Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/02—Making non-ferrous alloys by melting
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C18/00—Alloys based on zinc
  • C22C18/02—Alloys based on zinc with copper as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
  • C22F1/165—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon of zinc or cadmium or alloys based thereon

Definitions

• the present invention relates to a deformed zinc alloy and a process for the preparation thereof, and more particularly to a zinc-copper-based deformed zinc alloy which can be used for the manufacture of nuts and nuts for the air-conditioning industry and a method for producing the same. Background technique
• Air conditioning is a widely used household and office appliance that consists primarily of refrigerant, compressors, piping and various valves.
• the wrought zinc alloy of the invention is mainly used for replacing the traditional copper alloy, and is used for manufacturing various hexagonal nuts and nuts used in air conditioners. These hex nuts and nuts are mainly used for sealing and connecting the shut-off valve and the four-way valve.
• Zinc alloys may be a possible alternative, but since metal zinc is a hexagonal crystal structure with less slip, the cast state is a relatively brittle and less rigid metal. Alloying elements such as aluminum, copper, and magnesium are usually added to the zinc matrix to increase the strength of the zinc alloy and improve the overall performance. Commonly used die-casting and gravity-casting zinc alloys are all metal materials with zinc-aluminum as the main alloying element. There is a clear tendency of intergranular corrosion, low electroplating yield, and low creep strength, low temperature brittleness, etc. Used as a structural material, most of it is used as a decorative function or appearance product.
• "Hot-impregnated surface-formed olive-green zinc alloy coating” disclosed in Japanese Patent Publication No. JP63241132A proposes a zinc alloy containing Mn 0.2-0.8 wt.%, Cu 0.05-1.0 wt%, and the balance being zinc.
• the zinc herein preferably uses zinc having a purity of >99.99%, and the content of Pb in the zinc alloy is preferably 0.005 wt%.
• the zinc alloy coating is corrosion resistant and has an olive color. Its main application areas are hot dip coating and surface coating. Further, as disclosed in Chinese Patent Application No.
• the zinc alloy is composed of the following components by weight: Copper 0.5 ⁇ 3.0%, manganese 0.01 ⁇ 2.0%, titanium 0.05 ⁇ 0.3%, the balance is zinc and the total amount is less than 0.05% impurities.
• the zinc alloy component may further contain: X 0.01 to 0.5% by mass, and X is at least one of aluminum and a rare earth element (Ce+La).
• the preparation method is the smelting by the cover protection method, and the alloying elements are added in the form of pure zinc, Zn-Cu, Zn-Ti, Cu-Mn, pure aluminum, Ce+La composite rare earth; the melting temperature is 650-740 ° C; -480 ° C casting; ingots after 350-380 ° C are thickened and annealed for 6-10h; multi-pass hot rolling at 220-280 ° C, total deformation of 60-95%; cold rolling, total deformation The amount is 50-80%; after rolling, it is annealed at 180-200 ° C for 2-3 h, and finally the product of the strip structure is obtained.
• Bi plays a major role in improving the cutting performance in zinc alloys.
• Sun Liping in the Journal of Chinese Nonferrous Metals, Vol. 21, No. 7 (2011), reported the microstructure and properties of the free-cutting Zn-Cu-Bi alloy.
• the main component of the alloy is Zn-Cu-Mn. -Bi-Mg-Ti-Al, which contains aluminum.
• the cast zinc-based alloy material has good formability, it has poor comprehensive performance indexes such as strength, hardness and workability, and cannot be used as an air-conditioning hex nut or nut. It is mainly used as a die-casting product for appearance parts.
• Figure 3 shows a metallographic photograph of the Zn-Al-based alloy cast structure. It can be seen from the figure: The coarse HCP structure indicates that the material has obvious brittleness and is not suitable for plastic forming.
• Table 1 shows the comparison of the mechanical properties of a typical cast alloy Zn-4Al-0.05Mg, the American brand name ZAMAK3# and the lead brass representative C3604.
• the first technical problem to be solved by the present invention is to provide a deformed zinc alloy for the current state of the art, replacing lead brass at a lower cost for manufacturing nuts and nuts for the air conditioning industry, and solving the problem of lack of copper resources. .
• a second technical problem to be solved by the present invention is to provide a method for producing a zinc-copper-based deformed zinc alloy of the present invention.
• the deformed zinc alloy characterized in that the composition by weight is:
• the balance is zinc and unavoidable impurity elements; the total amount of unavoidable impurity elements is less than 0.01%.
• the zinc alloy microstructure is mainly composed of a zinc matrix primary phase and an intermetallic compound dispersed between the primary phases; the primary phase is an HCP structure, the intermetallic compound is a fine ZiuCu and Zn 9 Mn; and the volume content of the Zi Cu phase 5%-55%, the volume content of the Zn 9 Mn phase is 0.1%-5%, and the rest is the primary phase; the average grain size of the primary phase is 15 to 35 microns, and the average grain size of the intermetallic compound is 5 ⁇ 15 microns.
• the average grain size of the intermetallic compound structure refers to the total average grain size of the intermetallic compounds of Zr ⁇ Cu and Zn 9 Mn.
• the invention adds Cu, Mn to the matrix of zinc, and forms a fine high-strength, high-hardness intermetallic compound dispersed in the matrix of the zinc alloy, thereby improving the strength and increasing the creep resistance;
• the trace amount of Co is dissolved in the matrix of zinc to form the HCP phase, which can act as a solid solution strengthening.
• Figure 1 shows the effect of copper content on the strength of Zn( 99 .78 . x )Cu x Mn Q . 2 Co a()2 alloy.
• Figure 2 shows the copper content versus Zn ( 99.78-x)Cu x Mno. 2 Coo.o2 alloy ductility, table 2 Effect of Mn content (94. 98-x) 5 Mn x Coo.o2 alloy strength, hardness and elongation of the Cu Zn.
• composition of the above zinc alloy by weight is:
• the amount of lanthanum is zinc and inevitable impurity elements.
• the ZmCu phase has a volume content of 10% to 30%, and the Zn 9 Mn phase has a volume content of 1% to 4%.
• the grain size of the Zn 9 Mn phase is preferably from 1 to 3 ⁇ m.
• the technical solution adopted by the present invention to solve the above second technical problem is: the method for manufacturing the above-mentioned deformed zinc alloy, characterized in that the Cu, Mn, Co, and zinc are first added as a copper manganese and a copper-zinc intermediate alloy. After casting, a deformed zinc alloy casting blank can be obtained.
• the heating method of the casting can be a reverberatory furnace, an intermediate frequency heating furnace or a power frequency heating furnace, and the casting temperature is 500 ° C-60 (rC, the crystallization process can be hard mold casting, continuous casting Or semi-continuous casting, the casting rate is 2-5 m / h; the slab is extruded and stretched to obtain a deformed zinc alloy, and the extrusion speed during extrusion is 0.1-3.5 mm/s, the extrusion temperature It is 150 ° C-35 (TC, extrusion ratio is 10-256; the pass processing rate of stretching is 5-15%, and the total processing rate is up to 80%.
• TC extrusion ratio
• the pass processing rate of stretching is 5-15%
• the total processing rate is up to 80%.
• the invention adopts the method of adding copper-zinc and copper-manganese intermediate alloy to lower the melting point, thereby ensuring the requirement of the alloy composition range and significantly reducing the burning loss of zinc element; at the same time, the copper and manganese elements can be made of metal.
• the inter-compound enhanced form is present uniformly in the zinc-based alloy matrix.
• the invention realizes the deformed zinc alloy suitable for the shape and specification of the air conditioner nut nut by hot extrusion, drawing, heat treatment and joint drawing process of the slab, and the characteristic is that the alloy is realized by these treatment processes.
• the microscopic metallographic structure changes from cast state to processed state, and the material changes from brittle material to ductile material, and the mechanical properties are obviously improved.
• Fig. 6 shows the metallographic structure of the Zn-Cu-Mn-Co alloy having the chemical composition of the zinc alloy of the present invention in a cast state. It can be seen that the microstructure is coarse, and the intermetallic compound is distributed in the matrix in a coarse needle-like structure.
• the metallographic structure of the Zn-Cu-Mn-Co zinc alloy of the present invention after hot extrusion and drawing processing is shown in Fig. 7, as can be seen from Fig. 7: Zn after extrusion and drawing
• the metallographic structure of the -Cu-Mn-Co zinc alloy consists of a hexagonal structure of deformed structure and a dispersed intermetallic compound. The structure is characterized by a certain directionality, and the coarse needle-like structure is refined.
• Figure 8 shows the distribution of Zi ⁇ Cu and Zn 9 Mn in zinc matrix characterized by scanning electron microscopy.
• the grain size of HCP primary phase and intermetallic compound Z Cu is relatively large, accounting for a large volume fraction, while Zn 9
• the grain size of the Mn phase is relatively small, and the volume fraction is small.
• the microstructure of the deformed zinc alloy of the present invention is mainly composed of a zinc matrix HCP primary phase and a ZmCu phase and a Zn 9 Mn phase which are substantially uniformly dispersed between the primary phases; the volume of the Zi ⁇ Cu phase is 5%-55. The volume content of %, Zn 9 Mn phase is 0.1%-5%, and the rest is primary phase; the average grain size of the primary phase is 15 ⁇ 35 microns, the grain size of Zn 9 Mn phase is smaller, and the ZIL I phase is larger. The total average grain size of the two intermetallic compounds is 5 to 15 microns.
• the alloy contains cobalt
• cobalt and zinc are solid-dissolved to form a HCP primary phase, so that the cobalt-containing and cobalt-free deformed zinc alloys have substantially the same metallographic structure.
• the inventors of the present application have found through extensive experiments that the processing conditions and component contents have an important influence on the metallographic structure, If the composition is not suitable, it is difficult to obtain a deformed zinc alloy having the characteristics of the present invention by changing the processing conditions, and the processing conditions have a direct influence on the metallographic structure of the deformed zinc alloy of the present invention, and finally based on a large number of tests.
• the composition and processing conditions of the zinc alloy of the present invention were determined.
• the use of the deformed zinc alloy described above is performed by machining, hot stamping or cold rolling to form a semi-finished product, and the semi-finished product is refined, tapped and then electroplated to form a hexagon for the air conditioning industry. Nut or nut wide mouth;
• the hot stamping temperature is 200 ⁇ 300 ⁇
• the cold heading is 3-5 station processing.
• the forming process of the nut and the nut can be machined, hot forged or cold formed.
• Zinc alloy hex nuts/nuts can be machined by CNC machine tools, automatic machine tools and special machine tools.
• the raw materials are linear bars, and coolant is used in the machining process to improve machining efficiency.
• Hot forging is carried out by using a straight bar, which is heated, stamped into a blank, and then finished by an instrument vehicle. The cold heading adopts the loop line product. After the blanking, after the multi-station is punched into the blank, the finished product is finished with the instrument vehicle.
• the invention adopts a process of adding zinc-copper and copper-manganese intermediate alloy in the process of casting, so that the casting structure of the zinc-based alloy is refined, and the intermetallic compound can be uniformly distributed in the matrix of the zinc.
• the brittleness of the material is improved, the subsequent processing is facilitated, the burning of zinc in the high-temperature melting is avoided, and the yield of the material is improved; on the other hand, plastic processing such as extrusion and drawing is performed.
• the alloy is transformed from a brittle zinc-based alloy into a tough structural state, and the comprehensive performance index of the zinc-based alloy material is significantly improved.
• the present invention determines a suitable alloy chemical composition, it is processed. After that, a deformed zinc alloy having a specific characteristic metallographic structure can be obtained, and these specific metallographic structures make the overall performance of the deformed zinc alloy of the present invention stably improved and improved.
• the zinc alloy-based alloy of the present invention does not have the most commonly used alloying element Al in the conventional zinc alloy, the intergranular corrosion which is common in the conventional zinc-aluminum alloy is effectively avoided, and the chemical uniformity and stability of the alloy are improved.
• FIG. 1 is a graph showing the relationship between the copper content of the present invention and the strength of Zn(99.78-X)CuXMn0.2Co0.02 alloy
• FIG. 2 is a graph showing the copper content of the present invention for Zn(99.78-X)CuXMn0.2Co0.02 alloy®.
• FIG. 3 is a metallographic structure of a Zn-Al based casting alloy ZAMAK3# in the background art of the present invention, which is a typical primary dendritic structure, indicating that the material is brittle;
• Figure 5 is a metallographic structure of a deformed zinc alloy in a 10% oxalic acid medium after 24 hours, and no significant intergranular corrosion is observed;
• Figure 6 is a metallographic structure of a typical cast zinc alloy having the chemical composition of the zinc alloy of the present invention, the structure of which is coarse, and the intermetallic compound is distributed in the matrix in a coarse needle-like structure;
• Figure 7 is a metallographic structure of a deformed zinc alloy of the present invention, which is composed of a deformed structure of a hexagonal structure and an intermetallic compound dispersed;
• Figure 8 is a distribution of Zi ⁇ Cu and Zn 9 Mn characterized by scanning electron microscopy in a deformed zinc alloy matrix of the present invention. detailed description
• the molten component is Mn: 0.5%, Cu: 2.0%, Co: 0.1%, and the balance of Zn, which is added in the form of pure zinc, zinc-copper intermediate alloy, copper-manganese intermediate alloy, cobalt wire, and a reflection melting furnace of 80 kg capacity is used.
• the tensile strength of the finished bar product was 400 MPa, the elongation was 16%, and the Vickers hardness was Hvl05.
• the metallographic structure of the finished product was observed by scanning electron microscopy. Considering the composition of the alloy, the volume content of the Z Cu phase was determined to be 5%, the volume content of the Zn 9 Mn phase was 5%, and the rest was the primary phase.
• the nuts prepared in this example were tested for their properties under the same test conditions as those of lead brass (C3604) and cast zinc aluminum (ZAMAK3#). The performance parameters are shown in Table 3.
• the molten component is Mn 0.01%, Cu: 9.5%, Co: 0.02% and the balance of Zn, which is added to the medium-frequency melting furnace of 50 kg capacity in the form of pure zinc and zinc copper, copper-manganese intermediate alloy and cobalt wire.
• a slab was made using a hard mold with a diameter of 90 mm. After the slab was peeled, it was extruded into a round blank of ⁇ 27.5 mm on an 800T extruder at a pressing speed of 0.1 mm s.
• the extrusion temperature was 150 ° C, the extrusion ratio was 10; and the finished bar was stretched to ⁇ 19.0 mm, the pass processing rate of the drawing was 8.6%, and the total processing ratio was 52%.
• the finished bar has been tested to have a tensile strength of 490 MPa, an elongation of 10%, and a Vickers hardness of Hvl35.
• the metallographic structure of the finished product was observed by scanning electron microscopy. Considering the composition of the alloy, the volume content of the Z Cu phase was determined to be 55%, the volume content of the Zn 9 Mn phase was 0.1%, and the rest was the primary phase.
• Hot stamping of the finished bar hot stamping temperature of 220 ° C, drilling, shaping, tapping, final plating to make 1.5 pieces of finished nut / nut for air conditioning, the nut / nut resistant to neutral salt spray 1000 More than an hour.
• Example 3 Hot stamping of the finished bar, hot stamping temperature of 220 ° C, drilling, shaping, tapping, final plating to make 1.5 pieces of finished nut / nut for air conditioning, the nut / nut resistant to neutral salt spray 1000 More than an hour.
• the molten component is Mn: 0.1%, Cu: 8.0%, Co: 0.05% and the balance of Zn, which is added to the 80-kilometer medium-frequency melting furnace in the form of pure zinc, zinc-copper intermediate alloy, copper-manganese intermediate alloy and cobalt wire. After completely melting at 600 Torr, it was cast into a slab using a die of 170 mm in diameter.
• the slab After the slab is passed through the flat head and the wagon, it is extruded into a circular blank of ⁇ 15.0 mm on an extruder of 1,250 tons, the extrusion speed is 3.0 mm/s, the extrusion temperature is 300 ° C, and the extrusion ratio is 128; After further stretching to H2.5 mm, the pass pass rate of the drawing was 8.2%, and the total processing rate was 30%. Get the finished circle. After testing, the coil has a tensile strength of 475 MPa, an elongation of 12%, and a Vickers hardness of Hvl25.
• the metallographic structure of the finished product was observed by scanning electron microscopy.
• the volume content of the Zn4Cu phase was determined to be 40%, the volume content of the Zn 9 Mn phase was 1.5%, and the rest was the primary phase.
• Example 4 The above-mentioned coil wire is subjected to cold heading processing, drilling, tapping, cold heading, and 4-station processing, and finally, 1.5 pieces of hexagonal nuts/nuts for air conditioning are electroplated.
• the hex nut/nut finish is resistant to neutral salt spray for more than 1000 hours.
• the molten component is Mn: 0.2%, Cu: 6.0% and the balance of Zn. It is added to the medium-frequency melting furnace of 800 kg capacity in the form of pure zinc and zinc-copper intermediate alloy, copper-manganese intermediate alloy, and completely melted at 550 °C. Thereafter, a slab was cast at a rate of 4 m/hr using a horizontal continuous casting having a diameter of 170 mm.
• the extrusion speed was 3.5 mm/s
• the extrusion temperature was 350 ° C
• the extrusion ratio was 61
• the pass processing rate of the drawing is 5.3%
• the total processing rate is 33%.
• the tensile strength of the finished bar product is 455 MPa
• the elongation is 13%
• the Vickers hardness is Hvll5.
• the metallographic structure of the finished product was observed by scanning electron microscopy. Considering the composition of the alloy, the volume content of the ZI14CU phase was determined to be 35%, the volume content of the Zn 9 Mn phase was 2.5%, and the rest was the primary phase.
• the bar finished product was turned, drilled, tapped and plated to make a hex nut/nut product for air conditioning. After testing, the hex nut/nut finished product was resistant to neutral salt spray for more than 1000 hours.
• a material having a composition of Mn: 0.3%, Cu: 3.0%, Co: 0.07%, and the balance Zn is added to a 1000 kg capacity power frequency melting furnace in the form of pure zinc and zinc copper, copper manganese intermediate alloy, and cobalt wire. After complete melting at 580 ° C, a cast slab was cast at a speed of 3.5 m/hr using a semi-continuous method of 170 mm diameter.
• the slab After the slab is passed through the flat head and the wagon, it is extruded into a ⁇ 16.5mm round bar on a 1000 ton extruder with an extrusion speed of 2 mm/s, an extrusion temperature of 200 ° C, and an extrusion ratio of 106;
• the product was further drawn into a finished bar of ⁇ 16.0 mm, and the pass rate of the pass was 6.0%.
• the tensile strength of the finished bar is 430 MPa, the elongation is 13%, and the Vickers hardness is ⁇ 110.
• the metallographic structure of the finished product was observed by scanning electron microscopy.
• the volume content of the ZI14CU phase was determined to be 10%, and the volume content of the ⁇ 9 ⁇ phase was 3.5%, and the rest was the primary phase.
• the finished bar is hot-punched, turned, drilled, tapped and plated to produce a finished hex nut/nut for air conditioning.
• the hex nut/nut is resistant to neutral salt spray for more than 1000 hours.
• the above hot stamping temperature is 220 °C.
• the melting composition is Mn: 0.4%, Cu: 3.5%, Co: 0.01% and the balance of Zn, added to the 1500 kg capacity power frequency melting furnace in the form of pure zinc and zinc-copper intermediate alloy, copper-manganese intermediate alloy and cobalt wire.
• Mn 0.4%
• Cu 3.5%
• Co 0.01%
• Zn the balance of Zn
• the slab After the slab is cut by a sawing machine, it is extruded into a ⁇ 12.5mm round blank on a 2,500 ton extruder with an extrusion speed of 3.5 mm/s, an extrusion temperature of 250 ° C, and an extrusion ratio of 256; Drawing to a ⁇ 11.7 mm loop product, the pass rate of the pass was 7.1%, and the total processing rate was 13%.
• the product has a tensile strength of 470 MPa, an elongation of 10%, and a Vickers hardness of Hvl l5.
• the microstructure of the finished product was observed by metallographic microscope. Considering the composition of the alloy, the volume content of the ZI14CU phase was determined to be 16%, the volume content of the ⁇ 9 ⁇ phase was 3.5%, and the rest was the primary phase.
• the coiled product is cooled, turned, drilled, tapped and plated to produce a finished hex nut/nut for air conditioning.
• the nut/nut is resistant to neutral salt spray for more than 1000 hours.
• the above cold heading is processed by 3 stations.
• the melting composition is Mn: 0.3%, Cu: 5.0%, Co: 0.0005% and the balance of Zn, added to the 1500 kg capacity power frequency melting furnace in the form of pure zinc and zinc-copper intermediate alloy, copper-manganese intermediate alloy and cobalt wire.
• a slab was produced at a speed of 5 m / h using a continuous casting method of 200 mm in diameter.
• Slab blank saw After the bed is discharged, it is extruded into a ⁇ 18.0mm round blank on a 2500 ton extruder with an extrusion speed of 3.5 mm/s, an extrusion temperature of 250 ° C, an extrusion ratio of 123, and a drawing to ⁇ 8.0.
• the pass rate of the pass is 15.0%, and the total processing rate is 80%.
• the tensile strength of the coil product is 465 MPa, the elongation is 12%, and the Vickers hardness is observed by scanning electron microscopy.
• the composition of the alloy is determined by combining the composition of the alloy to determine the volume content of the ZH4CU phase is 30%, ⁇ 9 ⁇ phase. The volume content is 3.5%, and the rest is the primary phase.
• the coiled product is cooled, turned, drilled, tapped and plated to produce a finished hex nut/nut for air conditioning.
• the nut/nut is resistant to neutral salt spray for more than 1000 hours.
• the above cold heading is processed by 5 stations.
• the total amount of inevitable impurity elements in the alloy components in the above respective examples was less than 0.01%.

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