JPH057117B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in the method of cladding a steel core rod with another metal, comprising:
This makes it difficult for harmful oxides to form.

DESCRIPTION OF THE PRIOR ART For various reasons, it is known to combine the advantageous properties of the core material with the surface properties of the cladding material by cladding a metal rod with another metal, and it has been found to be possible to achieve better results by cladding a metal rod with another metal. Economic advantages result from the limited use of expensive cladding materials. Reference may be made thereto to US Pat. Nos. 3,714,701, 4,227,061 and 4,331,283. In known devices, one or two metal cladding pieces made of copper material, for example, are
It has been proposed to use two or more rods, heat them, and then solid state weld them around a heated steel core rod member.

In order to obtain a uniform clad product with predetermined dimensions,
Clad products are often reduced in diameter by drawing operations.

One of the problems in continuous cladding processes, especially for medium and high carbon steel core materials, is that the cooling rate must be slowed to prevent hardening of the steel core, resulting in a reject level on the surface of the cladding material. One example is the formation of oxides. In order to obtain a clean rod surface, it is known to carry out a subsequent chemical cleaning, for example pickling, or to mechanically remove the oxidized layer on the surface. Furthermore, it is also known to provide an inert atmosphere or a reducing atmosphere throughout the slow cooling zone. but,
These auxiliary equipment are a considerable burden.

The inventors have previously shown that after lowering the temperature to an appropriate temperature by air cooling, the clad rod is passed through a reducing atmosphere chamber containing, for example, decomposed ammonia, to restore the already formed oxide layer to its original metallic state. I have suggested that you give it back. A significant problem in this case is that, as a direct result of the gaseous reduction process, the reduced metal layer is porous and physically unstable. This layer tends to separate during the subsequent drawing or deforming process, and very harmful flakes or dust are formed on the surface, interfering with subsequent processing and use of the clad product.

Although it has long been known to cool steel products in boiling water to prevent the formation of needle-like transformation products by providing a moderate cooling rate, the present invention It is not yet known to cool clad steel products in boiling water to achieve this purpose. A common example is water literature. Tendler, “Rod Cooling Control,” Wire Journal, February 1981, pp. 84-91; “Hardening of Rail Steel by Quenching in Boiling Water,” Industrial Heating, March 1981, pp. 8-10; Economopoulos et al., “EDC "Processes, Metaradical Background and Industrial Applications", Wire Journal,
March 1981, pp. 90-95.

Therefore, the next treatment does not require a cooling chamber that introduces a special atmosphere or subsequent chemical or physical cleaning operations, and there is no metal loss due to oxidation or the formation of oxides. This is why there is a real need for a method to continuously produce clean clad steel products without the formation of metal sponges that must be removed in post-processing.

(Summary of the Invention) The present invention solves the above problems.

After joining the clad material to the steel rod,
Clad products are quenched by immersion in hot water at or slightly below the next boiling point. This cooled product is then immersed in a second, cooler cooling medium (water). The first quench is carried out to between about 160 and 212, preferably between about 195 and 205, depending on the carbon content of the steel core to be treated. Preferably, the cooling action is carried out at atmospheric pressure.

This treatment is particularly effective when medium or high carbon steel rods are used as the core material.

The object of the present invention is to identify an improved method of reducing the formation of undesirable oxides on the surface of clad steel products.

The present invention makes it difficult for oxides to form on the surface of the clad product and eliminates the need for a chemical oxide removal process such as pickling or a physical oxide removal process before proceeding to the next process such as drawing. Another purpose is to clarify a cladding method that does not

The invention further aims to define a device that can be used economically and effectively.

The present invention forms a shiny clad surface,
A further aim is to avoid the formation of a surface layer on the metal sponge due to reduction.

The invention further aims to define a method which does not require air cooling means or alternatively cooling means enclosed in an inert or reducing atmosphere.

These and other objects of the invention will be more fully understood from the following description of the invention based on the embodiments shown in the drawings.

(Description of preferred embodiments) “Medium carbon steel” as used herein refers to approximately 0.16 to
It shall mean a steel containing 0.30% carbon; "high carbon steel" shall mean a steel containing more than about 0.3% carbon.

The method of handling individual cladding pieces and core rods does not form part of the present invention in the same way as these solid-state bonding methods, but appropriate means may be provided upstream of the cooling device unique to the present invention. do it. Therefore, for convenience of explanation, only a means of performing cladding will be described here. Specific means are disclosed in US Pat. No. 4,227,061.

FIG. 1 shows the final product, in which one or more cladding pieces 2, 4 are joined to the core 6.

In the embodiment shown in FIG. 2, a rod-shaped steel core 10 passes through a cleaning station 12 to clean the outer surface of the rod. Conveniently, the rod is supplied from a reel of material (not shown);
It is carried from the direction of the arrow. Rod is joining roll 1
4, 16 to solid state bond the metal cladding pieces 18, 20, and each roll has a
A groove is formed to receive a portion of the cladding piece and core assembly. Cladding pieces 18, 20
The cladding pieces 18, 20 which have been cleaned, or which have already been cleaned as part of this process, pass through tension rolls 24, 26, respectively, and then through electrically energized electrical contact shoes 34, 35. pass through each. The shoe heats the cladding pieces 18,20 by means of a resistor energized by a power supply 36 and wires 30,32. Power supply 36 is further connected to bonding rolls 14, 16 through wire 38 to form the low potential end of the circuit.

Core rod 10 is also preheated. This heating is accomplished using an electrical induction coil 40 wrapped around a non-conductive tube 42. The end cap 44 is provided with a cylindrical inlet 45,
A gas that suppresses oxidation of the rod is supplied to the pipe 4 through the inlet.
It will be introduced in 2. Chamber 46 is under positive pressure, rod 10 and cladding pieces 18, 20 are housed in the chamber, and reducing gas is introduced to prevent oxidation of the rod and cladding pieces before joining.

In a preferred embodiment of the invention, steel core 10 is made from medium carbon steel or high carbon steel. Among some desirable cladding materials:
These metals are not sensitive to the cooling rate of the heated water used here, and at temperatures ranging from room temperature to the boiling point of water, surface oxidation does not occur even when exposed to water or a solution containing a suitable buffer. doesn't happen.
For example, something like monel. Preferred cladding materials include materials selected from the group consisting of copper, copper alloys, nickel, and nickel alloys.

After bonding, the clad product 50 exits the bonding apparatus and passes through a transfer chamber 51 containing an inert gas or a reducing gas such as decomposed ammonia. The composite material, preferably moving at a speed of about 45 to 60 feet per minute, first passes through an overflow tank 52 containing water 54 at about the same temperature as the water 58 in the first cooling tank 56. The decomposed ammonia enters the tank 52 from the transfer chamber 51 and occupies the top of the water 54 . Clad product 50 is thus protected from corrosive or oxidizing atmospheres by both water 54 and ammonia. tank 56
The temperature of the water 58 is between about 160°C and the boiling point.
In the case of pure water, the boiling point is 212〓 at 1 atmosphere.
The water temperature is preferably in the range of 195〓 to 205〓. When the composite article 50 exits the bonding equipment, it is at a temperature in the range of approximately 1650° to 1800° or higher. Rapid cooling with heated water is performed in the first cooling tank 5.
The water temperature and maintenance time are determined so that the steel core is lower than 1100〓 in 6. The cooled composite rod 50 is then passed to a second overflow tank 66 containing water and a headspace filled with a gas such as nitrogen. The rods 50 are delivered to a second cooling tank 72 containing water 74 at a lower temperature than the water 58, preferably below about 80°C or around room temperature.

Tanks 52, 56, 66, 72, and 76 are generally rectangular in shape and made of a suitable material, such as stainless steel or coated steel. tank 5
2, 56, 64, 66 are generally sealed with their tops closed, but tanks 72, 76 may be open or closed.

This ensures that the clad steel core is not exposed to as much of a corrosive or oxidizing environment as it exits the bonding rolls 14, 16 and exits the second cooling tank 72. In the illustrated embodiment,
This creates a protective gas environment within the chamber 51, maintains the clad article 50 in an atmosphere of protective gas, and/or tanks 52, 56, 66, 72.
This is achieved by maintaining a water level of

Openings are provided in the walls of the tanks 52, 56, 66, and 72 to allow the cladding rod 50 to pass therethrough. Seal means may be provided if necessary. Water 58 leaving the tank 56 is received upstream in an overflow tank 52. This water is designated at 54. The second overflow tank 66 is separated by a wall 67, with the upstream side receiving hot water 68 from tank 56 and the downstream side receiving cold water 69 from tank 72. Water 54 is supplied by pipes 60, 71, 64 and pump 62.
from tank 52 and water 68 from tank 66 can be returned to tank 56.

The tank 72 is separated from the overflow tank 66 by a wall, and the water leaving the tank 72 enters the overflow tank 66 as water 69 and can be taken out through the drain 70. Furthermore, a portion of the water 74 is transferred to the third overflow tank 7 as water 78.
6 and can be discharged through drain 79.

A suitable make-up water source (not shown) and heating means (not shown), such as immersion heaters, steam heaters, heat exchangers, etc., may also be provided for starting and adjusting operations. The water 58 can also be maintained at a predetermined temperature using the heat retained by the cladding.

If necessary, the clad product 50 may be passed through a skiving process (not shown) to
Excess cladding material protruding from the outside, such as fins, can also be trimmed.
The cooled rod is then taken up on the take-up reel 8.
It is wound to 0. The composite material can be drawn directly from the cooling station, or it can be rewound onto reels 80 for storage and/or transportation for further processing. Retention time of any part of the clad rod in the tank 56 (passage speed as described above)
is within the range of about 15 seconds to 50 seconds, preferably about 25 seconds to 45 seconds.

(Examples) In order to further deepen the understanding of the essence of the present invention, examples are shown below.

The cladding apparatus may be of any suitable type, including suitable preheating means and bonding rolls, for bonding the rod and one or more cladding pieces. The core member consists of a C1060 steel core rod approximately 0.344 inches in diameter, and the two cladding pieces each have a width dimension of approximately one-half the circumference of the steel rod. Clad pieces are 0.625 inches wide and approximately 0.032 inches thick.
Made from CDA102 copper. Steel core rods are heated to approximately 1800℃ by high frequency induction heating, and steel clad rods are heated to approximately 1200℃ by resistance heating.
It is heated to 〓. The temperature of the clad product coming out of the bonding roll is approximately 1700℃. The diameter of the cladding rod is approximately 91% of the sum of the rod diameters and the thickness of the two original cladding pieces is reduced by passing through the joining rolls.

Cladrods move forward at a speed of about 55 feet per minute. The first cooling tank is filled with water and has a width of about 8
It measures approximately 6 inches deep and 30 feet long. Water at a temperature of approximately 200°C is stored here. The time that each part of the clay rod is maintained in heated water is about 33 seconds, and the first
It passes through a water-cooled tank and comes out at a temperature of about 950°C to 1000°C. It is preferable that the clay rods are sent to the next water-cooled tank. The tank measures approximately 8 inches wide by 6 inches deep by 8 feet long and contains room temperature water. Clad products have a clean appearance with virtually no buildup of harmful oxides on the surface.

The method of the present invention reduces the temperature of the steel core and improves the composite material while preventing the formation of needle-like transformations and the formation of tough oxides on the outer surface of the cladding material. It will be understood that this is indicative of effective cooling. Moreover, they all require neither chemical cleaning means such as pickling nor physical cleaning means, and can be cleaned by reducing the oxides after air cooling, for example in decomposed ammonia. It will be appreciated that this is done without creating any aggressive sponges.

Cooling can be carried out at a pressure other than atmospheric pressure, if necessary, and in this case, the boiling temperature of the water can be adjusted accordingly. Such modifications are within the scope of the present invention except in special cases. Additionally, certain additives can be added to alter the boiling point. As used herein, the term "coolant" and its boiling point includes both water with additives and water without additives, and such water may be at atmospheric pressure or under different pressures. The boiling point changes depending on the influence of additives or pressure.

For convenience of explanation, the apparatus has been described with respect to two different cladding pieces 18, 20; however, if desired,
It will be appreciated that one cladding piece or more than two cladding pieces can be used.

The core used here is rod-shaped, but it is generally rod-shaped and almost cylindrical in shape.
Other shapes can be used as required.

The above-described specific embodiments of the invention are for illustrative purposes only, and it will occur to those skilled in the art that various changes in detail may be made without departing from the claimed invention. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the primary main body of a product made according to the present invention, and FIG. 2 is an explanatory view schematically showing a part of the apparatus used in the main process of the present invention. 10... Steel core rod, 14, 16...
Joining roll, 18, 20... Cladding piece, 36...
...Power supply, 50... Clad product, 52... First overflow tank, 56... First cooling tank, 66... Second overflow tank, 72...
...Second cooling tank, 76...Third overflow tank.

Claims (1)

[Claims] 1 A steel core rod and at least one cladding piece made of another metal are heated, the cladding pieces are arranged around the core rod, and the cladding pieces are moved while the core rod and the cladding piece are moved. After solid state welding to the core rod and bonding, the clad steel rod is immersed in a first cooling liquid whose temperature is within the range of about 160°C to the boiling temperature of the cooling liquid, and then the first cooling A method of cladding a steel core rod with another metal, characterized in that the clad rod is immersed in a second cooling liquid having a lower temperature than the liquid. 2. The method according to claim 1, wherein the first cooling liquid and the second cooling liquid are additive-containing water or additive-free water. 3. The method of claim 2, wherein the temperature of the first cooling water is within the range of about 160° to 212°. 4. The method of claim 3, wherein the temperature of the second cooling water is about 80°C or less. 5 Claim No. 4 in which there are two cladding pieces
The method described in section. 6. The method of claim 5, wherein the first cooling is performed within the range of about 195ⓓ to 205ⓓ. 7. The method of claim 6, wherein the cladding material is a material selected from the group consisting of copper, copper alloys, nickel, and nickel alloys. 8. The method of claim 7, wherein in the first water cooling the temperature of the steel core rod is reduced to a temperature below about 1100°C. 9. The method according to claim 8, wherein the first water cooling is performed at approximately atmospheric pressure. 10. The method according to claim 9, wherein the cladding is carried out on a steel rod of either medium carbon steel or high carbon steel. 11 The cladding is made of steel rod having a carbon content of more than about 0.16%.
The method described in section. 12. The method of claim 11, wherein the water in the second water cooling is at about room temperature. 13. The method of claim 12, wherein the cladding rod passes through the first water cooling at a speed of about 45 to 60 feet per minute. 14. The method of claim 11, wherein the steel rod has a diameter of less than about 1/2 inch. 15. The method of claim 14, wherein each part of the clad steel rod remains cooled with heated water for a period of about 15 to 50 seconds. 16. The method of claim 15, wherein each part of the clad steel rod remains cooled with heated water for a period of about 25 to 45 seconds.