GB2146669A - Card clothing - Google Patents

Abstract

There is disclosed a method of making card clothing which comprises a foundation, and an array of card wire teeth carried by the foundation, in which the method comprises: subjecting a coated steel card wire to a hardening and tempering treatment to render the card wire suitable for use in card clothing; and setting the treated card wire into the foundation into an array of toothed card wires; in which the coating on the steel card wire is a metallic coating which provides corrosion-resistance to the treated card wire when water is present, and which has a sufficiently high melting point that the coating does not undergo any appreciable deterioration during the subsequent hardening and tempering treatment.

Description

SPECIFICATION Card clothing This invention relates to card clothing which is particularly intended for use in the textile industry.

Card clothing is used in the textile industry as an external cladding which is applied to the working surface of cards (carding cylinders) and doffers, and also with raising and brushing apparatus used to finish certain types of cloth. Card clothing is also used more widely in association with apparatus outside the textile industry, for brushing, cleaning conveying and tensioning purposes.

Card clothing comprises a fillet of material formed from a woven foundation and which forms a carrier for a densely packed array of wire teeth. Card clothing applied to a card is used in the initial treatment of staple fibers, such as wool and cotton, and also synthetic fibers, to form slivers for subsequent formation into yarns.

It has been the practice for many years to make card clothing with "bright" steel wire. The wire is drawn-down from wire stock to a desired card wire diameter, is rolled to shape if required and is then hardened and tempered. The card wire is then inserted in a succession of separate U-formed strips into the woven foundation by high speed setting machinery to provide a densely packed array of wire teeth with profiles to suit the particular intended use e.g. a woollen card or a worsted card.

This provides card clothing economically, and which is generally acceptable for many operators. However, bearing in mind that the carding of wool fibers is often accompanied by the presence of a high proportion of moisture, this can lead to deterioration in the wire structure on card clothing over a period of time. Thus, bright wire will deteriorate in the presence of moisture by rusting or other corrosion, with an adverse effect on the operating performance of the card clothing causing wire breakage. Moisture can be present owing to (a) the location of a card in a region of high humidity (which is often the case in textile industries in the Third World), (b) the storage of the staple fibers in damp conditions prior to processing and (c) moisture present in the staple fibers, whether intentional or unintentional.In regard to the presence of moisture in the staple fibers, there is little incentive to a supplier to remove such moisture since traditionally staple fibers are sold by weight.

With a view to overcoming the adverse effects of moisture on bright steel wire, card clothing has been made with coated steel wire, the coating being resistant to corrosion in the presence of moisture. Tin, cadmium and zinc are the main coating materials used in the card clothing industry to give card wire protection against corrosion. However, all of such coatings are applied to card wire after the card wire has been hardened and tempered.

The coatings are applied to already hardened and tempered card wire by a "hot dip', method which comprises passing a strand of wire through a succession of liquid baths which will usually be an acid bath, water wash bath, a flux bath and then a bath of the molten metal coating material. The wire has to be wiped clean after treatment in each bath, and the process inevitably provides many opportunities for faulty handling giving rise to risk of bending or crooking the wire under dipping bars and wipers, thereby rendering the wire unsuitable for card clothing manufacture.

As in any in-line process, there is wastage through starting and finishing ends and, in addition, many yards of wire have to be discarded in attempts to find suitable tangle-free running ends. Waste usually amounts to approximately 18% of raw wire material.

Although tin and cadmium provide an acceptable finish to card wire, both of these metals are becoming increasingly expensive. Also, cadmium hot-dip coating has been, or is becoming outlawed from use in many countries owing to the inevitable generation of extremely hazardous fumes. Zinc has the advantage that it is much cheaper, but it provides a coating which has a dull matt type of finish which most end users consider to be undesirable.

There are also problems in providing satisfactory anti-corrosive coatings associated with the hot dipping process. Hot-dipped wire is often "lumpy" due to inefficient wipping after dipping and this can cause breakdowns in the card wire setting machines which are equipped to drive very small diameter card wire into the cloth foundation and are therefore particularly susceptible to malfunction when improperly sized wire is presented thereto.

In the case of tin coatings, the colour of the coating can often vary, and this causes an unsatisfactory striped effect on the finisihed card clothing. If the wire is not cleaned properly prior to dipping, it can be badly plated and the coating will flake-off and patches may be missed during inspection and prior to further treatment.

In view of the numerous potential faults in the application of hot-dip coatings of tin, cadmium and zinc to card wire, the manufacturer of card clothing has to anticipate greater raw material wastage and production loss than with uncoated bright steel card wre.

It will, of course, also be appreciated that tin, cadmium or zinc coatings cannot be applied to card wire prior to the hardening and tempering treatment of the wire, since this treatment would inevitably cause deterioration and loss of the coating material which has too low a melting point to endure such treatment without adverse effect.

Accordingly, there has developed a need to provide a treatment for card wire which will permit economic application of a satisfactory coating to the wire which will resist deterioration in service when exposed to moisture.

According to the invention there is provided a method of making card clothing which comprises a foundation, and an array of card wire teeth carried by the foundation, the method comprising the steps of: subjecting a coated steel card wire to a hardening and tempering treatment to render the card wire suitable for use in card clothing; and setting the treated card wire into the foundation into an array of toothed card wires: in which the coating on the steel card wire is a metallic coating which provides corrosionresistance to the treated card wire when water is present and which has a sufficiently high melting point that the coating does not undergo any appreciable deterioration during the subsequent hardening and tempering treatment.

The above process has the advantage of avoiding the necessity to apply coatings by a hot dip process subsequent to the hardening and tempering treatment with all of the disadvantages of the known processes referred to above.

By adopting a method according to the invention, it is possible to provide coated toothed card wires having: a) a more even coating b) a smoother finish c) consistent colour d) reduced waste e) greatly reduced cost.

It is preferred that the coated steel card wire is derived from steel wire stock which is precoated prior to drawing-down of the wire stock to a desired wire diameter. The pre-coating may be by any convenient means, preferably by electroplating.

One particularly suitable coating material is brass (Cu 65%-75% and Zn 25%-35%), and the brass coated wire stock may be of the type supplied by National Standard company as hose wire (which is used in hose reinforcement).

Other advantageous metallic coating material comprises bronze or nickel which, along with brass, have high melting points (above 1 200"C).

After the pre-coated steel wire stock has been drawn-down to a desired card wire diameter, the wire is then subjected to a hardening and tempering treatment. However, in the case of shaped wires, any necessary shaping is carried out on the drawn-down card wire, prior to the hardening and tempering treatment.

During hardening, the card wire is heated to above the transformation temperature (725"C-1 100"C), which changes the crystalline structure of the core metal of the wire (carbon steel) to what is known as the austenitic form. The wire is then quenched or cooled quickly to below 200"C, causing the austenitic structure to decompose into the martensitic (brittle) form.

The wire is then tempered by heating it up to below the critical temperature, approximately 200 to 500"C, in order to relieve the stresses and to allow an arrested reaction of cementite to take place by letting the wire cool on its own accord.

During the hardening and tempering treatment of the card wire, no appreciable deterioration shoud occur with the material of the external metallic coating. However, card wire coated with metal or alloys with high melting points (above 1 200 C) such as bronze, brass or nickel, may undergo some slight surface deterioration during the hardening and tempering treatment, by discolouring or oxidation, unless measures are taken to carry out the treatment as far as possible in the absence of oxygen. Accordingly, in order to achieve the high quality performance and appearance required by the card maker, the hardening and tempering treatment may be carried out using muffle tube furnaces (electric or gas).Depending upon the type of alloy or metal used in the coating, controlled atmospheres may be required in the furnace tubes in order to retain the original consistent colour and bright finish of the coating.

In the case of brass coated card wire, the end product is not only substantially cheaper than hot dipped tin plated card wire, but has equal if not better anti-corrosive properites than any of the hot dipped coated card wire currently available.

Card clothing made by a method according to the invention may be used in the textile industries in the carding process. It may also be used to finish certain types of clothes in such applications as raising and brushing. The card clothing may also be used outside the textile industry, in any situation in which brushing, cleaning, conveying or tensioning is required.

The invention is also concerned with card clothing formed by a method in accordance with the invention.

Accordingly, in a further aspect of the invention there is provided card clothing comprising a foundation, and an array of card wire teeth carried by the foundation, the card wire teeth having been formed from a steel card wire which has been subjected to a hardening and tempering treatment to render the card wire suitable for use in card clothing, and which has then been set into the foundation into an array of toothed card wires: in which the steel card wire has an external metallic coating aplied thereto prior to the hardening and tempering treatment, the coating being made of metal or a metal alloy which provides corrosion-resistance to the treated card wire when water is present and which has a sufficiently high melting point as not to undergo any appreciable deterioration during the hardening and tempering treatment.

It is preferred that the coating on the steel card wire is brass, bronze or nickel.

One example of the invention will now be described with reference to the accompanying schematic drawing.

Referring now to the drawing, there is shown a flow diagram of the process steps involved in forming card clothing having a woven foundation strip, and an array of toothed card wire carried by the strip. A supply of carbon steel wire stock is provided to a card wire specification. The wire stock is coated, by electro plating, with an anti-corrosive metal or alloy coating. The coated steel wire stock is then drawn-down to the required card wire diameter. There-after, with optional rolling to shape in the case of shaped wires, the drawn-down card wire is subjected to conventional hardening and tempering treatment to a card wire specification.

The hardening and tempering treatment takes place on the already coated steel card wire, and the coating is of such a type as not to undergo any appreciable deterioration during the hardening and tempering treatment. Thereafter, the hardened and tempered card wire is supplied to a setting machine which sets the card wires in separate U-shaped strips into a card cloth. The setting machine is well known in the manufacture of card clothing. The card cloth also may be of conventional construction, comprising a woven foundation web, preferably with a rubber coating, which is then cut longitudinally into a plurality of separate strips (fillets) which carry the array of toothed card wire. Any of the well known arrays of toothed card wire may be provided at the required density to suit the requirements of a particular card operator.

After setting, any of conventional further procceses may be applied, if required, and then the finished card clothing is obtained for application to further equipment according to requirements. The card clothing may be applied to woollen or worsted cards, or in finishing apparatus for cloth e.g. for nap raising, felting or brushing. The card clothing may also be used in, suede cleaning brushes, velvet press boards, hand cards and drum carding, dog brushes and animal grooming brushes, file cards with or without hands, cleaning cards.

However, it is envisaged that the card clothing described herein will be particular suitable for use with woollen cards.

The carbon steel wire used to provide the steel wire stock is preferably supplied already coated with the anti-corrosive coating. A particularly suitable starting material comprises brass coated wire at a diameter of 0.304 mm (0.012 inches) which is currently supplied as reinforcing wire for hoses. This comprises brass plated carbon steel wire, and the steel wire core is derived from steel rod with carbon in the range 0.6 to 0.7%. The following specifications of the carbon steel wire are suitable: 1). Carbon 0.55-0.60 ; Manganese 0.50-0.70% Silicon 0.30% max. ; Phosphorous 0.03% max.

Sulphur 0.03% max. ; Nickel 0.01% max.

Chromium 0.1% max. ; Copper 0.1% max.

Molybdenum0.05% max. ; Tin 0.05% max.

Aluminium 0.005% max.; Total residual and trace elements 0.3% max.

2). Carbon 0.63-0.68%; Manganese 0.50-0.70%; Silicon 0.30% max. ; Phosphorous 0.04% max.; Sulphur 0.04% max. ; Nickel 0.15% max.; Chromium 0.15% max.

Copper 0.20% max. ; Total residual and trace elements 0.40% max.

3). Carbon 0.67-0.72%; Manganese 0.50-0.70% Silicon 0.30% max. ; Phosphorous 0.03% max.

Sulphur 0.03% max Nickel 0.01% max. ; Chromium 0.01% max Copper 0.1% max.; MolybdenumO.05% max. ; Tin 0.05% max.

Aluminium =.005% max.

Total residual and trace elements 0.30% max.

Brass is a particularly suitable coating material, which is an alloy of copper 65 to 75% and zinc 25 to 35%. The coating is applied in a proportion of 4 to 10 grams per kilogram of core steel wire.

The specification of hose wire obtainable from National Standard company of Kidderminster are particularly suitable for use in the formation of toothed card wire, though other coated steelwire may be used. In place of brass, bronze or nickel coated wire may be used, which also have a sufficiently high melting point as to resist any serious deterioration during the hardening and tempering treatment which is applied to the card wire subsequent to the application of the coating.

As described above, the foundation for the array of toothed card wire is a woven foundation strip. However, it should be understood that the invention is applicable with any of the other conventionally available forms of foundation made of, for example, leather, laminated cloth etc.

The coating applied to the card wire, prior to the hardening and tempering treatment, provides improved corrosion resistance to the card wire when water is present. However, it is envisaged that end users will also consider the coating to provide improved carding of the fibers as compared with conventional card wire made of bright steel wire.

Claims (14)

1. A method of making card clothing which comprises a foundation, and an array of card wire teeth carried by the foundation, the method comprising the steps of: subjecting a coated steel card wire to a hardening and tempering treatment to render the card wire suitable for use in card clothing; and setting the treated card wire into the foundation into an array of toothed card wires: in which the coating on the steel card wire is a metallic coating which provides corrosionresistance to the treated card wire when water is present and which has a sufficiently high melting point that the coating does not undergo any appreciable deterioration during the subsequent hardening and tempering treatment.

2. A method according to claim 1, in which the coated steel card wire is derived from steel wire stock which is pre-coated prior to drawing-down of the wire stock to a desired wire diameter.

3. A method according to claim 2, in which the pre-coating is carried out by electroplating.

4. A method according to any one of the preceding claims, in which the coating is a brass coating.

5. A method according to claim 4, in which the brass has a constitution of 65 to 75% Cu and 35 to 25% Zn.

6. A method according to any one of claims 1 to 3, in which the coating is a bronze or nickel coating.

7. A method according to claim 2 or 3, in which the drawn-down wire stock is subjected to a hardening and tempering treatment.

8. A method according to claim 7, in which the card wires are shaped wires, and any necessary shaping is carried out on the drawn-down card wire prior to the hardening and tempering treatment.

9. A method according to any one of the preceding claims, in which the hardening is carried out by heating the card wire to above the transformation temperature which changes the crystalline structure of the core metal of the wire to austenitic form, rapidly cooling the wire to below 200"C, causing the austenitic structure to decompose into the martensitic form, and in which the tempering is carried out by heating the wire up to below the critical temperature, approximately 200 to 500"C, in order to relieve the stresses and to allow an arrested reaction of cementite to take place by letting the wire cool on its own accord.

10. A method according to claim 9, in which the hardening and tempering treatment is carried out using muffle tube furnaces.

11. A method according to claim 10, in which controlled atmospheres are used in the furnace tubes, depending upon the type of alloy or metal used in the coating, in order substantially to retain the original consistent colour and bright finish of the coating.

1 2. A method according to claim 1 and substantially as hereinbefore described.

1 3. Card clothing when made by a method according to any one of the preceding claims.

14. Card clothing comprising a foundation, and an array of card wire teeth carried by the foundation, the card wire teeth having been formed from a steel card wire which has been subjected to a hardening and tempering treatment to render the card wire suitable for use in card clothing, and which has then been set into the foundation into an array of toothed card wires: in which the steel card wire has an external metallic coating applied thereto prior to the hardening and tempering treatment, the coating being made of metal or a metal alloy which provides corrosion-resistance to the treated card wire when water is present and which has a sufficiently high melting point as not to undergo any appreciable deterioration during the hardening and tempering treatment.

1 5. Card clothing according to claim 14, in which the coating on the steel card wire is a coating of brass, bronze or nickel.