MXPA97009593A - Coating and curing in line of a soldier pipe in continuous motion, with a polimero organ - Google Patents

Abstract

A pipe product and an improvement in the production of coated pipe, as is most preferred, includes a galvanized hot-dip galvanized pipe coating, and prior to complete solidification of the zinc coating, controlled cooling and coating transparent of the pipe with an organic polymer coating. The heat of the galvanizing process cures the transparent coating, and the clear coating retains the consistency and reflectivity of the zinc that is not previously seen in the finished products. In the further preferred embodiments, organic polymer coatings are applied to the zinc-coated and uncoated pipe, and the organic polymer coatings are applied by an electrostatic powder coating process.

Description

COATING AND CURING IN LINE OF A SOLDIER PIPE IN CONTINUOUS MOVEMENT. WITH AN ORGANIC POLYMER BACKGROUND OF THE INVENTION This invention relates to the on-line coating of a continuously moving substrate, such as a pipe, pipe, or conduit, of the type used for applications such as metal fences, fire protection pipe, pipe or pipe. mechanical, or electrical conduit. More specifically, this invention relates to the galvanization and coating of these substrates. The technique of forming, welding, and coating tubes and pipes is an old technique. There are many manufacturing operations that use decades-old techniques. As an example, modern galvanization procedures have been described, such as the anachronistic inheritance of the original hot dip galvanization, where the cold items were submerged in heated zinc containers. See United States of America Patent Number 4,352,838, in column 1, lines 13-19. Although the technique is old, industrial leaders have made significant advances. These advances include the advance of the PCT Publication No. WO 93/00453 published on January 7, 1993, in advance of the United States Patent Number 5,364,661 issued November 15, 1994, and the progress of the Application of US Pat. No. 08/287856 filed August 9, 1994. As reflected in these patents and publication, the galvanization of continuous tubes and ducts has progressed to the point of rapid velocities of the tubes and ducts that are they will galvanize, of the order of 182.88 meters per minute. Galvanization has also progressed through the elimination of secondary containers or elevated zinc in favor of zinc pumped through cross-shaped tees, spray nozzles, and drip nozzles. The residence times in the application of zinc has been reduced to tens of seconds, and the contact zones to centimeters. Industry leaders have also advanced in the application of non-metallic coatings, as shown in United States Patent Application Number 08 / 243,583 filed May 16, 1994. As in this patent, they apply protective coatings by a vacuum coating apparatus. Coatings applications have also been made known through alternative coating technologies. As shown in U.S. Patent Nos. 3,559,280 issued February 2, 1971, 3,616,983 issued November 2, 1971, 4,344,381 issued August 17, 1982, and 5,279,863 issued January 18, 1994, Electrostatic coating has been considered as a possibility. As disclosed in U.S. Patent No. 3,559,280, electrostatic spray coating is performed after water spraying, sizing, straightening, and drying, and in the multiple steps and places of a spraying or coating section, a separate baking or hardening chamber next, a following separate air fan, and a subsequent separate water sprayer. As disclosed in U.S. Patent No. 3,616,983, the electrostatic powder coating is made as an alternative to other coating methods after the first application of liquid coatings, and after heating is applied by a external heater. As disclosed in U.S. Patent No. 4,344,381, the electrostatic spray coating is made in an inert atmosphere, with liquid coating materials based on organic solvents.

Patents of the United States of North America Numbers 3,122,114; 3,226,817; 3,230,615; 3,256,592; 3,259,148; 3,559,280; 3,561,096; 4,344,381; 4,582,718; 4,749,125; 5,035,364; 5,086,973; 5,165,601; 5,279,863 and 5,364,661 and the Publication of the TCP number WO 93/00453, are incorporated by reference.

SUMMARY OF THE INVENTION Despite the advances of the technique, an opportunity for invention has remained in the application of coatings to zinc-coated and uncoated tubing. The times and distances for the coatings to be applied and cured, have created at least in part barriers to the increases in the speeds in the production in continuous line of pipe. Over-spray, runoff, and the like, have caused a substantially incomplete use of the coating materials, and a waste. The coatings have been inconsistent in thickness and covering, and thicker than necessary. In summary, therefore, the invention is both pipe products and improvements in the production methods of coated pipe continue. As further preferred, the pipeline and improved production, include galvanized hot-dip galvanized pipe coating, and immediately after the solidification of the surface of the zinc coating has occurred, in-line, the transparent coating of the pipe with an organic polymeric coating. The remaining latent heat of the galvanization cures or thermofrages the clearcoat, and the clearcoat retains a consistency and brightness, or reflectivity, of the zinc, which had not previously been seen in the finished products of continuous zinc pipe coating, in the chrome range. In the additional modalities, organic polymeric coatings are applied to zinc-coated and uncoated tubing, and the organic polymeric coatings are applied by electrostatic powder application. The dust is not charged when it comes out of its nozzles, and it is loaded into the fields created by an array of charged wire grids. The powder is thermofraged to coat the pipe in about 5 seconds, and the coating is finished without liquid coating materials, afterburning, or any baking or hardening chamber. The full scope of the invention, and its objects, aspects, and advantages will be understood by a complete reading of this specification in all its parts, without restricting one part to the other.

BRIEF DESCRIPTION OF THE DRAWING The preferred embodiment of the invention will now be described with reference to the accompanying drawing. The drawing consists of four figures, as follows: Figure 1 is a perspective view of the practice equipment of the preferred embodiment of the invention in a tube production mill. Figure 2 is a second perspective of the apparatus of the preferred embodiment, that is, a coater, separated in parts, to reveal the internal detail. Figure 3 is a diagram of the powder feeding apparatus of the preferred embodiment. Figure 4 is a flowchart of the placement of the coating apparatus as is most preferred in the tube mill.

DETAILED DESCRIPTION OF THE PRESENT INVENTION A preferred embodiment of the invention is practiced in a process and with equipment as shown in Figure 1. Pipe 10, previously formed from steel strip, and previously welded is moved in and through of a coater 12 in the direction of the arrow 11. The auxiliary equipment of the coater 10 is mounted on a movable frame 14. The powder for coating the pipe 10 moves from a fluidized bed 16 through the bores 18, 20, towards the nozzles not shown in Figure 1, and diffuses to the coater 12. The powder coats the previously heated pipe 10, which leaves the coater 12 in the direction of arrow 22. Referring to Figure 2, the coater 12 houses an array 24 of charged electrical wires that establish a field or electrostatic fields around the pipe 10 that passes through the coater 12. The nozzles not shown in Figure 1 are the nozzles 26, 28 in Figure 2, and as shown in Figure 2, the nozzles 26, 28 diffuse the powder to the arrangement 24. The pipe 10 is grounded, and the powder, loaded by the arrangement 24, moves through the electrostatic fields of the array, to be attracted to, and to settle on, the pipe 10. To any degree that it does not settle on the pipe, the powder is removed from the coater 12, and recovered to be reused. Referring again to Figure 2, the pipe 10 is preferably pipe formed from continuous metal strip moved through a series of pipe-forming rolls, to bring the side edges of the strip together, and form the strip in a circular cross section. When the lateral edges are adjacent to one another, they are welded, in line, as is known from past practices. With or without additional operations, the pipeline proceeds to the coater 12 in the formed and welded pipe condition. From the place of removal of the supply rolls, to the place where the pipe is cut into sections, the strip forming the pipe, and the resulting pipe, proceed in a continuous line along a single continuous central axis. Accordingly, the axis of the pipe defines a longitudinal direction along the direction of movement of the pipe, and transverse axes perpendicular to the longitudinal axis. In addition, the direction of movement is towards the "downstream" or the "front", and the direction opposite to the direction of movement is "upstream" or "backward". The whole process forms a production mill or a tube mill. The housing 30 of the coater, as shown, takes the form of a substantially rectangular box, with its largest dimension, ie its length, of a few meters, in the longitudinal direction. By modifying the rec angularity, the upper part 32 is inclined inward towards the axis of the pipe 10 in the upstream direction. The inclination of the upper part helps to direct the non-applied powder towards an extractor, not shown, in the rear bottom of the coater 12. As shown, the arrangement 24 includes four grids 34, 36, 38, 40 of wire segments, such as segment 42. Currently four grids are preferred, separated by approximately 15.24 centimeters to 17.78 centimeters, although other numbers of grids and separation distances are considered acceptable. Each grid extends in a transverse plane, and each grid is a hexagon of wire segments centered on the axis of pipe 10. Hexagons are also currently preferred, although circles and other shapes are considered acceptable. The hexagons appear to provide the best symmetry for the pipe of a circular cross section. The grids 34, 36, 38, 40 are electrically isolated from the surrounding support structure, not shown, by insulators, such as the insulator 44, and the grids are loaded to approximately 50 volts with a milliampere current for a tube of any diameter, and for a minimum distance of the tube to the grid from 7.62 to 10.16 or less centimeters. For the larger diameter round pipe, or the pipe with a geometric cross section, the grids are reconfigured to maintain a distance of 7.62 centimeters to 10.16 centimeters between the grid and the pipe. The pipe is grounded, as above, and the potential difference between the grids 34, 36, 38, 40 and the pipe 10, charges the powder entering the array.

The powder is discharged when it leaves the nozzles 26, 28, and initially enters the arrangement, and arrives to charge at the entrance. As a corollary, the nozzles 26, 28 are not charged either. The advantages of the initially uncharged powder and the uncharged nozzles are the reduction of the tendency of the dust to form fabrics from the grids to the nozzles, and the independence of the powder diffusion function of the nozzles and the electrostatic function of the nozzles. rack. The four grids 34, 36, 38, 40 each form an electrostatic field centered on the planes in which they remain, and consequently, the dust diffused through the grids undergoes up to four electrostatic fields. The separation of the grids is understood to make the electric fields of the grids essentially independent of each other, and that independence is considered preferable. Referring again to Figure 1, the powder is initially placed in bulk in the fluidized bed 16. As is typical of fluidized beds, the bed 16 contains a membrane, with powder on top, and a gas chamber below. The powder in the fluidized bed 16 is forced from the fluidized bed under pressure, to the double augers 18, 20. The auger 18 feeds the lower nozzle 28; the auger 20 feeds the upper nozzle 26. The gas chamber of the bed 16. The gas chamber of the bed 16 receives a supply of nitrogen, which is inert and dry, passes through the membrane, conditioning the powder up against the compaction . An erect tube per auger, starts in the fluidized bed above the membrane, and extends down through the bed to a powder storage area of the auger. A level sensor in the auger's dust storage chamber responds to the dust level in the auger's dust storage chamber, to drive a cone valve in the erect tube, to allow dust to enter the auger. Erect tube, and in this way fall into the auger. Each auger is from AccuRate Bulk Solids Metering, a division of Cari Schenck AG, and each auger includes a screw or auger through which powder is transported from the auger to the coater 12. Although augers are currently preferred, the auger feeders type described in U.S. Patent No. 5,314,090 is considered an acceptable alternative. Referring to Figure 3, the powder falls from the augers, such as auger 18, through a thinned passage 46 in a connector block 47, into a constricted passage 48, which is supplied with nitrogen at its elbow 50. The fall from the auger to the elbow 50 is under the action of gravity, and is pulled by a venturi effect; the powder moves from the elbow 50 to the nozzles, such as 28, under nitrogen pressure. The additional nitrogen supplied in the nozzle through the inlets 52, 54 helps to project the powder from the outlet of the nozzle 29. As shown in Figure 2, the nozzles 26, 28 are directed and project the powder in the direction longitudinal of the pipe. The nozzles also direct and project the powder in the upstream direction. In this way, the nozzles cause the powder to form an axial cloud around the pipeline as the dust comes out of the nozzles. Although two nozzles are currently preferred, above and below the pipe, two nozzles on each side, and three and more nozzles in alternative configurations are considered acceptable. In addition, the nozzles can direct the powder downstream from the back of the coater 12. The powder used in the preferred embodiment of the invention is a thermosetting polyester. More specifically, the powder is a thermoformable triglycidyl isocyanurate polyester (TGIC), essentially resin with trace amounts of accelerators. The powder is a crosslinking polyester, as opposed to air-dried or non-crosslinked polyester, and is quick curing. Preferably, the powder is cured or thermoformed in 5 seconds or less at 204 ° C-315 ° C, with the melt occurring at approximately 135 ° C. The powder can be transparent or pigmented. More preferably, the powder is clear polyester X23-92-1 from Lilly Powder Coatings, Lilly Industries, Inc., Kansas City, Missouri. The triglycidyl isocyanurate polyester is preferred because of the impermeable nature of its crosslinked barrier coating, the maintenance of its mechanical and physical properties in a thickness range from about 2.54 microns to about 76.2 microns, its resistance to scratching, its resistance to corrosion, and its resistance to chemical degradation of methyl ethyl ketone, alcohols, caustic solutions, and light acids. The speed of the pipe as it moves through the coater 12, the speed of application of the powder, and the thickness of the coating applied on the coater, are related to one another. As shown and described, the coater 12 can give a coating of 25.4 microns thick, with a "line speed" of 152.4 meters per minute, and alternatively, a coating of 12.7 microns thick at 304.8 meters per minute. For combinations of higher thicknesses and higher speeds, a second coater, such as a backing with the former, may be appropriate. A pipe with an external diameter of 3,175 centimeters, has a surface area of 0.0999 square meters per linear meter and with a line speed of 152.4 meters per minute, the speed of application of the coater, defined as the grams of powder used per minute in the coater, is approximately 467.2 grams per minute, or 461.3 grams per minute. With a pipe with an external diameter of 3,835 centimeters, and a surface area of 0.1206 square meters per linear meter, and a line speed of 152.4 meters per minute, the speed of application is 33.85 kilograms per hour, or 557.25 grams per hour. minute. A lower density powder requires a lower speed; a higher density powder requires a higher speed. With a coater 12 as shown and described, a coating can be applied to the pipe at any desired location between the passages by which the pipe is formed. The preferred coating material requires a temperature of 204 ° C to 315 ° C to cure, and sufficient space along the line to cure in five seconds. The heat for this coating process can be supplied as in the past coating processes, through a preheating of the pipe by induction heaters, or by the latent heat of the galvanization process. When starting, the tube mills as contemplated, often pass discontinuities of tube formed and incompletely welded down the line. The open slot that must be otherwise closed by welding, often sprays steam, water, or the internal coating. The liquids and vapors from this slot are detrimental to the coater 12. Referring to Figure 1, in the preferred coater, a shield 52 is placed in the line, and the pipe passes through the shield 52 to protect the coater. While the coater 12 is operating, and the welded pipe is being coated on the coater 12, the shield 52 is in the illustrated retracted position, outside the coater 12. However, with any interruption of the mill or line, the shield 52 it can move longitudinally along the pipe between the nozzles 26, 28, to an advanced position inside the coater 12 to protect the interior of the coater 12 from any pipe spray section. The shield 52 can move between the advanced and retracted positions under the action of a chain pulse 54. The pulse 54 moves a cam connected to a link of the chain in an oval movement around an oval track 55. The cam extends in a transverse groove of a cam follower (not shown). The cam follower is restricted to longitudinal linear movement along a pair of parallel protective tubes 60, 62, by virtue of including a tube follower (not shown) adapted on the tubes 60, 62 to slide along the tubes. Accordingly, whenever it is necessary to protect the interior of the coater 12 against discontinuities in the pipe, the shield 52 can be easily moved upstream to the coater 12, and whenever appropriate, to release the shield 52 from the coater 12, it is it can move from the protector 52 downstream outward of the coater 12. Although the coater 12 described can be placed at any desired location in the equipment by which the pipe is formed, welded, and coated, consistently with the needs of its placement as it is described, and although the heat can be supplied for curing by induction and other heating units, a specific placement of the coater 12, and a specific source of curing heat is particularly desired. Referring to Figure 4, coater 12 is more preferably placed downstream of a zinc coating bath or other zinc coating or galvanizing apparatus 64. As in the past and in more current processes, zinc is applied to the Pipe in this apparatus through a zinc bath, pumping through any of the different zinc application devices. Also, as in these apparatuses and processes, an air knife or a cleaner can adjust the thickness of the zinc coating applied in the apparatus. In the pipe forming process, a controlled cooling sprayer 66 follows the galvanizing step. The sprayer directs water into the pipe, and lowers the temperature of the pipe exterior to a scale of about 204 ° C to 315 ° C. Zinc in a galvanizing step is typically maintained from 454 ° C to 482 ° C, and to promote the formation of the alloy between the zinc and the substrate by transferring heat to the pipe, the pipe entering the galvanizing step and the apparatus, is typically heated to the temperature of the zinc. In some cases, zinc can reach 593 ° C through the heat supplied by the pipe. The temperature drop made by the controlled sprayer and the quenching, is a temperature drop on the pipe surface from 121 ° C to 315 ° C or more, again up to a scale of 204 ° C to 315 ° C. The temperature and the amount of water used in the sprayer 66, depend on the line speed of the pipe, the temperature of the galvanization step, the diameter of the pipe, the thickness of the pipe wall, and the like. In test runs, water sprayed from a 27-nozzle arrangement spaced circumferentially and longitudinally around the pipe, required approximately 3.7854 liters per minute in total water at room temperature water. The adjustment of the amount of water used in the sprayer 66 for a specific line can be done by the person of ordinary experience in this field, in the exercise of that ordinary experience. The pipe that comes out of the galvanization step of the production, has a chrome-like appearance, consistent, and highly reflective, before solidification. In contrast, the galvanized pipe that comes out of the production of the complete pipe has the conventional mottled and opaque appearance of the galvanized materials. Therefore, the appearance in the form of chromium of the pipe that leaves the step of galvanization in the past, has been an ephemeral phenomenon or highly transient and unstable. It is understood that the mottled and opaque appearance of conventionally galvanized materials is the result of the action of the water that extinguishes the materials, and that in the past, there have been no techniques or psses that have varied in a significant or consistent manner. mottled or opaque zinc coatings. In contrast to the quenching of the past, the controlled cooling sprayer 66"captures" or temporarily maintains the chrome-like appearance of the pipe as it exits the galvanizing step. Accordingly, the controlled sprayer 66 captures the surface appearance by controlled surface cooling in order to lower the melting point of the zinc, and still maintains the latent heat in the piping leaving the sprayer 66. As used in this description, "latent heat" means, unless otherwise defined in the context, the heat retained in the pipe primarily as a result of the pssing steps that incidentally heat the pipe, and exclude the heat caused in a primary or complete manner by the heating applied through heaters. As a consequence, and when the piping of the controlled sprayer 66 comes out, and immediately enters the coater 12, as desired, the pipe retains the latent heat of the electroplating pss which is correct to perform the melting and curing of the powder coating applied in the coater. The placement of the steps of the pss and the equipment as described, results in the freedom of the requirement of a secondary heating applied to perform the coating on the coater 12. Substantial energy savings are realized.

As is implicit, the coater 12 and the sprayer 66 are associated in their position in the tube mill, in such a way that the transparent coating applied in the coater 12 is immediately on the galvanizing coating of the pipe, as it is applied in the galvanization step. "Immediately on", with reference to the coatings, means, unless otherwise defined in the context, that the outer coating is applied on and in contact with the galvanized coating described, without an interposed coating or other material. The consequence of the sequence of the steps of the pipe production shown and described is that the transparent coating of the coater 12"captures" and improves the chromium appearance of the galvanized coating of the pipe in a permanent manner. When the pipe is turned off, as in step 70, immediately after coating 68, the shutdown occurs in contact with the transparent coating, and not in contact with the galvanized coating, and in this way, the galvanized coating is not speckled or opaque. The galvanizing coating is additionally sealed by the transparent coating against oxidation. Again, the consequence is that the zinc coating is visible through the transparent coating, and retains the brightness more of the chromium than of the cooled zinc, and improves and distinguishes the resulting pipe from the processes described, as a matter of class, and does not of degree. Furthermore, the consequence of the sequence of steps as shown and described is that the coating with triglycidyl isocyanurate polyester of the coater 12, is thermoformed or cured without the addition or inclusion of a baking or hardening chamber immediately. of the coater 12. The coating is cured in transit to the next steps of tube formation, such as the quenching of the galvanizing heat after coating, which essentially have nothing to do with the coating process or apparatus. The pipeline resulting from the processes described, and as invented, is in the form of chromium, galvanized, is coated with transparent polyester, is highly resistant to contact damage, has superior resistance to corrosion, chemical degradation, and otherwise It is highly desirable. The preferred embodiments and the invention have now been described in a complete, clear, concise, and accurate language to enable a person of ordinary skill in the field to make and use the invention. Variations in the preferred embodiment are possible, which are within the scope of the invention. As an example, as reported, the coating material may be transparent or pigmented, although emphasis is placed on the transparent coating. In addition, the heat to cure the coating can be applied to tubing at room temperature, or to partially heated tubing, by induction or other heaters, or by the latent heat of other processes. As with the processes of the past, the preferred embodiments and the invention can be used with pipe, pipe, and conduit, of the types used for applications such as metal fences, fire protection pipe, mechanical pipe or pipe, electrical conduit, and other applications. As a consequence of the many variations possible with the invention, the following claims conclude this specification to particularly point out and claim in a distinctive manner the subject matter considered as the invention.

Claims (26)

NOVELTY OF THE INVENTION Having described the above invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. In a tube product (10) of the type comprising a metal base tube with or without a zinc coating, and with an overlay of organic polymer, the improvement comprising that this organic polymer is a non-solvent based polymer applied immediately on the metal base tube (10).

2. The improved tube product (10) according to claim 1, characterized in that the tube product (10) is formed by applying the non-solvent based organic polymer coating to the metal base tube (10). ) in the form of a powder.

3. The improved tube product (10) according to claim 2, characterized in that the tube product (10) is formed by spraying the non-solvent-based organic polymer as a powder in the metal base tube. (10) during the travel of the tube (10).

4. The improved tube product (10) according to claim 1, characterized in that a galvanized zinc coating is applied to the metal base tube (10), and the non-solvent based organic polymer is applied immediately on galvanized zinc coating.

5. The improved tube product (10) according to claim 1, claim 2, claim 3, or claim 4, characterized in that the non-solvent-based organic polymer is transparent.

6. The improved tube product (10) according to claim 5, characterized in that the galvanized zinc coating, as observed through the non-solvent based organic polymer coating, has a reflectivity in the scale that It is provided by chromium.

7. The improved tube product (10) according to claim 1, characterized in that the metal base tube (10) is formed from a metal strip, and where the tube (10) is heated to achieve a sufficient latent heat to thermofragment the organic polymeric coating, and wherein the tube product (10) with the coating, is cut into separate tube products.

8. The improved tube product (10) according to claim 1, characterized in that the metal base tube (10) is formed from a metal strip, where the molten zinc forms a galvanized coating hot dip on the outer surface of the metal base tube (10), wherein the hot-dip galvanized coating is cooled to a temperature lower than that necessary to achieve a latent heat sufficient to thermofragment the organic polymeric coating, wherein the The pipe (10) is reheated to achieve sufficient heat applied to thermofragment the organic polymeric coating, where the organic polymeric coating is subsequently applied to the pipe (10), and the pipe (10) is cut into individual pipe products.

9. The improved tube product (10) according to claim 1, characterized in that the metal base pipe (10) is formed of a metal strip, where a hot dip galvanized coating is formed on the outer surface of the metal base tube (10), wherein the hot-dip galvanized coating is cooled to achieve a latent heat sufficient to thermofragment the organic polymeric coating, wherein the organic polymeric coating is immediately applied over the galvanized coating. hot dip, and where the tube (10) is cut into individual tube products.

10. The improved tube product (10) according to claim 1, characterized in that the tube product (10) is formed from a metal strip, wherein the metal base pipe has a hot-dip galvanized coating on the external surface, wherein the hot-dip galvanized coating is cooled to ambient conditions, where the metal pipe (10) is heated to a temperature for thermofragmenting the organic polymeric coating, wherein the organic polymeric coating is applied immediately to the hot-dip galvanized coating, and wherein the tube (10) is cut into tube products.

11. The improved tube product (10) according to claim 7, claim 8, claim 9, or claim 10, characterized in that the organic polymer coating is applied in the form of a powder .

12. The improved tube product (10) according to claim 7, claim 8, claim 9, and claim 10, characterized in that the product of metal tube (10) has the polymer organic applied electrostatically in the form of a powder.

13. In a tube product (10) of the type having a metal base tube (10) with a zinc coating on the metal base tube, the improvement comprising a coating of a non-solvent based organic polymer, transparent , applied immediately on the zinc coating, the tube product (10) having a reflectivity on the scale that is provided by the chromium.

14. The improved tube product (10) according to claim 13, characterized in that the organic polymeric coating has been applied to the tube in the form of a powder.

15. The improved tube product (10) according to claim 1, claim 2, claim 3, wherein the organic polymer is pigmented.

16. The improved tube product (10) according to claim 1, characterized in that the organic polymer is a thermosetting crosslinking polyester.

17. The improved tube product (10) according to claim 1, characterized in that the non-solvent based polymer coating is in the range of 2.54 microns to 76.2 microns in thickness.

18. The improved tube product (10) according to claim 1, characterized in that the non-solvent-based organic polymer coating is scratch resistant and corrosion resistant.

19. In a process of the type wherein the production of coated products having a metal base includes the step of continuously forming a tube (10) from a strip of metal, an improved process comprising the step of applying a coating in non-solvent-based organic polymer powder, thermoformable, immediately on the pipe (10), in a continuous direct line.

The improved process according to claim 19, characterized in that the production includes, after the step of continuously forming the metal strip in a pipe, and before the step of applying an organic polymeric coating, the step of advancing continuously piping formed through molten zinc, to form a hot-dip galvanized coating on the outer surfaces of the formed metal pipe (10).

21. The improved process according to claim 19 or claim 20, characterized in that the organic polymer coating is transparent.

22. The improved process according to claim 19, characterized in that it includes the step of applying the organic polymeric coating immediately on the galvanized zinc coating after a controlled cooling of the galvanized zinc coating, to achieve a sufficient latent heat. for thermofragmenting the organic polymeric coating, the thermofixing being carried out by the latent heat.

23. The improved process according to claim 19, characterized in that it includes the step of applying the organic polymer coating on the galvanized zinc coating, after cooling to ambient conditions, and the step of reheating to reach the thermofixed of the organic polymer coating, the thermofixing being carried out by the heat of the superheat.

24. The improved process according to claim 19, characterized in that it includes the step of applying the organic polymeric coating in an electrostatic manner.

25. The improved process according to claim 20, characterized in that the organic polymeric coating is transparent, and which includes the step of applying the organic polymeric coating immediately on the galvanized zinc coating, and wherein the galvanized zinc coating , visible through the organic polymeric coating, has a reflectivity on the scale that is provided by the chromium.

26. The improved process according to claim 23, characterized in that it includes the step of applying the organic polymeric coating on the galvanized zinc coating, then a controlled cooling of the galvanized zinc coating, to achieve a sufficient latent heat to thermofragment the organic polymeric coating, the thermofixing being carried out by the latent heat.