MX2008006285A - Joint design - Google Patents

Abstract

Disclosed hearer is an electrode joint having a first carbon body (11) having at least one end portion that includes a male tang (20) with a convex tip (22) and a second carbon body (13) having a female socket (30) with a concave base (32).

Description

BOARD DESIGN TECHNICAL FIELD The present invention relates to a carbon body design, for use with electrode joints. More particularly, the invention relates to a unique design for the connecting ends of carbon bodies, which facilitates the mechanical securing of the electrode joints. The background technique Graphite electrodes are used in the steel industry to melt the metals and other ingredients used to form the steel in electrothermal furnaces. The heat needed to melt the metals is generated by passing a current through an electrode or a plurality of electrodes, usually three, and forming an arc between the electrodes and the metal. Frequently electrical currents of more than 100,000 amperes are used. The resulting high temperature melts the metals and other ingredients. In general, the electrodes used in steel ovens are used in electrode columns; that is, a series of individual electrodes joined together to form a single column. In this way, to the extent that the electrodes are depleted during the thermal process, replacement electrodes can be attached to the column, to maintain the length of the column that extends into the furnace.

Conventionally, the electrodes are attached to the columns by means of a pin (sometimes called a nipple) that functions to join the ends of adjacent electrodes. Typically, the pin adopts the form of threaded male sections, opposite, with at least one end of the electrodes comprising female threaded sections, capable of engaging the threaded male section of the pin. Thus, when each of the opposite threaded male sections of a pin are screwed into the threaded female sections at the ends of two electrodes, those electrodes are joined in a column of electrodes. Commonly, the joined ends of the adjacent electrodes and the pin that is between them are referred to in the art as a gasket. Alternatively, the electrodes may be formed with a male threaded or spigot protrusion, machined at one end, and a female threaded receptacle, machined at the other end; so that the electrodes can be attached by screwing the male pin of an electrode into the female receptacle of a second electrode, thereby forming a column of electrodes. The joined ends of two of said adjacent electrodes, in that embodiment, are also referred to in the art as a male-female joint. Given the extreme thermal and mechanical stresses to which the electrode and the joint (and, in reality, the electrode column in its entirety) are subjected, the detachment of the joint and the consequent loss of the column of electrodes under the detached joint , they are a recurring problem.

In so-called jam-free joints, in which the threads of the pin and the electrodes, or the two electrodes in a male-female joint, are only partially joined to the surface of the thread, solutions have been proposed to reduce the tension of the joint by fixing the male and female joint elements together.

One method involves melting pitch or other material so that it infiltrates the area between the threads and carbonizes with the heat of the furnace, which forms a bond between the elements of the joint. For example, in the international application PCT / US2002 / 10125, the inventors Pavlisin and Weber describe a "plug" formed of expandable pitch and graphite. When the plug is placed in the base of an electrode receptacle, the heat from the furnace causes the pitch to melt and the graphite to expand, which forces the pitch melted between the threads, where it carbonizes and secures the meeting. Another seal assurance system, used in the past, had been to provide one or more holes in an electrode pin, at or near each of its ends, and to place the pitch in the holes. Again, the heat of the furnace causes the pitch to melt and flow through the threads, where it carbonizes and secures the gasket in its position. While effective, these prior art methods for securing the seal are most effective only on non-tightened threads, as illustrated in FIG. 5. On fully tightened threads, in which the thread surfaces of an element are in full contact with the thread surfaces of the other element, as illustrated in Figure 4, there is insufficient space between the threads for the pitch or other adherent composition to flow there. Therefore, there is a need to find a way to reduce stresses between joint elements, which works for graphite electrode joints that are fully tightened and not fully tightened. BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a design for the end portions of two carbon bodies, which reduces the tensions between the two carbon bodies. It is an object of the present invention to provide a system for securing a gasket for graphite electrodes. It is another object of the present invention to provide a graphite electrode gasket, which is designed to better withstand the thermal and mechanical stresses that operate on an electrode column during use, compared to the conventional graphite electrode gaskets of the art. previous. It is also an object of the present invention to provide a graphite electrode gasket that produces electrode column gaskets having improved strength and stability. It is also another object of the present invention to provide a graphite electrode gasket having improved resistance to cigarette butt loss, defined as the loss of the part of the electrode column remaining from the tip of the arc (i.e. or the tip of the electrode column that extends to the surface, and from which the arc is formed) to, and sometimes including, the joint closest to the tip of the arc, as compared to the graphite electrode joints conventional techniques. These objectives and others that will become apparent to those who have experience in the matter when reviewing the following description, can be achieved by providing an electrode joint formed from first and second complementary elements, such as graphite electrodes, capable of being threadedly attached each other to form the board; where the threaded elements of the electrode joints have rounded aspects. The threaded elements are male projections having convex tips and multiple threads with rounded crests and valleys, or female receptacles having concave bases and threads, with ridges and rounded valleys. To further reduce the tension in the electrode joint, the end portions of the graphite electrodes may also have tapered ridges, between the threaded elements and the graphite electrode body. Optionally, one of the threaded elements may have at least one groove (and, preferably, a plurality of grooves) partially at least along its entire length; and additionally may include, a source of a flowable adhesive, in fluid communication with the groove. The source of adhesive capable of flowing can additionally comprise a flow-increasing material. Advantageously, the groove (and preferably a plurality of grooves) extends radially through the tip of the threaded element (and continues at least partially along its entire length). The source of adhesive capable of flowing can additionally comprise a flow-increasing material. The flowable adhesive advantageously comprises pitch, and is present as a plug disposed at the base of the female threaded element. Alternatively, one of the first and second complementary elements may have a shot containing adhesive formed therein, and in fluid communication with the slot. It should be understood that both the foregoing general description and the detailed description that follows further provide embodiments of the invention and are intended to provide a general view or framework of understanding of the nature and character of the claimed invention. The accompanying drawings are included to provide a better understanding of the invention, and are incorporated in the description and constitute a part of it. The drawings illustrate various embodiments of the invention and, together with the description, serve to describe the principles and operations of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial side view of a graphite electrode gasket of the prior art, including a first electrode having a threaded element and a second electrode having a female receptacle, inside which it can be receive the threaded element. Figure 2 is a partial sectional side view of a graphite electrode with a male protrusion having rounded aspects and tapered ridges, which is received within a female receptacle of a second graphite electrode. Figure 3 is a partial perspective side view of a graphite electrode with a male protrusion having rounded aspects and tapered protrusions, which is received within the female receptacle of a second electrode (shown in dotted) which also has rounded aspects and ridges tapering Figure 4 is a partial sectional side view of a fully tight male-female graphite electrode gasket, further including a plug of adhesive capable of flow, between the tip of the male protrusion and the base of the female receptacle. Figure 5 is a partial sectional side view of a non-tight graphite electrode gasket. Fig. 6 is a partial side view of a graphite electrode having a grooved male protrusion to receive an adhesive capable of flowing. Figure 7 is a partial side view, in section, of a graphite electrode having a slotted female receptacle, to receive an adhesive capable of flowing. Figure 8 is a partial side view of an electrode pin having rounded ridges and grooves to receive an adhesive capable of flowing. Figure 9 is a perspective view of a plug of adhesive material for optional placement on the base of the female receptacle, or on the tip of the male protrusion. Figure 10 is a partial side view of a graphite electrode having a grooved male protrusion, with drilling holes to receive an adhesive capable of flowing. Figure 11 is a partial sectional side view of a graphite electrode having a female receptacle with a piercing hole for receiving an adhesive capable of flowing. BEST MODE FOR CARRYING OUT THE INVENTION The graphite electrodes can be manufactured by first combining a fraction of particles comprising calcined coke, pitch and, optionally, mesophase pitch or PAN-based carbon fibers, in a master material mixture. More specifically, crushed, dimensioned, milled and calcined petroleum coke is mixed with a coal-tar pitch binder to form the mixture. The particle size of the calcined coke is selected according to the end use of the article, and is within the skill of the art. In general, particles up to about 25 millimeters (mm) in average diameter are used in the mixture. The particle fraction preferably includes a small particle size charge, which comprises coke powder. Other additives that may be incorporated in the small particle size charge include iron oxides to inhibit swelling (caused by the release of sulfur from its bond with the carbon, within the coke particles), coke dust and oils other lubricants to facilitate the extrusion of the mixture.

It is highly preferable that the carbon fibers (when used) are preferably present at a level of from about 0.5 to about 6 parts by weight of carbon fibers per 100 parts by weight of calcined coke, or about 0.4 percent to about 5.5 percent by weight of the total components of the mixture (excluding the binder). Preferred fibers have an average diameter of from about 6 to about 15 microns, and a length preferably from about 4 mm to about 25 mm and, most preferably, less than about 32 mm. The carbon fibers used in the process of the invention should preferably have a tensile strength of at least about 150,000 psi (1,033.50 MPa). Very advantageously carbon fibers are added a. the master material mix as you do; each bundle containing from about 2,000 to about 20,000 fibers. It is preferred to add the fibers after the mixing of the particle fraction and the pitch has begun. In fact, in a more preferred embodiment, the fibers are added after at least about half of the mixing cycle has been completed; very preferable, after at least about three quarters of the mixing cycle has been completed. For example, if the mixing of the particulate fraction and the pitch takes two hours (i.e., one mixing cycle is two hours), the fibers should be added after one hour, or even ninety minutes, of mixing. Adding the fibers after the mixing has started will help maintain the length of the fiber (which can be reduced during the mixing process) and, consequently, the beneficial effects of the inclusion of the fibers, which are believed to be directly related to the length of the fiber. As noted above, the particle fraction can include a small particle size charge (used here "small" in comparison to the particle size of the calcined coke, which usually has such a diameter, that a larger fraction of it passes through a 25 mm mesh screen, but not through a 0.25 mm mesh screen, and compared to conventionally used charges). More specifically, the small particle size charge comprises at least about 75 percent coke powder, by which is meant that it is coke having such a diameter, that at least about 70 percent, and more advantageously up to about 90 percent, it will pass through a 200 mesh Tyler sieve, equivalent to 74 microns. The small particle size charge may additionally comprise at least about 0.5 percent, and up to about 25 percent, of other additives, such as a swelling inhibitor, such as iron oxide. Again, the additive should be used at a smaller particle size than conventionally used. For example, when iron oxide is included, the average diameter of the iron oxide particles should be such that they are less than about 10 microns.

Another additive that can be used is petroleum coke, which has an average diameter of particles that is less than about 10 millimeters, added to fill the porosity of the article and, in that way, allow a better control of the amount of pitch binder used. The small particle size load must constitute at least about 30 percent, and up to about 50 percent, or even 65 percent of the particle fraction. After the mixture of the particle fraction, pitch binder, etc. is prepared. , the body is formed (or configured) by extrusion through a given die or molded into conventional forming molds, to form what is known as a green material. The formation, whether made by extrusion or by molding, is carried out at a temperature close to the softening point of the pitch, usually at about 1000 ° C or more. The die or mold can form the article into the substantially final shape and the substantially final size, although it is usually necessary to machine the finished article, at least to provide at least a structure such as the threads. The size of the green material may vary: for electrodes, the diameter may vary between approximately 220 mm and 750 mm. After extrusion, the green material is hot treated, baking at a temperature between about 700 ° C and about 1 100 ° C; more preferably, between about 800 ° C and about 1000 ° C, to carbonize the pitch binder to solid pitch coke, to give the article permanence, high mechanical strength, good thermal conductivity and comparatively low electrical resistance; and thus form the carbonized material. The green material is baked in the relative absence of air to prevent oxidation. Baking is carried out at a rate of elevation of about 1 ° C to about 5 ° C per hour, up to the final temperature. After baking, the carbonized material can be impregnated, one or more times, with coal tar or petroleum pitch or other types of resins or areas known in the industry, to deposit additional coke in any open pore of the material. Each impregnation goes followed then by an additional baking step. After baking, the carbonized material is graffitized. The grafitation is carried out by heat treatment at a final temperature of between about 2500 ° C and about 3400 ° C, for a time sufficient to cause the carbon atoms of the coke and the pitch coke binder to be transformed from the poorly ordered state to the crystal structure of graphite. Advantageously, the graffication is carried out by keeping the carbonized material at a temperature of at least about 2700 ° C and, more advantageously, at a temperature between about 2700 ° C and about 3200 ° C. At these high temperatures elements that are not carbon are volatilized and escape as vapors. The time required for maintenance at gipping temperature using the process of the present invention is not greater than about 18 hours; in reality, it is not greater than approximately 12 hours. It is preferred that the graffication be for about 1.5 to about 8 hours. Once the graphing is completed, the final item can be cut to size, and then machined or otherwise shaped to its final configuration. When the electrode joint is one that uses a pin, the pin is formed in a similar manner, although the number of pitch / bake impregnation steps may be greater for a pin, in order to give it greater strength. Once formed, the finished article is machined or otherwise shaped to its final configuration, to be used as a pin. When a male-female electrode joint is desired, the male protrusion (and, by extension, the female receptacle) must be advantageously sized so that the protrusion provides the required strength during use. More specifically, the ratio of the length of the male protrusion to the diameter, of the electrode (called the diameter, protrusion factor) of at least about 0.60, is convenient to create a male-female electrode joint having improved stability and commercially acceptable operation. In addition, a ratio of a factor defined by the ratio of the diameter of the male protrusion at its base to the length of the male protrusion (known as the factor of the protrusion diameter) should not be greater than 2.5 times the extrusion factor. for an especially effective joint with a protrusion factor of approximately 0.60. Actually, the protrusion diameter factor must vary, very preferably, with the protrusion factor, such that, when a joint with a protrusion factor greater than 0.60 is produced, the joint protrusion diameter factor must It is less than 2.5 times the cigarette butt factor. More specifically, for every 0.01 that is greater than 0.60 the extrusion factor of a joint, the maximum protrusion diameter factor should be approximately 0.016 smaller. Another feature of the joint that can come into play when designing an effective male-female joint is called the taper factor here, which is defined as the proportion of the taper (expressed in degrees) of the male protrusion with respect to the extrusion factor, which must be at least about 15, when the protrusion factor is 0.85, and must also vary when they occur together with different extrusion factors. For example, for every 0.01 that is less than 0.85 the extrusion factor of a joint, the minimum taper factor should be approximately 1 .25 greater.

Referring now to the drawings, the electrode joint according to the present invention is indicated by the reference number 10. Although the joint 10 is shown in the drawings in a specific orientation, it will be recognized that the joint 10 will assume a variety of orientations while in use. Additionally, for simplicity all the reference numbers are not provided in all the figures of the drawings. As illustrated in Figure 1, the prior art electrode gasket comprises a graphite electrode gasket 2, having a threaded element 4 (such as a pin) at the end portion of an electrode 8, and a receptacle 5 in the end portion of the adjacent electrode 9, such that the threaded element 4 can be threadably coupled with the female receptacle , to form the gasket 2. With reference now to Figures 2, 3, 6 and 7, the gasket design 10 of the invention also includes a first carbon element or body, such as the graphite electrode 11, and a second complementary element or carbon body, such as the graphite electrode 13, each of which has an end portion. The end portion of the first element 11 has a male protrusion 20, which comprises a curved or convex tip 22, and the end portion of the second element 13 has a female receptacle 30, which comprises a curved or concave base 32. The end portion of the first Element 11 may also have a threaded portion 24 extending from the convex tip 22, the threaded portion having several threads 26 with ridges 27 and valleys 29 rounded. Similarly, the end portion of the second element 13 may have a threaded portion 34, with several threads 36, each of which has rounded ridges 37 and valleys 39. Additionally, the end portions of the first and second elements 1 1 and 13, may also have complementary tapering ridges 28 and 38, extending outward from the threaded portion 24 of the male protrusion 20 of the element 1 1, and from the portion threaded 34 of the female receptacle 30, to the body 18 of the electrode 13, respectively. The most preferred embodiment of the electrode joint has a first element 1 1 having totally novel aspects: the convex tip 22, the rounded threads 26 and the tapered shoulder 28, and a second element 13 having completely novel aspects: concave receptacle 32, rounded threads 36 and tapered shoulder 38. However, alternative modes also include joints whose elements have only some partial combination of those aspects. For example, a joint with elements having only the convex tip 22 and the concave base 32, without the other aspects of the invention; joints whose elements have only tapered shoulders 28 and 38, and joints whose elements have only the aspect of the invention comprising the threads 26 and 38 with rounded ridges 27 and 37 and valleys 29 and 39 rounded, are novel and are covered by this invention. Of course, if the first element that constitutes a joint has a novel aspect, the second element that connects with the first element should have a complementary aspect, so that they can be joined effectively. Although the electrode joint is formed by causing the threaded portion 24 of the first element 11 to be received within the threaded receptacle portion 34 of the second element 18, it is not necessary that the tip 22 of the male boss 20 and the base 32 i of the female receptacle 30 are coupled. Rather it is said that the male boss 20 is received inside the female receptacle , even though the concave tip 22 is located only partially inside the base concavity 32. The male end portion of an electrode 11 is complemented by the female end portion of an electrode 13, so that they can be threaded to form a gasket 10. Although it is not necessary that any of the elements stop tightly with its complement to form a joint 10, in the preferred embodiment, the gasket 10 is formed when at least one aspect is coupled with its complement. The gasket design of the invention allows for different ways in which a gasket is formed: by bumping the shoulders 28 and 38, tightening the threads 26 and 36, or abutting the tip 22 and the base 32. As previously noted, and as illustrated in Figure 5, the convex tip 22 of the non-tightened male protrusion 20 may be formed with, or be received intimately within, the concave base 32 of the female receptacle 30. In this case, the convex shape of the tip 22 and the complementary concave shape of the base 32, serve not only to create a tighter fit of the protrusion 20 in the receptacle 30, than in the prior art, but also to distribute the tension across greater surface area, thereby a stronger joint is created. Similarly, as illustrated in Figure 4, the complementary end portions of the carbon members 11 and 13 can be formed in their threaded portions 24 and 34. The male protrusion 20 is received within the female receptacle 30 by screwing together the Complementary end portions, using rounded threads 26 and 36, until the threads are fully tightened or fully engaged. The rounded nature of the ridges 27 and 37 and of the valleys 29 and 39 of the threads 26 and 36, reinforces the joint by distributing the stresses over a larger surface area. Finally, when the protrusion 20 is not fully tightened, the joint 10 can be formed in the complementary shoulders 28 and 38, where the shoulders 28 and 38 bump so that the convex shoulder 28 snaps tightly into the concave shoulder 38. The taper of the shoulders reduce the tension of the joint by allowing the shoulders to connect more intimately, and by increasing the surface area through which the tension between the complementary aspects diffuses when they meet.

The novel aspects of the gasket design of the present invention are effective in reducing gasket stress and preventing cigarette butt loss, and can be used with graphite electrodes having male projections 20, as in Figures 2 and 3, or either using a pin 100, as illustrated in Figure 8. The pin 100 comprises opposite male elements 110a and 110b, each of which has a threaded portion 120a and 120b, respectively, and a rounded tip 122a and 122b, respectively . The shoulders 128a and 128b of the pin 100 may be tapered and the pin 100 may comprise threads 126 with ridges 127 and rounded valleys 129. As noted above, a flowable adhesive can be used to further improve the strength of the gasket 10, especially when the gasket 10 has a male boss 20 and a female receptacle 30 fully tightened, as illustrated in Figure 4 , so that each of the ridges 27 or valleys 29 of the threads 26 of the male protrusion 20, abutment with a ridge 27 or a valley 39 of the threads 36 of the female receptacle 30.

In order to use the flowable adhesive, the male protrusion 20 must be formed in such a manner that at least one groove or notch 24 extends at least partially along its entire length, as illustrated in Figure 6. In the preferred embodiment, a plurality of grooves 24 extends at least partially along the male protrusion 20; in fact, in the most preferred embodiment, four slots 24 are disposed along the male protrusion 20; each slot being disposed around the circumference of the male boss 20, at approximately 90 ° intervals (not shown). It is highly preferable that the slots 24 extend radially through the tip 22 of the male protrusion 20. A source of an adhesive material is disposed at the joint 10, at a location adjacent to the slot or slots 24. For example, A plug 40 of adhesive material, illustrated in Figure 9, may be placed on the base of the gasket 10, as shown in Figure 4, provided that the groove or grooves 24 extend completely to the tip 22 of the gasket. male boss 20; when the tip 22 of the male protrusion 20 approaches the base 32 of the female receptacle 30. The adhesive material 40 must be such that, under the conditions to which the gasket 10 is exposed, the adhesive material 40 flows to along the groove or grooves 24, and form an adhesive bond between the threads 26 of the male boss 20 and the threads 36 of the female receptacle 30, to work in that manner in order to prevent the seal 10 from being unscrewed. Advantageously the groove or grooves 24 do not extend fully in the shoulder 28, in order to prevent the flow of adhesive material out of the joint 10. In the case of a pin joint, the pin 100 may comprise grooves 124 for flow the adhesive capable of flowing. Suitable materials, useful as adhesive material, employed in the source 40, include cements and resins having melting temperatures lower than the temperature at which the gasket 10 is exposed in the furnace; but above the typical storage temperature of electrodes 11 and 13 (to prevent premature melting). Suitable cements or resins should be those that cure or coke at oven temperatures; so that, after they melt and flow around the threads 26 and 36, the materials are cured or coked to form the desired bond. Most preferably, the material comprises tar, which has a melting temperature lower than the temperature at which the gasket 10 is exposed in the furnace, but greater than the typical storage temperature of the electrodes 11 and 13; the pitch is also coked at the furnace temperatures, so that, after it melts and flows around the threads 26 and 36, co-exists to join the electrodes 11 and 13 of the joint together. The source 40 may comprise other elements in addition to the adhesive material itself. For example, a foaming agent, such as oxalic acid, may be included with the adhesive material together with metallurgical pitch and fine particles of carbon to facilitate the flow of the adhesive material along the groove or grooves 24. It may also be included , if desired, other materials, such as cements, binders, etc. Although the source of adhesive material in the form of a plug 1 provided in the base or gasket 10 can be provided, other locations for the source of the adhesive material 40 can also be contemplated. For example, as shown in Figure 10, one or more drilling holes or holes 46 can be formed in the male boss 20, so that the entrance to each drill hole 46 is in fluid communication with the slot or grooves 42; the hole or drilling holes 46 can have within them the source of adhesive material, so that, in the furnace, the adhesive material flows out of the hole or drilling holes 46, and along the slot or the holes. grooves 24. Similarly, the shots or hole or drill holes 48 can be formed in the female receptacle 30, as shown in Figure 1 1, provided that the inlets to the hole or drill holes 48 open towards the groove or grooves 24, are formed in the male protrusion. Thus, by using the gasket design of the present invention, the carbon bodies are more intimately bonded and the tension is distributed across a larger surface area, so that the stress of the gasket and the loss of butt be reduced beyond the level of the prior art. The descriptions of all the patents and publications cited, related to the present application, are incorporated herein by reference. The above description is intended to enable those skilled in the art to practice the invention. It is not intended to detail all possible variations and modifications that will become apparent to experienced workers, when they read the description. However, it is intended that all such modifications and variations be included within the scope of the invention which is defined by means of the claims that follow. The claims are intended to cover the elements and steps indicated in any arrangement or sequence, which are effective to meet the objectives intended by the invention, unless the context specifically indicates otherwise.

Claims (19)

1. CLAIMS 1 . A carbon body, comprising: a body having first and second end portions; Each end portion comprises a threaded element; at least one of the threaded elements comprises a male protrusion having a convex tip. The carbon body according to claim 1, wherein one of the threaded elements comprises a female receptacle 'having a concave base. The carbon body according to claim 1, wherein each of the threaded elements further includes a threaded portion comprising a plurality of threads having rounded ridges and valleys. 4. The carbon body in accordance with the claim 3, wherein each of the end portions further comprises a tapered shoulder extending outward from each of the threaded elements. The carbon body according to claim 1, wherein each of the first and second end portions further comprises a tapered shoulder extending outward from each of the threaded elements. The carbon body according to claim 1, wherein one of the threaded elements has a length partially along which at least one groove extends. The carbon body according to claim 6, wherein one of the threaded elements further comprises at least one shot containing adhesive; the at least one shot being in alignment with the slot. The carbon body according to claim 1, wherein the carbon body comprises a g-raphite electrode. 9. The carbon body according to claim 1, wherein the carbon body comprises a pin. 10. An electrode joint comprising: a. a first element having an end portion comprising a male protrusion with a convex tip; and b. a second element having an end portion comprising a female receptacle, with a concave base and which is threadedly attached to the male protrusion of the first element, so that the male protrusion is received within the female receptacle. eleven . The electrode joint according to claim 10, wherein the male protrusion further comprises a first threaded portion, close to the convex tip; the first threaded portion having a plurality of threads with rounded crests and valleys; and the female receptacle further comprises a second threaded portion, proximate to the concave base; the second threaded portion having a plurality of threads with rounded crests and valleys. 12. The electrode joint according to claim 10, wherein the end portions of the first and second elements further comprise tapered projections close to the first and second threaded portions. The electrode joint according to claim 12, wherein the male protrusion further comprises a first threaded portion, close to the convex tip; the first threaded portion having a plurality of threads with rounded crests and valleys; and the female receptacle further comprises a second threaded portion, proximate to the concave base; the second threaded portion having a plurality of threads with rounded crests and valleys. 14. The electrode joint according to claim 10, further comprising a source of adhesive capable of flowing, to reinforce the joint; the source being located between the male protrusion of the first element and the female receptacle of the second element. The electrode joint according to claim 10, wherein the first and second elements comprise graphite electrodes, and the joint comprises a male-female electrode joint. 16. The electrode gasket according to claim 10, comprising a source of flowable adhesive comprising a plug in the base of the female receptacle. 17. A method for forming electrodes, comprising: a. forming a first electrode having a body comprising an end portion with a tapered shoulder and a male protrusion; the male protrusion having a convex tip and a threaded portion with a plurality of threads having rounded crests and rods; and b. forming a second electrode having a body comprising an end portion with a tapered shoulder and a female receptacle; the female receptacle having a concave base and a threaded portion with a plurality of threads having rounded ridges and valleys, so that the electrodes can be threadedly connected with the convex tip of the male protrusion of the first electrode received in the concave base of the female receptacle of the second electrode. 18. The method according to claim 17, further comprising: forming at least one slot in the end portion of the first of the electrodes; the end portion having a length, partially along which runs at least one slot. The method according to claim 18, further comprising: forming at least one shot at the end portion of one of the electrodes, such that the at least one shot is in alignment with the slot; and inserting a source of adhesive capable of flowing, into the at least one shot.