WO1988000619A1

WO1988000619A1 - Line treatment unit for metal products

Info

Publication number: WO1988000619A1
Application number: PCT/FR1987/000284
Authority: WO
Inventors: Guy Gerard
Original assignee: Guy Gerard
Priority date: 1986-07-18
Filing date: 1987-07-17
Publication date: 1988-01-28
Also published as: EP0254633A1; AU7707487A; FR2601700A1; MA21037A1; FR2601700B1

Abstract

Unit for the treatment of band-shaped products (40), metal strip or wire, continuously thereby making it possible to carry out a plurality of types of treatment (heat treatment only (5)), galvanizing (9), painting (12) and their combinations or succession thereof comprising at least one heat equipment (5) the power of which is limited to a temperature increase of 750°C of a quantity of metal running continuously at a rate of 12 metres per minute.

Description

On-line processing unit for metal products

The present invention relates to an on-line processing unit for metal products, the design of which in sections, which can be made active independently, makes it possible to carry out several types of processing on the same line and to admit products with different characteristics as input. The putting into service of such or such section, its possible adjustment, the inhibition of other sections make it possible to condition the line for treatments such as a metallic coating of the product in the oven, than an organic coating of the paint type, that a succession of metallic and organic coatings, as heat treatment alone or prior to coating operations.

The architecture of the line and the different possible settings give the installation a plurality of functions which, usually, are carried out on separate machines, and consequently, by different manufacturers. In fact, metal coating equipment - galvanization for example - is heavy equipment, requiring a large investment whose profitability requires a large production and the most uniform possible. The main concern of the industrialist thus equipped is therefore completely contrary to that of the diversification of his production. It is the same for the production company of bands of metallic product painted or lacquered, or which carries out a heat treatment (blueing) on metallic flashing lights.

However, such mass productions impose constraints on the manufacturer both with regard to the quality of the products supplied as well as the outlets for the finished products, not allowing a production adapted to the more or less random and versatile needs of the market.

The present invention arose from the need in the steel industry, from a single production tool, to be able to manufacture different products of different qualities in the same range or of different natures, in order, on the one hand, to be able to absorb in basic product materials of various quality and nature therefore at competitive prices and, on the other hand, to be able to respond in a way more suited to the market and especially to variations in demand. 5 Having also noted that the most common operations for transforming a metal product into a strip, strip or wire, are a more or less complex combination of a limited number of elementary treatments which are: cleaning, surface preparation , a supply of calories, a coating by passing through a bath and cooling, a line having the means to ensure one or more times these elementary treatments on a product which runs continuously, should allow the manufacture of a large number of products according to the combination of treatments chosen from oven products which may be different from each other.

However, the classic designs of modern galvanization lead to more and more important lines to increase the production volume in order to improve profitability by lowering the cost price. This ever-increasing increase has come at the expense of the flexibility and adaptability of production lines. It is now common to encounter production lines, particularly in the field of galvanization, the production of which is between 30 and 50 tonnes / hour. The running speeds are then high, which leads to thermal equipment of considerable length in order to obtain a sufficient exchange of calories.

One of the first consequences of this gigantism is the inherent specialization of a line in the manufacture of a single product. Indeed, the slightest modification of the settings of a few parameters to obtain a slightly different finished product or to accept a product to be treated with different characteristics leads to either a line stop (with a considerable loss of productivity) , be there production of a large tonnage of scrap before the line has reached stabilized operating conditions. Furthermore, given the size of the installation, it is not possible to envisage the manufacture of a type of product under a low tonnage. This type of machine therefore imposes a high minimum threshold of the quantity of products to put in the oven, with the consequence of being forced to abandon smaller quantities of product for which there is a commercial outlet. For the same reasons, it is moreover hardly possible to conceive in these dimensions, a line comprising several treatment sections which can selectively be put into or out of service depending on the product placed in the oven and the product to be obtained. In fact, switching from one packaging of the line to another would result in a loss of productivity and or too much waste, as explained above. In addition, given the size of the equipment, the line's succession and location could only be fixed once and for all at the time of construction, leading to an installation through which the length of the product being treated becomes prohibitive and involves very significant power training means. Finally, it is commonly accepted, in the field of galvanization that below a running speed of the order of 20 to 25 meters per minute, there could not be a correct spinning of the molten zinc before solidification . The invention, on the other hand, constitutes an alternative to the conventional means of production, going against the technical and economic prejudices which have presided over the implementation of large installations.

Thus, the invention starts from the assumption that by greatly reducing the processing capacity of a line, the production cost is not necessarily increased. Indeed a reduced "flow" of treated product has many advantages. First of all, the total size of the unit is reduced, the length of product being treated requiring only drive power. completely acceptable. In addition, each section is also reduced in length, so that the equipment placed there is of such dimensions that, for at least some, it is possible to move them to dismantle or install them in another area of the path of the product, making it easy to change the line when you want to go from one treatment to another. This is particularly the case for thermal or cooling equipment. In addition, a shutdown of the unit only results in an absolute small drop in production, and the products in the oven can be of low tonnage. The unit can thus absorb basic products which it is impossible to process conventionally and which are available on the market at very low prices.

A i ns i, generally speaking, the unit according to the invention makes it possible to recover a large number of by-products or waste products from conventional treatment lines. It also makes it easy to adapt to various market demands while requiring only a much lower investment than that of conventional machines. A reduced flow necessarily imposes a low scrolling speed.

However, it has been found that it is entirely possible to properly spin a galvanized product below 15 meters per minute, contrary to the prejudice recalled above.

To this end, the subject of the invention is therefore an on-line processing unit for metallic products made of wires, strips or strips, adapted to produce on the product to be treated, depending on its nature, either a metallic coating or a coating. organic, either both successively, or a heat treatment alone or associated with the aforementioned coatings, comprising between a device for unwinding and continuously placing the product to be treated and a device for winding the finished product, in the direction of circulation of the product, at least one thermal calorie supply section, a metal coating section and a cooling section. According to one of the important characteristics of the invention, said calorie intake section comprises a base oven, the maximum heating power of which is defined by its ability to heat from ambient temperature to approximately 750 ° C., an amount of metal at most equal to 7 tonnes per hour continuously passing through said furnace, at a constant speed at most equal to 12 meters per minute and means for adjusting the power of this furnace between this maximum value and zero and for fixing the atmosphere of the last.

Compliance with these limits allows the design of a completely different generation of galvanization lines that are much cheaper and much better suited to a market that is very diverse in demand. In order to be able to adjust the operation of the unit as well as possible, in particular according to the thickness of the products to be treated. the unit according to the invention may furthermore comprise, upstream of the above-mentioned oven, a preheating oven, the maximum power of which is defined by an increase in the temperature of the product passing through it under the above-mentioned maximum speed, of about 250 ° vs.

In known manner, means will have been provided to make the metal coating section inactive with respect to the product to be treated. It will be advantageous to provide said unit, downstream of the metal coating section, with an organic coating section comprising means to make it inactive with respect to the product to be treated.

In a preferred architecture of the invention, the unit comprises means for guiding the product between the two coating sections, defining a first vertical upward circulation zone of the product leaving the metal coating section, then a first area of high horizontal circulation, then a vertical downward circulation zone of the product up to the entrance to the organic coating section.

In addition, the unit comprises, at the outlet of the organic coating section, a second vertical rising circulation zone of the product, followed by a second horizontal zone substantially at the level of the above-mentioned first horizontal zone. These zones are intended to receive means for complementary treatment of the product essentially of a thermal type (supply or extraction of calories) which will be put into or out of service depending on the products to be treated or the products to be obtained and which may or may not be removable. .

Furthermore, the unit according to the invention comprises means for making one or other of the coating sections constituted by elements deviating the path of the product inactive with respect to the product, allowing, for example, to avoid the galvanizing bath, pass the product directly from the oven outlet into the first rising circulation zone and, to avoid the paint zone (organic coating), go directly from the first to the second horizontal zone.

Finally, at the outlet of the unwinding device, the unit includes a rinsing cleaning section which may or may not be used depending on the nature of the products in the oven, as well as a surface treatment section in particular for the organic coating. .

The invention will be better understood during the description given below by way of purely indicative and nonlimiting example which will make it possible to identify the advantages and the secondary characteristics thereof. Reference will be made to the appended drawings in which:

FIG. 1 is a schematic view of a unit according to the invention,

- Figures 2 to 6 schematically illustrate some of the different possible uses of the unit.

Referring first to FIG. 1, it can be seen that the unit of the invention comprises, between a device 1 for unwinding the product to be treated (metal strip, strip tape or wire) and a winding device 2 of the treated product: a) a cleaning section 3 comprising one or more tanks

3a for chemical degreasing and rinsing of the product, associated with deflector rollers 3b so that the product circulates continuously in this or these tanks, b) a chemical preparation and treatment section 4 (for example a phosphating treatment) known in itself- even ; c) a thermal section 5 for supplying calories composed of a main oven 5a having airlock devices and supplying an atmosphere suitable for the heat treatment to be carried out. This oven will be pre ference constituted by a refractory tunnel, flame or electric resistance whose power will be limited to obtaining a temperature at the outlet of the oven of the order of 750 ° C for a product passing through it at constant speed at most equal at 12 meters / minute. In 5b there is shown diagrammatically an additional oven, preferably an induction oven which can be disposed upstream of the oven 5a in a removable manner to carry out preheating (for large strip thicknesses) or to constitute a means of adjusting the temperature rise curve. of the product. The power of this furnace will be limited to allow a 250 ° C rise in the "flow" of the above metal. The advantage of this limit lies in the fact that the oven remains of a reasonable size allowing it to be manipulated and moved in a simple manner, in particular to place it in another zone for circulation of the product along the line where an intake of calories would be necessary (lacquering or "galvanealing"); d) a thermal regulation section 6 disposed at the outlet of the oven 5a, which can also be placed under an atmosphere, so, depending on the desired treatment or the product in the oven, either to promote temperature uniformity or to create cooling for lower this temperature to that of a metal coating bath. Section 6 has two outputs, one όa in the direction of a deflection roller 7, the other 6b in the direction of a bath 8 of metal coating (alloy based on molten zinc). The outlet 6b is extended to the bath by a chute 6c for protection and confinement of the atmosphere; e) a metal coating section 9 which comprises the bath 8 in a tank 8a surmounted by a device of a wringing device disposed in whole or in part in a confined atmosphere in order to avoid in particular the problems which the 'coating oxidation; f) a first zone 10 for the upward circulation of the product from the metal coating section 9 followed by a first high horizontal zone 11 at the outlet from which the product can be cut or continue horizontally. 10a and 11a show thermal type equipment for heat exchange (supply or extraction of calories), the nature and function of which will be more precisely specified with reference to the following figures. This equipment can be arranged in these areas in a fixed or removable manner; g) an organic coating section 12 comprising a paint tank 12a, the coating being carried out for example by dipping; h) a second rising circulation zone 13 of the product at the outlet of the section 12 followed by a second horizontal zone 14 each of which is provided with equipment of the thermal type 13a and 14a removable or not.

In t re these zones esetsecti on s, and inside some of them if necessary, there are tables or rolls for supporting the product circulating in the unit, moreover, the unit includes return rollers such as 3b and 7 as well as those 15 and 16 making it possible to bypass the path of the product if necessary to short-circuit sections of the unit whose implementation is not required for the treatment considered (see the examples in the following figures ). Some of these rollers (roller 7 for example) can be retracted in order to release, or not to impede the passage of the product along another route.

In this regard, it should be noted that each section can be made active or inactive with regard to the product, independently. For sections such as 3, 9 and 12 where a physical contribution is made to the product, making them inactive consists in short-circuiting them by modifying the path of the product.

For the other sections in which it is essentially a heat exchange (possibly with a metal-gas chemical reaction), their passivation with respect to the product consists simply in not putting them into operation or putting them partially into service . So the thermal section 5 can operate either in an atmosphere or open (in the open air), -as well as the thermal equipment in zone 10-, or operate only at reduced temperature, in particular for drying the product which has undergone previously the action of several surface treatment baths.

In Figure 2 there is shown the implementation of the unit according to the invention to perform the bluing (heat treatment) of a product 20 (one or more metal ribbons obtained by slitting strip) of work hardened steel. the elements already described. have the same references, but only those active in relation to the product are referenced. It can therefore be seen in this figure that only the sections 3.5 are in service, the product being diverted from the galvanizing tank by the roller 7 and diverted from the organic coating section. The oven and its atmosphere will have been adjusted in this application (which may be air) at a temperature of the order of 450 550 ° C. It will be noted that the oven 5a has at its output means for brutally cooling the product which, implemented at their maximum efficiency, make it possible to lower its temperature to around 90 ° C. The equipment 10a will then consist of an additional cooler.

In FIG. 3 it is the metallic coating of a product 30 which is represented, the active sections being here also only referenced.

When the product loaded is a work hardened steel, the thermal section 5 is under an appropriate atmosphere, adjusted to obtain a product temperature of the order of 700 to 750 ° C., if necessary using preheating, by the oven 5a. , which is then brought by the cooling section 6, also under a protective atmosphere, to a temperature close to that of the bath (400 to 450 ° C. if this bath is a zinc alloy) of section 9. This section is completely or partially under atmosphere, preferably neutral, to avoid oxidation of the coating. The equipment 10a is put into service to cool the coated strip to a temperature allowing complete solidification of the coating, so that the product can be wound up without damage on the roll 17. In zone 11, the equipment 11a will be an additional cooler.

In the case where the product to be treated is hot-rolled pickled steel or cold-rolled annealed steel, the oven 5 is adjusted to bring the product between 600 and 650 ° C. The commissioning of the induction furnace is then no longer necessary except in the case where it is desired to increase the thickness of the strip under the same running speed. The other sections and equipment are set to roughly the same values as those described above. One can imagine that the equipment 10a is a furnace and in particular the furnace 5b which, disassembled from its preheating zone, is reassembled in the zone 10 ,, allows both to transform the metallic deposit into an alloy with the base metal. In that case,. the subsequent cooling of the product will be carried out by the equipment 11a and 14a.

FIG. 4 illustrates the conditioning of the unit for galvanization followed by an organic coating of the product 40. It will be noted that with the exception of section 4, all the sections and equipment are activated. The adjustment of the galvanization will take place as indicated above, depending on the nature of the product in the oven, while the strip, at the outlet of the additional cooler 11a is diverted by the roller 16 to the section 12 to then be dried by equipment 13a (a baking oven) and be cooled by the cooling device 14a. The equipment 13a may advantageously be constituted by the induction furnace 5b if the implementation of preheating is not necessary.

FIG. 5 shows the unit according to the invention, configured to paint a product 50 which must be degreased in 3, and / or treated on the surface in the chemical treatment station 4, dry in the oven 5 at reduced temperature and in air before introducing it into the organic coating section 12.

The organic coating equipment and the associated thermal equipment can be replaced, in the unit according to the invention, by chemical treatment or electroplating equipment to carry out the final coating of the product or the chemical transformation of the last thickness of its surface layer.

The invention finds an interesting application in the field of the treatment of metallurgical products in strip or wire sheet.

Claims

1. On-line processing unit for metallic products (20, 30, 40, 50) in wires, strips or strip, adapted to produce on the product to be treated according to its nature, either a metallic coating or an organic coating, either both successively, or a heat treatment alone or associated with the aforementioned coatings comprising between an unwinding device (1) and continuous feeding of the product to be treated and a winding device (2) of the finished product, in the direction of circulation of the product at least one thermal section (5) for supplying calories, a section (9) of metallic coating comprising means (7) to make it inactive with regard to the product to be treated, and a section (10a) of cooling, characterized in that said heat supply section (5) comprises a base oven (5a), the maximum heating power of which is defined by its ability to heat from ambient temperature to approximately 750 ° C. number of metal at most equal to 7 tonnes / hour continuously passing through said furnace, at a constant speed of passage at most equal to 12 meters per minute and means for adjusting the power of this furnace below its maximum power and for fixing the atmosphere of the latter.

2. Unit according to claim 1 characterized in that it comprises upstream of the above-mentioned oven (5a) a preheating oven (5b) whose maximum power is defined by an increase in the temperature of the product passing through it under the aforementioned maximum speed about 250 ° C.

3. Unit according to claim 1 or claim 2 characterized in that downstream of the section (9) of metallic coating an organic coating section (12) comprising means (16) to make it inactive to the with regard to the product to be treated.

4. Unit according to claim 3 characterized in that it comprises means for guiding the product between the two sections (9,12) of coating defining a first zone (10) for vertical circulation of the product at the outlet of the metal coating section (9), then a first zone (11) for high horizontal circulation then a vertical circulation zone for the product down to the entrance of the section organic coating (12).

5. Unit according to claim 4 characterized in that it comprises at the outlet of the section (12) of organic coating a second zone (13) of vertical upward circulation of the product followed by a second horizontal zone (14) substantially at the level of the above-mentioned horizontal high zone (11).

6. Unit according to claim 5 characterized in that the first zone (10) of said montan vertical circulation is equipped with a cooling device (10a) while the second said horizontal zone also includes a cooling device (11a).

7. Unit according to claim 6 characterized in that the above-mentioned first horizontal zone (11) comprises means for removably receiving either a cooling device or a device for supplying calories

8. Unit according to claim 5 characterized in that the second zone (13) of upward circulation of the product comprises means for removably receiving a calorie supply device (13a).

9. Unit according to claim 4 characterized in that the means for rendering the above-mentioned coating sections (9,12) inactive consist of means (7,16) for deviating the path of the product arranged between the base oven (5a ) and the first upward circulation zone (10) and between the above-mentioned first (11) and second horizontal zones (14).

10, Unit according to any one of the preceding claims, characterized in that it comprises at the outlet of the unwinding device (1) a degreasing section rinsing (3) of the product and means (3b, 15) for guiding the product to lead or avoid it.

11. Unit according to any one of the preceding claims, characterized in that it includes, upstream of the preheating section (5b), a surface treatment section (4).

12. Unit according to any one of the preceding claims, characterized in that it comprises, at the outlet of the base oven (5a) an atmosphere confinement zone (6) extending up to the metal coating section (9) and constituting the product temperature regulator.