WO2017081824A1 - De-leading treatment method for lead-containing copper alloy and de-leading cored wire used in said method - Google Patents

Abstract

Copper alloys such as brass or bronze, primarily rod-shaped products for which free-cutting is required, contain a certain amount of lead. From the past, scraps of said products have been re-used at a high rate. For recycled use of said product scraps for low-lead products, a lead removal step is indispensable and development of lead removal technology is imperative. For lead removal from copper alloys, materials containing metal element calcium are known to be effective. But because of differences in specific gravity and melting point between the de-leading agent and the copper alloy, a de-leading method that is practicable at a mass production level was desired. To solve said problem, the present invention is a de-leading cored wire for the purpose of de-leading treatment of a molten copper alloy metal, the cored wire being characterized in that: a metal band that does not affect components of the molten copper alloy metal is used as a sheath material; the content is a de-leading agent alone and/or an auxiliary de-leading agent such as a Pb-Ca compound flocculant/flotation reagent, etc. that is necessary in the process; and the cored wire has physical properties that can withstand mechanical and continuous feeding by a cored wire-feeding device.

Description

Deleading treatment method of lead-containing copper alloy and leaded cored wire used in the method

The present invention relates to a lead-free cored wire used for lead removal treatment of molten lead-containing copper alloy and a lead removal treatment method using the same.

In order to obtain workability (free machinability) for copper alloys, mainly brass bars, it is effective to contain about 2 to 4 wt% of lead. The target used for the brass rod is, for example, a tap for waterworks, a processed part for various optical devices, or an automobile part. In recent years, regulations in the direction of reducing or eliminating lead contained in brass bars from the viewpoint of environmental regulations are being strengthened.

Although it is a well-known fact that it is possible to have a workability (free-cutting property) similar to that of a conventional lead-containing brass rod by including a metal such as bismuth as an alternative to lead, it is expensive. A product generally called lead-free using bismuth cannot compensate for all the conventional products in terms of performance. In addition, with regard to brass rods that are already used mainly in taps for waterworks, considering the effects on the human body, a product generally called low lead with a reduced lead content has been developed and used.

However, the ratio of these new products to the market is low, and most of them are the previous products. On the other hand, many copper alloy products containing brass are manufactured from remelting of scrap, and it is extremely difficult to manage the scrap by generated product. Therefore, it is highly possible that most of scrap generated from products made of lead-free or low lead is mixed with the raw material of the previous product.

As these countermeasures, a method has been proposed in which metallic element calcium and / or copper calcium alloy is added to a molten brass containing lead to remove lead as a compound with calcium (Patent Document 1). Also proposed is a method in which lead-free inclusions are produced by adding a lead-free material to the molten copper alloy, and then adding a desiliconizing agent to release the lead-containing inclusions, which are separated and levitated to eliminate them. (Patent Document 2). Further, a method has been proposed in which a tin blocking agent and then a deleading agent are added and mixed in a molten copper alloy, and lead-containing inclusions are similarly levitated and removed (Patent Document 3). Regarding the use of cored wire, for example, a method has been proposed in which a cored wire coated with a desulfurizing agent with an iron-based strip material and a sheath material is introduced into hot metal / molten steel and the desulfurizing agent reacts with the molten iron / molten steel to increase the desulfurization effect (Patent Document 4).

Japanese Patent Laid-Open No. 10-140254 Japanese Patent Laid-Open No. 2005-8970 JP 2006-161136 A JP 2008-95136 A

The method of Patent Document 1 is a method in which 300 kg of raw material is deleaded and removed with a small crucible, and a deleading agent is added at a time and left to perform component analysis. In addition, the method of Patent Document 2 uses 4 kg of bronze as an example, and 320 g of deleading agent and 150 g of desiliconizing agent are used to blow and supply nitrogen gas into the molten metal. At the same time, Patent Document 3 is an experiment using 5 kg bronze and 400 g deblocking material. These are all small-scale experimental methods, and are, for example, manually possible regardless of whether an additive is added or stirred.

Calcium metal is most effective for the purpose of deleading, but it is a water-reactive flammable substance that generates hydrogen when it comes into contact with water, especially when it is granular or powdery. Keeping it in a dry, cool and dark place and paying attention to the reactivity when thrown into the molten metal makes handling difficult. Calcium silicon is also a problem in handling in practical mass production because the same danger increases by making it granular or powdery.

In addition, these deleading agents (Ca density 1.55) and auxiliary agents have a small specific gravity and rise to a molten brass or bronze having a specific gravity of more than 8, and a sufficient deleading effect can be obtained simply by adding them. Cannot be obtained. Even if a method such as using a stirrer contributes technically, it is not established in practical mass production because it is expected that equipment will be installed and processing steps and time will be added.

As described in Patent Document 4, the cored wire known as an existing technology wraps an additive raw material necessary for deoxidation, desulfurization, and graphite spheroidization in a single or mixture form in an iron outer metal strip (sheath material). It is used in the steel industry and casting industry as a material that is put into hot metal to be processed and molten steel.

The contents used in conventional cored wires are a combination of various raw materials such as deoxidizers, desulfurizers, and graphite spheroidizers depending on the purpose of use, and the sheath material can be changed depending on the purpose and the object to be processed. Although it is possible, the outer metal strip used in products that are actually distributed in the market is only an iron sheet, and other metal (for example, aluminum) sheets that can theoretically be procured and used are the technical and cost of operation. Most have not been selected from the viewpoint of target and procurement difficulty.

In addition, the object of the present invention is the deleading of copper alloys, and iron, aluminum, etc. that have been used in the past can not be used because they affect the quality of the deleaded copper alloy. In this case, the sheath material to be selected is not only a component but also appropriately supplied to the molten metal by the cored wire supply device, so that the content after the shape processing to the cored wire is securely fixed, and it is torn during the supply. Physical properties such as strength (tensile strength), flexibility, and workability are required to prevent breakage and opening. In particular, when a cored wire is supplied by a cored wire supply device, a balance between strength and flexibility of the cored wire is required.

The main component of the deleading agent in the present invention is metallic calcium and / or calcium silicon, and the deleading auxiliary agent has a lower specific gravity than the molten copper alloy to be deleaded. Therefore, the expected deleading effect cannot be obtained because the reaction occurs only on the surface.

In order to obtain an effective deleading method, it is necessary to add gravity corresponding to the buoyancy of the deleading agent and set it in the molten metal. In general, the buoyancy in a fluid is obtained by the following equation 1.
(Formula 1)
F = ρVg
(F = buoyancy, ρ = fluid density, V = volume of object, g = gravity acceleration)

For example, the force required to settle 10 kgs of calcium metal with a density of 1.55 against a brass melt with a density (specific gravity) of 8.2 is determined by the resultant force obtained by subtracting the weight of the object from buoyancy.
(Formula 2)
F ′ = (ρ ₁ −ρ ₂ ) Vg
(Ρ ₁ = Brass density, ρ ₂ = Metal calcium density)
So
F ′ = [8.2 (g / cm ³ ) −1.55 (g / cm ³ )] × [10,000 (g) /1.55 (g / cm ³ )] × 9.8 (m / s ² )
= 420, 452 (g · m / s ² ) ≈43 kgf
It becomes.

In simple calculation, it is necessary to attach a weight of 43 kgs from directly above the molten metal at around 1000 ° C. or push it into the molten metal by mechanical force. Of course, in practical mass production, this value is considered to increase greatly depending on the target of the amount of molten metal processed and the amount of lead removal, and cannot be handled manually, requiring a large-scale device. In addition, it is necessary to prepare each time that the jig required to push into the molten metal is insoluble with respect to the temperature and components of the molten metal or that does not adversely affect the quality of the molten metal even when the molten metal is used. In terms of cost and work process increase, it is not suitable for practical mass production.

The present invention is a means and method for solving the above problems in order to perform lead removal in mass production of copper alloys. In the present invention, metal calcium or / and calcium silicon is coated with a metal sheath material, so that contact with moisture in the air is minimized, and the risk is reduced. By enabling automatic charging continuously over time, it has reduced and solved safety problems and handling problems in practical lead production. Here, the copper alloy refers to an alloy containing copper as a main component, and is mainly brass or bronze, but is not particularly limited thereto.

In the present invention, the cored wire including the deleading agent is first supplied to the molten metal to avoid the batch introduction of the deleading agent, minimizing the resistance per unit time against the buoyancy of the molten metal, The lead-free agent is dispersed in the core, the lead-free lead is effectively executed, and the cored wire performance that can be mechanically and continuously supplied by the cored-wire feeding device is realized, eliminating dangerous work directly on the manpower or molten metal. To solve the problem.

Therefore, in the present invention, a granular or powdery deleading agent and / or Ca compound, a Pb—Ca compound aggregating / floating agent, tin block material, copper, zinc, tin, or copper containing the metal element calcium In addition, a granular or powdery deleading auxiliary agent containing at least one of zinc or tin compounds, and a sheath material composed of copper or a copper alloy, each of the deleading agent and the deleading auxiliary agent alone or in combination. A lead-free copper alloy deleading method is proposed, in which a lead-free cored wire configured by coating is sequentially fed into a molten copper alloy containing lead, and then deleaded.

Further, a lead-free cored wire constituted by coating the deleading agent with the sheath material and a lead-free cored wire constituted by covering the deleading auxiliary agent with the sheath material are supplied into the molten metal. We propose a deleading method characterized by settling and deleading.

Further, a lead removal cored wire constituted by covering at least one of the lead removal agent and / or the lead removal auxiliary agent with the sheath material is supplied and settled in the molten metal once or a plurality of times to remove the lead. We propose a deleading method characterized in that

Also comprised of a sheath material made of copper or copper alloy having a tensile strength of 150 to 600 N / mm ² and stretchability of 15 to 60%, and a granular or powdered deleading agent containing metallic calcium or / and calcium silicon. Then, the present invention proposes a lead-free cored wire characterized in that the sheath material is coated with the de-leading agent.

In addition, a sheath material composed of copper or a copper alloy having a tensile strength of 150 to 600 N / mm ² and stretchability of 15 to 60%, an agglomeration / floating agent of Ca compound and Pb—Ca compound, tin block material, copper, zinc , Tin, or a particulate or powdery deleading adjuvant containing at least one of copper, zinc or tin compounds, and the sheath material is coated with the deleading adjuvant We propose a leaded cored wire.

In addition, a sheath material made of copper or copper alloy having a tensile strength of 150 to 600 N / mm ² and an extensibility of 15 to 60%, and a granular or powdery deleading agent and a Ca compound containing metallic calcium or / and calcium silicon A Pb—Ca compound agglomeration / floating agent, a tin block material, copper, zinc, tin, or a particulate or powdery deleading auxiliary containing at least one of copper, zinc or tin compounds, A lead-free cored wire is proposed in which the sheath material is coated with the lead-free agent and the lead-free auxiliary agent.

Also, we propose a lead-free cored wire characterized in that the diameter of the lead-free cored wire is 4 to 30 mm.

Also, we propose a lead-free cored wire characterized in that the sheath material of the lead-free cored wire has a thickness of 0.1 to 3 mm.

In addition, a granular or powdery deleading agent containing calcium metal and / or calcium silicon and / or agglomeration / floating agent of Ca compound and Pb-Ca compound by shape processing of a sheath material made of copper or copper alloy , A tin block material, copper, zinc, tin, or a granular or powdery deleading auxiliary agent containing at least one of copper, zinc, or a tin compound is closely fixed to the sheath material, and the deleading agent and / or The present invention proposes a method for producing a lead-free cored wire, wherein the lead-free auxiliary agent is fastened so as not to move with respect to the sheath material.

According to the present invention, the structure having an appropriate strength and flexibility in consideration of the work-hardening property of the sheath material can prevent the cored wire from being torn, broken, and opened, and thus, continuous to the molten metal. Supply can be carried out automatically, enabling practical mass-production deleading treatment of molten copper alloy, and further reducing the difficulty of mixing deleading agent with low specific gravity and large amount of molten metal with high specific gravity. In addition, it was possible to reduce the risk of working on the molten metal by using a large amount of a highly reactive deleading agent.

Schematic explanatory diagram of a cored wire supply device for carrying out the present invention Cross-sectional explanatory view of a lead-free cored wire showing one embodiment of the present invention Cross-sectional explanatory view of a lead-free cored wire showing one embodiment of the present invention Cross-sectional explanatory view of a lead-free cored wire showing one embodiment of the present invention Cross-sectional explanatory view of a lead-free cored wire showing one embodiment of the present invention

The cored wire supply device used in the present invention will be described with reference to FIG. The cored wire supply device 10 is a device for supplying the lead-free cored wire 1 to a processing vessel 11 such as a melting furnace for processing the lead-containing copper alloy molten metal which is the object of the present invention. The lead-free cored wire 1 is drawn out from a coil 12 wound in a coil shape and fed into a processing container 11 by a feeder 13.

The feeder 13 is installed on the gantry 14 and is configured to draw the lead-free cored wire 1 from the coil 12 and into the molten metal 17 accommodated in the processing container 11. The feeder 13 can employ various mechanisms, but the lead wire cored wire 1 is sandwiched by a plurality of rolls and a plurality of feed rolls rotated by a motor, and the above-described drawing and feeding are continuously performed. Mechanism.

A plurality of guides 15 for the lead-free cored wire 1 are provided at appropriate positions on the gantry 14, and the lead-free cored wire 1 drawn from the coil 12 is smoothly drawn out to the feeder 13. A guide pipe 16 is provided between the feeder 13 and the processing container 11, and is responsible for feeding the lead-free cored wire 1 and continuously feeding it into the molten metal 17. Further, the guide pipe 16 can be supported by a support arm 141 extending from the gantry 14.

The lower end of the guide pipe 16 may protrude into the processing container 11 on the assumption that it does not touch the molten metal. The lead-free cored wire 1 is preferably fed close to the bottom of the processing vessel 11, and the feeding speed is adjusted in consideration of the material and thickness of the sheath material 4, near the bottom of the processing vessel 11. It is preferable to dissolve. In the lead-free cored wire 1 used in the present invention, metallic calcium and calcium silicon are used alone or in combination as the lead-free agent 2. The deleading agent 2 can be granular or powdery.

Further, as shown in FIGS. 2 to 5 which are sectional views of the lead-free cored wire, the lead-free agent 2 and the lead-free auxiliary agent 3 are mixed and mixed with the contents of the lead-free cored wire, that is, the constituent elements. (Figs. 2 and 3), however, it is also possible to make an independent separate lead-free cored wire 1 containing only one of the de-leading agent 2 or the de-leading auxiliary agent 3 (FIGS. 4 and 5). This suggests that the use of a plurality of lead-free cored wires 1 can flexibly cope with various types of lead-free treatment matrices produced in practical mass production. Accordingly, in the present invention, the lead-free cored wire 1 used for lead removal includes those in which the lead removal agent 2 and / or the lead removal auxiliary agent 3 are used alone or in combination.

In the present invention, a sheath material that covers a deleading agent 2 and / or a deleading auxiliary agent 3 with a metal that does not affect the composition of the copper alloy, such as copper, brass, bronze, or a copper alloy containing zinc or tin, etc. 4 is used.

The copper or copper alloy sheath material used in the present invention exhibits high work hardening when processed, unlike iron cored wires that have been manufactured using existing technology. This is a phenomenon in which the hardness of the metal increases due to plastic deformation when stress is applied to the metal, and this characteristic is indicated by the magnitude of the work hardening coefficient. In contrast to 0.15 for normal carbon steel (0.6C steel), 65/35 brass, which is one of the sheath materials 4 used in the present invention, shows a value of 0.53, which is three times or more. This means that when a copper alloy is processed as the sheath material 4, the functions such as flexibility expected as the lead-free cored wire 1 are lost.

In general, the tensile strength and stretchability vary greatly depending on the material. Therefore, the lead wire cored wire 1 must be able to withstand actual use by taking into account the type and physical characteristics of the sheath material 4 and changing the cored wire manufacturing conditions. . In order to solve this problem, in the present invention, the metal used for the sheath material 4 is tested, and the tensile strength as a physical property required for the lead-free cored wire is in the range of 150 to 600 N / mm ² and stretched. Regarding the sex, it was clarified that it is desirable to be 15 to 60%. If the tensile strength is less than 150 N / mm ² , there is a large risk of cutting, and if it exceeds 600 N / mm ² , it is too strong and affects the production of lead-free cored wire. The use of was also difficult. With regard to stretchability, if it is less than 15%, there is no room for deformation and it is difficult to produce and supply lead-free cored wire. Arise.

Also, the diameter of the lead-free cored wire is preferably 4 to 30 mm for the purpose of facilitating the manufacturing process of the lead-free cored wire and maintaining the shape during supply. Furthermore, for the same purpose, it is desirable that the thickness of the sheath material 4 used in the present invention is in the range of 0.1 mm to 3.0 mm. If it is less than 0.1 mm, the strength is weak, and there is a risk of breaking and cutting. If it is greater than 3.0 mm, it becomes difficult to bend as the lead-free cored wire 1, and it becomes difficult to manufacture and supply the cored wire. .

Furthermore, the material and thickness of the sheath 41 used in the present invention is more effective in considering the position and time of melting because the contents act more efficiently in the molten metal to be deleaded. The optimum one can be selected within the above proposed range considering the matrix of characteristics and deleading effect. In addition, regarding the material of the sheath material 4, those described in JIS standard product numbers C1020-1441 and C2100-4640 correspond to the materials used, and it is convenient to use them in practice.

The following various additives can be provided as the lead removal auxiliary agent 3 that enhances the lead removal effect in the contents of the leaded cored wire. The deleading adjuvant 3 can be granular or powdery. For example, Ca compound 31 such as CaF2, CaCO3, CaO, etc., and Pb-Ca compound agglomeration / floating agent 32, which contributes to fixation of the deleading agent in the cored wire for deleading and is used as a post-reaction agent Copper for deleading treatment that contributes to fixing of deleading agent in core lead wire for deleading and adjustment of molten metal components after deleading, such as minerals containing sodium fluoride and alumina silicate glass called tin blocking agent Metals such as copper, zinc, tin, etc., or their compounds 34, which are components constituting the alloy itself. These can be included in the lead-free cored wire by selecting the desired additive. Also, a lead-free cored wire containing only these additives, for example, only Ca compound 31 (FIG. 5), only a coagulating levitation agent, only a tin blocking agent, and only a metal / compound such as copper is manufactured. The selection is also one aspect of the present invention. A cored wire including only these deleading auxiliary agents can also be referred to as a deleading auxiliary cored wire. As described above, the lead-free cored wire 1 is obtained by coating one or more types of deleading agents and one or more types of deleading auxiliary agents with a sheath material, and one or more types of deleading agents with a sheath material. And one or more deleading aids coated with a sheath material. In addition, one or more types of deleading agents and one type of deleading aid are covered with a sheath material, and one type of deleading agent and one or more types of deleading aids are covered with a sheath material. It is.

When the lead removal agent 2 and the lead removal auxiliary material 3 are integrated and fixed on the cored wire 1, the lead wire cored wire 1 and the content of lead removal are made to exhibit its extensibility when processing the leadless cored wire 1. The agent 2 and the deleading adjuvant 3 are condensed while being adhered. As one method, the sheath material 4 may be fastened and covered by, for example, caulking both ends 5.

In order to confirm the effectiveness of the present invention, the test shown in Table 1 was conducted using the cored wire supply device 10 shown in FIG.

In Examples 1 and 2 described above, the lead-free cored wire 1 was continuously supplied into the molten brass 17. The lead-free cored wire 1 of the present invention can be charged into the molten metal in a predetermined quantity (length) without causing problems such as tearing, breaking, and opening, and the indicated lead removal was performed. From the examples, it is judged that it is possible to manufacture the optimum lead-free cored wire according to the weight of the molten metal, the temperature, and the shape of the container, and to set the supply conditions. From the results of the above examples, it was proved that deleading in units of several tens of kilograms on a mass production scale using an actual machine that could not be realized in the prior art example was possible. In addition, since there was no problem of tearing, breaking, opening, etc. while using a sheath material that is not a prior art, the characteristics required for the sheath material specified in this patent are: It is judged that the conditions that can withstand the supply by the machine are satisfied.

In addition, in the said Example, although the test using a brass was done, it is clear that it is applicable not only to brass but copper alloys, such as bronze.

In view of the current situation that many copper alloy products containing brass are manufactured from scrap remelting, it is extremely important to remanufacture scrap as a raw material to produce a high quality copper alloy. The present invention is very efficient in removing lead contained in a copper alloy, enables mass production of a good-quality copper alloy, and improves the quality of the copper alloy product and thereby reduces the cost of the manufactured product. Can be practically used.

Claims (9)

1. A granular or powdery lead removal agent and / or Ca compound, a coagulation / floating agent of Pb—Ca compound, tin block material, copper, zinc, tin, or a compound of copper, zinc, or tin, containing metal element calcium Deleading consisting of a granular or powdery deleading aid containing at least one of them, and covering each of the deleading agent and deleading aid alone or in combination with a sheath material composed of copper or a copper alloy A lead-free copper alloy deleading method characterized in that a cored wire is sequentially supplied into a molten copper alloy containing lead, and then precipitated and deleaded.
2. The lead-free cored wire configured by coating the deleading agent with the sheath material and the lead-free cored wire configured by covering the deleading auxiliary agent with the sheath material are supplied and settled in the molten metal. The lead removal processing method according to claim 1, wherein the lead removal treatment is performed.
3. A lead removal cored wire configured by covering at least one of the lead removal agent and / or the lead removal auxiliary agent with the sheath material is supplied and settled in the molten metal once or a plurality of times to perform the lead removal treatment. The lead removal processing method according to claim 1 or 2, wherein
4. A sheath material composed of copper or a copper alloy having a tensile strength of 150 to 600 N / mm ² and an extensibility of 15 to 60%, and a granular or powdery deleading agent containing metallic calcium or / and calcium silicon; A cored wire for lead removal, wherein the sheath material is coated with the lead removal agent.
5. Sheath material composed of copper or copper alloy with tensile strength of 150 to 600 N / mm ² and stretchability of 15 to 60%, agglomeration / floating agent of Ca compound and Pb-Ca compound, tin block material, copper, zinc, tin Or a granular or powdery deleading adjuvant containing at least one of copper, zinc or tin compounds, and the sheath material is coated with the deleading adjuvant. Cored wire for lead removal.
6. Sheath material composed of copper or copper alloy having a tensile strength of 150 to 600 N / mm ² and stretchability of 15 to 60%, and a granular or powdery deleading agent and Ca compound containing calcium metal and / or calcium silicon, Pb A Ca-coagulating / floating agent, a tin block material, copper, zinc, tin, or a granular or powdery deleading aid containing at least one of copper, zinc or tin compounds, A cored wire for lead removal, wherein the sheath material covers a lead agent and the lead removal auxiliary agent.
7. The lead-free cored wire according to any one of claims 4 to 6, wherein the lead-free cored wire has a diameter of 4 to 30 mm.
8. The lead-free cored wire according to any one of claims 4 to 7, wherein the sheath material of the lead-free cored wire has a thickness of 0.1 to 3 mm.
9. A granular or powdery deleading agent containing calcium metal and / or calcium silicon and / or agglomeration / floating agent of Ca compound, Pb-Ca compound, tin by shape processing of sheath material composed of copper or copper alloy, tin A granular or powdery deleading auxiliary agent containing at least one of a block material, copper, zinc, tin, or a compound of copper, zinc, or tin is tightly fixed to the sheath material, and a deleading agent and / or deleading A method for producing a lead-free cored wire, wherein the auxiliary agent is fastened so as not to move relative to the sheath material.

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