Processing method for producing wood grain gold with controllable texture by molding

Abstract

The present invention belongs to the field of metallurgy technology, specifically to a process method for producing wood grain gold with controllable texture by die pressing, wherein various metal sheets are pre-processed into metal profiles of various shapes by die pressing, and after stacking several layers, they are placed in a sintering device and pressed and fixed to obtain a wood grain gold raw material with a specific pattern. The method can produce a pattern without a large deformation after sintering, or even without the need for deformation processing, and the pattern can grow according to requirements, thus realizing a truly controllable pattern.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a process for producing wood-grained metal with controllable texture by molding. Background Art

[0002] The wood grain gold craft is a traditional craft that has been passed down for thousands of years. It originated from my country's piled-up cloud-carved lacquerware and was later passed on to Japan. Japanese gold craftsmen used the difference in the colors of different metals to stack various metals and heat and forge them to form a composite metal whole. The wood grain gold craft has been passed down for hundreds of years. After continuous improvement, it has formed a modern wood grain gold craft production system, which is currently widely used in the production of jewelry and handicrafts. Due to the influence of many factors such as the selection of metal materials, metal surface treatment, sintering pressure control, sintering temperature control, sintering atmosphere control and material surface pattern treatment in the current wood grain gold production process, coupled with relatively large processing losses, the material yield rate is low, especially for some non-ferrous metal alloys. Due to the uneven melting point, high hardness and small processing deformation, it is easy for each metal layer to tear during the later pattern production. This makes it difficult for some non-ferrous metal materials to be mass-produced in the market.

[0003] The method for making wood grain gold disclosed in the patent document with publication number 102962640A is to quickly wipe the cleaned wood grain metal raw materials, and alternately stack them on the mold. The mold is connected together by two pieces of high-temperature hot working die steel through a screw set; the fastened mold is placed in a stainless steel foil box, and charcoal particles are poured into the stainless steel foil box at the same time, and the sealed stainless steel foil box is placed in an electric kiln, and the constant temperature is maintained for 6-10 hours; the electric kiln is turned off, the stainless steel foil box is taken out, and it is naturally cooled to room temperature to obtain a rough wood grain metal blank. This method has high requirements on the surface finish of the metal material, the welding size is limited by the mold, the sintered material volume is small, and the electric kiln sintering time is long, and the production efficiency is low. In some cases, some side effects will occur, the parent metal grains may grow excessively, and the metal ductility is limited.

[0004] The method for making wood grain metal disclosed in the patent document with publication number 108085533A uses two steel plates to clamp the superimposed copper composite, brass composite and cupronickel composite, and fix the two steel plates with screws. After clamping and fixing, the steel plates, copper composite, brass composite and cupronickel composite are placed in an electric furnace for heating and welding. After heating, they are taken out and left to cool down to form a rough wood grain metal blank. In this process, the superimposed metal raw materials are fixed by steel plates. As the sintering temperature increases, the iron wire and steel plates used expand due to heat, and the clamping force on the metal is instantly reduced, and the pressure cannot be effectively maintained continuously, which causes the gaps between the metal raw materials to become larger and form diffusion cavities.

[0005] The method for making composite non-ferrous metal wood grain gold disclosed in the patent document with publication number CN110757108A controls the sintering temperature at 930°C-960°C in a specific sintering device, heats for 10min-180min, applies a pressure of 10MPa-50MPa between metal sheets, and obtains a wood grain gold raw material. The wood grain gold raw material is then heated to a recrystallization temperature, taken out and forged several times while hot, and the whole is rolled until it is flat. The obtained wood grain gold sheet is forged or cut into wood grain gold rods. This method uses conventional means such as forging, cutting, drilling, twisting and rolling to make various patterns appear on metal materials. This method is suitable for some non-ferrous metal materials with good ductility and can be processed with a large deformation amount. However, for non-ferrous metals with poor ductility and cannot be processed with a large deformation amount, conventional forging, cutting, drilling, twisting, rolling and other technical means for surface pattern processing can only produce a single parallel texture; in particular, the wood-grained gold material obtained by sintering non-ferrous metals with good ductility and non-ferrous metals with poor ductility together has a large difference in ductility, and is prone to tearing and breaking during secondary pattern processing, thereby reducing the yield rate. Summary of the invention

[0006] In view of the problems existing in the existing wood grain gold process, the present invention provides a process method for producing wood grain gold with controllable texture by molding.

[0007] The process for producing wood grain gold with controllable texture by molding of the present invention is characterized in that the method comprises the following steps:

[0008] Step 1, material preparation: according to the metal raw materials including copper-based materials, silver-based materials or gold-based materials, according to the requirements of the post-production surface pattern, select specific metal raw materials and cut them into metal sheets of the same shape and size and thickness of 0.5mm-2mm, anneal the metal sheets to remove metal oxides, and polish and clean them;

[0009] Step 2, compression molding: various metal sheets are pre-processed into metal profiles of various shapes by compression molding, and after stacking several layers, they are placed in a sintering device and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 10MPa-100MPa; the sintering bin of the sintering device is filled with protective gas, and the heating element of the sintering device is started. The heating temperature is controlled to be 760℃-960℃, and the heating is performed for 10min-180min to obtain a specific pattern wood grain gold raw material with a thickness of 5mm-8mm.

[0010] The process for producing wood grain gold with controllable texture by molding also includes:

[0011] Step 3, secondary compression molding: according to the requirements of the surface pattern of the later production, the wood grain gold sheet is cleaned by degreasing and surface oxide treatment, and a combination of several wood grain gold raw materials or a combination of wood grain gold raw materials and metal profiles is selected, and several layers are stacked and placed in the sintering equipment and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 10MPa-100MPa; the sintering bin of the sintering equipment is filled with protective gas, and the heating element of the sintering equipment is started. The heating temperature is controlled to be 760℃-960℃, and the heating is 10min-180min to obtain a wood grain gold metal block, which is heated to the recrystallization temperature, that is, 80% of the solidus temperature of the lowest melting point metal in the metal raw material, and the compression treatment is performed again, so that the wood grain gold metal block obtains the ideal pattern texture or ideal shape, and then uses CNC numerical control composite cutting. In step 3, controlling the wood grain gold metal block to heat to the recrystallization temperature can avoid excessive crystal production and further avoid subsequent process defects.

[0012] The metal sheets described in step 1 are evenly polished with 400, 800, 1200 and 2000 water sandpapers respectively, and the metal surface roughness reaches Ra>2.5μm, so as to eliminate the oxide layer, scratches and burrs on the metal sheets, which is conducive to the close bonding between the bonding surfaces.

[0013] The matching of the metal sheets described in step 2 and the sintering temperature and pressure parameters of the selected metal sheets are important factors for the quality of the wood grain gold profile. The metal profiles after molding present different shapes, so the contact area between the metal profiles is different. Therefore, it is necessary to further adjust the pressure between the metal sheets and the sintering temperature to obtain a wood grain gold profile with controllable quality. See the following table for details:

[0014]

[0015]

[0016] The metal raw materials involved in step 2 are more abundant. New sintering temperature and pressure values ​​are selected for metal profiles molded into specific shapes, so that the wood grain gold raw materials after sintering have fewer defects. The reason is that the parameter selection of the diffusion sintering process mainly determines the degree of atomic diffusion and interface reaction, and also affects the creep of the connected metal. The interface products and interface structures formed are different for different sintering times. During diffusion sintering, the higher the degree of uniformity of the joint components required, the sintering time will increase at a square rate. In the actual diffusion sintering process, the time ranges from a few minutes to a few hours, or even tens of hours. However, from the perspective of improving productivity, the shorter the connection time, the better. If the connection time is shortened, the temperature and pressure must be increased accordingly. For the instantaneous liquid phase diffusion connection temperature, it is often selected near the lowest temperature at which the liquid phase can be generated. Too high a temperature will cause excessive dissolution of the parent material, forming more intermediate alloys, and affecting the overall coloring effect in the later production process. The process method for producing wood grain gold with controllable texture by mold pressing, according to the processing needs, selects the following methods to perform surface pattern treatment on the wood grain gold metal block:

[0017] Heating treatment: After degreasing and cleaning the surface of the wood grain gold metal block, put it into the oven for heating, the heating temperature is: 150°-330°, so that the surface of the wood grain gold metal block shows obvious color difference;

[0018] Corrosion treatment: Select different concentrations of hydrochloric acid, nitric acid, ferric chloride, and aqua regia to corrode the surface of the material, so that the surface of the wood grain gold metal block forms uneven texture;

[0019] Sandblasting: Select a material with appropriate hardness to sandblast the surface to make the wood grain and gold metal block pattern appear;

[0020] Chemical coloring treatment: Put the wood grain gold metal block into a properly prepared potion to show different color differences on the surface, making the pattern of the wood grain gold metal block more obvious.

[0021] The process method of the wood grain gold of the present invention has the beneficial effect that the method can produce patterns without large deformation after sintering, and even without deformation processing, and the patterns can grow according to requirements, realizing truly controllable patterns. Sheets, plates, and tubes with certain textures can be directly molded according to actual jewelry production needs. It effectively solves the problem that the original material without patterns can only be sintered, and patterns are not produced without large deformation, thereby avoiding the generation of a large amount of waste raw materials and post-processing defects. DETAILED DESCRIPTION

[0022] Embodiment 1: White 14K gold, yellow 14K gold, and red 14K gold are selected and cut into metal sheets of the same shape and size and 0.5 mm in thickness. The metal sheets are annealed to remove metal oxides, and are polished and cleaned; brass and white copper metal sheets are pre-processed into metal profiles of a specific shape by molding, and after tightly stacking 20 layers, they are placed in a sintering device and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 80 MPa; the sintering bin of the sintering device is filled with protective gas, the heating element of the sintering device is started, the heating temperature is controlled to be 800° C., and the heating is performed for 180 minutes to obtain a specific pattern wood grain gold raw material with a thickness of 8 mm.

[0023] Embodiment 2: Brass and cupronickel are selected and cut into metal sheets of the same shape and size and 2 mm in thickness. The metal sheets are annealed to remove metal oxides, and then polished and cleaned. The brass and cupronickel metal sheets are pre-processed into curved wavy metal profiles by molding, tightly stacked and placed in a sintering device and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 80 MPa. The sintering bin of the sintering device is filled with protective gas, and the heating element of the sintering device is started. The heating temperature is controlled to be 920°C and heated for 180 minutes to obtain a specific pattern wood grain gold raw material with a thickness of 3.5 mm. The pattern is presented as a plurality of small concentric circular rods, which are then molded twice to become square rods. The pattern can be seen from multiple directions after turning and milling.

[0024] The advantages of the metal wood grain gold profile or wood grain gold metal block produced in the above embodiment are good quality, clear and controllable patterns, and short sintering time. However, the type of metal raw materials, sintering temperature and sintering pressure selected in the above embodiment are not the only options of the present invention. As long as the technical contents disclosed in the invention content are adopted, they should fall within the protection scope of the present invention.

Claims

1. A process for producing wood grain gold with controllable texture by molding, characterized in that The method comprises the following steps: Step 1), material preparation: according to the metal raw materials including copper-based materials, silver-based materials or gold-based materials, according to the requirements of the post-production surface pattern, select specific metal raw materials and cut them into metal sheets of the same shape and size and thickness of 0.5mm-2mm, anneal the metal sheets to remove metal oxides, and polish and clean them; Step 2), compression molding: various metal sheets are pre-processed into metal profiles of various shapes by compression molding, and after stacking several layers, they are placed in a sintering device and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 10MPa-100MPa; the sintering bin of the sintering device is filled with protective gas, and the heating element of the sintering device is started. The heating temperature is controlled to be 760℃-960℃, and the heating is performed for 10min-180min to obtain a specific pattern wood grain gold raw material with a thickness of 5mm~8mm; Step 3), secondary compression molding: according to the surface pattern requirements of the later production, the wood grain gold sheet is cleaned by degreasing and surface oxide treatment, and a combination of several wood grain gold raw materials, or a combination of wood grain gold raw materials and metal profiles is selected, and several layers are stacked and placed in a sintering device and pressed and fixed. When pressing, the pressure between the metal sheets needs to be controlled to be 10MPa-100MPa; the sintering bin of the sintering device is filled with protective gas, and the heating element of the sintering device is started. The heating temperature is controlled to be 760℃-960℃, and the heating is performed for 10min-180min to obtain a wood grain gold metal block. The wood grain gold metal block is heated to the recrystallization temperature, that is, 80% of the solidus temperature of the lowest melting point metal in the metal raw material, and the compression treatment is performed again to make the wood grain gold metal block obtain an ideal pattern texture or an ideal shape, and then CNC numerical control composite cutting is used.

2. The process for producing wood grain gold with controllable texture by molding as claimed in claim 1, characterized in that The metal sheets in step 1) are evenly polished with No. 400, No. 800, No. 1200 and No. 2000 water sandpapers respectively, and the metal surface roughness reaches Ra>2.5μm.

3. The process for producing wood grain gold with controllable texture by molding as claimed in claim 1, characterized in that The combination of the metal sheets in step 2) and the sintering temperature and pressure parameters of the selected metal sheets are shown in the following table: 。

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