open an annular gap (23) around the cathode (18).
22. Plasma head as claimed in claim 21, wherein the bush is made of insulation material.
23. Plasma head as claimed in claim 22, wherein the annular gap (23) left between the bush (22) and the cathode (18) has a ratio of height to width of about 2:1.
24. Plasma head as claimed in claim 22, comprising a tungsten-zirconium cathode (18).
25. Plasma head as claimed in claim 22, wherein at least one end of the cathode (18) tapers at an angle between 10 and 30°.
26. Plasma head as claimed in claim 25, wherein said angle is about 20°.
27. Plasma head as claimed in claim 22, wherein the cathode (18) terminates in a blunt configuration.
28. Plasma head as claimed in claim 27, wherein said blunt configuration is a plane surface (28) normal to the cathode axis.
29. Plasma head as claimed in claim 22, wherein the aperture (21') in the anode (20') is in the form of an elongate hole.
30. Plasma head as claimed in claim 29, wherein the larger diameter of the elongate hole is directed in the longitudinal direction of the steel running edge (K).
31. Plasma head according to claim 22, wherein means (29) are provided for the electromagnetic deflection of the plasma beam (E) in the region of the outlet aperture (21, 21') for the plasma beam.
32. Apparatus for the hardening of edges of steel materials, in particular for carrying out the process according to claim 1 including at least one plasma or laser head (9) as well as means (2-8, 10) for guiding the or each plasma or laser head (9) and the steel running edge (K) or the ski (S) fitted with a steel running edge which is to be hardened, as the case may be, in relation to one another in the longitudinal direction of the steel running edge (K).
33. Apparatus as claimed in claim 32, comprising a plasma head including a casing (13, 14) sub-divided by a body of insulating material (15), means for feeding a gas, a round rod-shaped cathode (18) around which gas flows and an anode (20, 20') surrounding one end of the cathode (18) having an aperture (21, 21') for the ignition of the plasma beam (E) including a bush (22) around the cathode (23) and provided with radial bores (27) for feeding the gas, which bush(22) leaves open an annular gap (23) around the cathode (18).
34. Apparatus as claimed in claim 32, which includes cooled cooling bodies (12) guided at a distance from the steel running edge (K) respectively the ski body.
35. Apparatus as claimed in claim 34, wherein said distance is about 0,2 to 0,3 mm.
36. Apparatus as claimed in claim 34, wherein the cooling bodies (12) are liquid-cooled.
37. Apparatus as claimed in claim 34, wherein the cooling bodies (12) are made of copper.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA80/94 | 1994-01-17 | ||
| AT0008094A AT404798B (en) | 1994-01-17 | 1994-01-17 | METHOD FOR HARDENING STEEL RUNNERS FOR SKI AND PLASMA HEAD FOR HARDENING EDGES IN STEEL MATERIALS AND DEVICE FOR HARDENING EDGES IN STEEL MATERIALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2140310A1 true CA2140310A1 (en) | 1995-07-18 |
Family
ID=3481006
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002140310A Abandoned CA2140310A1 (en) | 1994-01-17 | 1995-01-16 | Process for treating steel edges for skis or the like |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0667175B1 (en) |
| JP (1) | JPH07250932A (en) |
| AT (2) | AT404798B (en) |
| CA (1) | CA2140310A1 (en) |
| DE (1) | DE59503963D1 (en) |
| SI (1) | SI0667175T1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT403805B (en) * | 1994-12-23 | 1998-05-25 | Fischer Gmbh | METHOD FOR MACHINING STEEL EDGES FOR SKI OR THE LIKE |
| RU2644638C2 (en) * | 2016-01-26 | 2018-02-13 | Общество с ограниченной ответственностью "Транс-Атом" | Method of heat treatment of steel rails |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT286152B (en) * | 1968-08-23 | 1970-11-25 | Boehler & Co Ag Geb | Steel edges for skis |
| US3802927A (en) * | 1970-09-14 | 1974-04-09 | N Gomada | Apex seal for rotary piston engine and method of producing same |
| DE2435446A1 (en) * | 1974-07-23 | 1976-06-16 | Hollingsworth Gmbh | High speed hardening of teeth on saw blade strip - by feeding strip through plasma jet |
| US4317984A (en) * | 1978-07-07 | 1982-03-02 | Fridlyand Mikhail G | Method of plasma treatment of materials |
| JPS60501450A (en) * | 1983-03-25 | 1985-09-05 | ボブロフ アレクサンドル ブラデイミロビツチ | Thermomechanical machining method |
| YU135290A (en) * | 1989-07-25 | 1992-12-21 | Schuler, Albert | HARDENING PROCEDURE FOR CUTTING EDGES OF SAWS, KNIVES AND PUNCHING TOOLS |
| AT392483B (en) * | 1989-07-25 | 1991-04-10 | Schuler Albert | METHOD FOR HARDENING THE CUTTING EDGES OF SAWS |
| DE4000744C2 (en) * | 1990-01-12 | 1996-07-11 | Trumpf Gmbh & Co | Process for steel edges of winter sports equipment |
| DE4042349A1 (en) * | 1990-06-08 | 1991-12-19 | Fraunhofer Ges Forschung | METHOD FOR TREATMENT OF WORKPIECES WITH LASER RADIATION |
| US5313042A (en) * | 1991-06-07 | 1994-05-17 | Nissan Motor Co., Ltd | Laser hardening device |
-
1994
- 1994-01-17 AT AT0008094A patent/AT404798B/en not_active IP Right Cessation
-
1995
- 1995-01-11 AT AT95890006T patent/ATE172381T1/en not_active IP Right Cessation
- 1995-01-11 SI SI9530148T patent/SI0667175T1/en not_active IP Right Cessation
- 1995-01-11 DE DE59503963T patent/DE59503963D1/en not_active Expired - Fee Related
- 1995-01-11 EP EP95890006A patent/EP0667175B1/en not_active Expired - Lifetime
- 1995-01-16 CA CA002140310A patent/CA2140310A1/en not_active Abandoned
- 1995-01-17 JP JP7005082A patent/JPH07250932A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07250932A (en) | 1995-10-03 |
| EP0667175B1 (en) | 1998-10-21 |
| ATA8094A (en) | 1997-09-15 |
| AT404798B (en) | 1999-02-25 |
| SI0667175T1 (en) | 1999-02-28 |
| ATE172381T1 (en) | 1998-11-15 |
| EP0667175A3 (en) | 1996-08-28 |
| EP0667175A2 (en) | 1995-08-16 |
| DE59503963D1 (en) | 1998-11-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |