Preparation method of 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connecting piece

Abstract

The invention provides a preparation method of 4Cr5MoSiV1 die steel for producing a photovoltaic aluminum profile connecting piece. The preparation method comprises the following steps: heating a working platform of selective laser melting technical equipment; then a layer of smelting metal powder is evenly laid on the working platform; laser scans along a preset path in a staggered scanning mode and melts the smelted metal powder to form a solid layer; after each layer is smelted, a layer of smelted metal powder is laid again, and the process is repeated until a mold steel billet is formed; and then heat treatment and finish machining are conducted on the die steel billet till the 4Cr5MoS iV1 die steel is formed. According to the method, the 4Cr5MoS iV1 die steel is formed by using smelting metal powder with improved component proportion and selecting a selective laser melting technology, so that the yield strength, the tensile strength and the percentage elongation after fracture of the 4Cr5MoS iV1 die steel are enhanced, and the service life of the die steel is prolonged; and the surface problems of the extruded photovoltaic aluminum profile are reduced, and the one-time mold testing qualification rate and the yield of the photovoltaic aluminum profile before the mold is overhauled for the first time are improved.

Description

[Technical field]

[0001] The invention relates to the technical field of photovoltaic bracket manufacturing, and in particular to a method for preparing 4Cr5MoS iV1 die steel for producing photovoltaic aluminum profile connectors. [Background technology]

[0002] In the production and manufacturing of photovoltaic brackets, the raw materials are usually 6005 / 6063 / 6061 series aluminum alloys to form aluminum rods, which are then formed into aluminum profiles through extrusion molding, and finally aluminum alloy photovoltaic brackets are made using aluminum profiles. The mold used in the hot pressing process is made of 4Cr5MoS iV1 steel as the raw material. 4Cr5MoSiV1 steel is often used to produce hot working molds, especially aluminum extrusion molds, due to its excellent heat resistance and mechanical strength. Before the existing extrusion mold is used, it needs to be nitrided to form a hard nitride film on the surface, which is beneficial to improve the surface strength and corrosion resistance of the mold. Long-term production applications have found that even if the extrusion mold has been nitrided, the surface quality of the aluminum profile produced will deteriorate after a certain period of production, and the surface of the extrusion mold is prone to scratches. Therefore, the scratched extrusion mold surface needs to be maintained and surface treated in the later stage to extend its service life.

[0003] The existing 4Cr5MoS iV1 die steel manufacturing method is to melt and forge into 4Cr5MoS iV1 steel bars and then process them through precision CNC machine tools. The advantage is that it can mass-produce hot-working die steel required for general structural profiles. However, for some complex structures or multiple molds, or large aluminum profile extrusion production, there are often problems such as insufficient precision, easy mold damage, and certain production limits.

[0004] In view of this, the inventor of this case conducted in-depth research on the above-mentioned issues, which led to the emergence of this case. [Summary of the invention]

[0005] The present invention aims to solve the technical problems in the prior art that 4Cr5MoS iV1 die steel is easily scratched when preparing aluminum profiles and the production volume is limited, and provides a method for preparing 4Cr5MoS iV1 die steel for producing photovoltaic aluminum profile connectors.

[0006] The present invention is implemented as follows: A method for preparing 4Cr5MoS iV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0007] Step 1: Prepare smelted metal powder with a particle size range of 15-45 μm; vacuum dry the powder to remove moisture;

[0008] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 300W-400W, the scanning speed at 700mm / s-1200mm / s, and the point distance at 0.08mm-0.12mm;

[0009] Step 3: Heat the working platform of the selective laser melting technology equipment to 200-300°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled at 20μm-40μm; the laser scans and melts the molten metal powder along the preset path in an interlaced scanning mode to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and a new layer of molten metal powder will be spread, and the above process will be repeated until the mold billet is formed;

[0010] Step 4: Heat treatment of the mold steel billet; heating to 600-650℃, keeping warm for 2-4 hours, and then cooling with the furnace; quenching, quenching temperature 1020-1050℃, keeping warm for 30 minutes and then oil cooling; tempering, tempering temperature 550-600℃, tempering 2-3 times;

[0011] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0012] Furthermore, in step 2, the laser power is controlled at 350W, the scanning speed is controlled at 850mm / s, and the point pitch is controlled at 0.10mm; in step 3, the whole process is carried out in an inert gas environment, the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm; the working platform is heated to 250°C; the layer thickness is controlled at 30μm; in step 4, first heated to 620°C, kept warm for 3 hours, and then cooled with the furnace; quenching, quenching temperature 1035°C, kept warm for 30 minutes and then oil cooled; tempering, tempering temperature 580°C, tempering 2-3 times.

[0013] Furthermore, the smelted metal powder includes Fe: 89.4-92.03%, C: 0.32-0.45%, Si: 0.8-1.2%, Mn: 0.2-0.5%, Cr: 4.75-5.50%, Mo: 1.10-1.75%, and V: 0.8-1.2%.

[0014] Furthermore, the particle size of the smelted metal powder is 32 μm.

[0015] Furthermore, the smelted metal powder includes Fe: 90.94%, C: 0.3%, Si: 1.2%, Mn: 0.21%, Cr: 4.75%, Mo: 1.7%, and V: 0.9%.

[0016] Furthermore, the smelted metal powder includes Fe: 91.03%, C: 0.37%, Si: 0.95%, Mn: 0.35%, Cr: 5.0%, Mo: 1.5%, and V: 0.8%.

[0017] Furthermore, the smelted metal powder includes Fe: 90.84%, C: 0.41%, Si: 0.8%, Mn: 0.4%, Cr: 5.25%, Mo: 1.2%, and V: 1.1%.

[0018] Furthermore, the smelted metal powder includes Fe: 90.6%, C: 0.45%, Si: 1.0%, Mn: 0.25%, Cr: 5.1%, Mo: 1.75%, and V: 0.85%.

[0019] Furthermore, the smelted metal powder includes Fe: 90.78%, C: 0.4%, Si: 1.0%, Mn: 0.38%, Cr: 5.09%, Mo: 1.30%, and V: 1.05%.

[0020] The advantages of the present invention are: the preparation method of 4Cr5MoS iV1 mold steel for producing photovoltaic aluminum profile connectors uses improved smelting metal powder and selects selective laser melting technology to form 4Cr5MoS iV1 mold steel, which not only enhances the yield strength, tensile strength and elongation after fracture of the 4Cr5MoS iV1 mold steel, but also improves the service life of the mold steel; all aspects of the mold steel performance are enhanced, which also reduces the surface problems of the extruded photovoltaic aluminum profiles, reduces the head and tail of the material, and improves the one-time mold test pass rate and the photovoltaic aluminum profile output before the first mold maintenance.

Brief Description of the Drawings

[0021] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0022] Figure 1 It is a structural schematic diagram of the first fitting surface of the first mold in Example 1.

[0023] Figure 2 It is a structural schematic diagram of the aluminum rod entry surface of the first mold in Example 1.

[0024] Figure 3 It is a schematic structural diagram of the second fitting surface of the second mold in the first embodiment.

[0025] Figure 4 It is a schematic structural diagram of the aluminum profile output surface of the second mold in Example 1.

[0026] Figure 5 It is a schematic diagram of the structure of the aluminum profile in the second embodiment.

[0027] Figure 6 It is a schematic diagram of the connection structure between the aluminum profile and the guide rail in the second embodiment.

[0028] The first mold 1 , the second mold 2 , the aluminum rod entry surface 11 , the first fitting surface 12 , the input port 13 , the second fitting surface 21 , the aluminum profile output surface 22 , the output port 23 , the aluminum profile 3 , and the guide rail 4 . [Specific implementation method]

[0029] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] It should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing these embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. In addition, the terms "first", "second", etc., etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0031] Embodiment 1

[0032] This embodiment provides a method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors, comprising the following steps:

[0033] Step 1: Prepare the molten metal powder with a particle size range of 15-45μm to ensure uniform particle distribution; air flow screening or laser particle size analyzer is used to detect whether the powder particle size meets the requirements. The powder is vacuum dried to remove moisture and avoid oxidation problems during printing.

[0034] Step 2: Use selective laser melting technology equipment. The selective laser melting technology equipment adopts MT650 produced by AVIC Mate; calibrate the equipment parameters, control the laser power at 300W-400W, the scanning speed at 700mm / s-1200mm / s, and the point pitch at 0.08mm-0.12mm.

[0035] Step 3: Heat the working platform of the selective laser melting technology equipment to 200-300℃ to reduce the accumulation of thermal stress during the printing process and prevent the parts from warping or cracking; then evenly spread a layer of molten metal powder on the working platform with a layer thickness of 20μm-40μm; the laser uses an interlaced scanning mode to scan and melt the molten metal powder along a preset path to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and re-spread a layer of molten metal powder, and repeat the above process until the mold billet is formed.

[0036] Step 4: Heat treat the mold steel billet; heat to 600-650℃, keep warm for 2-4 hours, and then cool with the furnace; quench, quenching temperature 1020-1050℃, keep warm for 30 minutes and then oil cool; temper, tempering temperature 550-600℃, tempering 2-3 times.

[0037] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0038] The 4Cr5MoS iV1 mold steel preparation method of this embodiment, 4Cr5MoS iV1 mold steel is used to prepare photovoltaic aluminum profile connectors, uses improved smelting metal powder, and selects selective laser melting technology to form 4Cr5MoS iV1 mold steel, which not only enhances the yield strength, tensile strength and elongation after fracture of the 4Cr5MoS iV1 mold steel, but also improves the service life of the mold steel; all aspects of the mold steel performance are enhanced, which also reduces the surface problems of the extruded photovoltaic aluminum profiles, reduces the head and tail of the material, and improves the one-time mold trial pass rate and the photovoltaic aluminum profile output before the first mold maintenance.

[0039] In step 3 of this embodiment, the whole process is carried out in an inert gas environment, wherein the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100 ppm to avoid metal oxidation. The working platform is heated to 250° C.; the layer thickness is controlled at 30 μm.

[0040] In step 4 of this embodiment, first heat to 620°C, keep warm for 3 hours, and then cool with the furnace; quench, quenching temperature is 1035°C, keep warm for 30 minutes and then oil cool; temper, tempering temperature is 580°C, tempering 2-3 times.

[0041] In step 1 of this embodiment, according to GB / T1299-2014, the smelted metal powder in step 1 includes Fe: 89.4-92.03%, C: 0.32-0.45%, Si: 0.8-1.2%, Mn: 0.2-0.5%, Cr: 4.75-5.50%, Mo: 1.10-1.75%, V: 0.8-1.2%. The particle size of the smelted metal powder is preferably 32 μm.

[0042] The Fe element serves as a matrix for the smelted metal powder.

[0043] The C element is used to ensure the hardness of the steel after quenching and tempering, and at the same time make the steel have good thermal conductivity and higher impact toughness.

[0044] The Si element is used to increase the hardenability and tempering resistance of steel and improve the matrix strength; at the same time, it reduces the decarburization tendency of 4Cr5MoS iV1 mold steel at high temperatures and improves its high-temperature oxidation resistance; it can also hinder the diffusion of C in the Fe element, making it difficult for carbides to grow and improving the stability of tempering.

[0045] The Mn element is used to change the properties and shape of the oxides formed when the steel solidifies.

[0046] The Cr element has a high content in the molten metal powder and has high hardenability. When quenching, air cooling can obtain martensite structure. The Cr element can significantly improve the strength and wear resistance of steel, and at the same time improve its hardenability and thermal stability. After quenching, air cooling can obtain martensite structure. It can also combine with carbon to form carbides, such as (FeCr)3C, (FeCr)7C3 and other carbides, thereby improving the strength and wear resistance of steel. Cr can also form a passivation film on the surface of steel to effectively prevent corrosion.

[0047] Mo element is used to improve the hardenability and tempering resistance of steel and reduce or inhibit temper brittleness. Mo element can not only inhibit the temper brittleness of 4Cr5MoS iV1 die steel during tempering, but also improve the hardenability and tempering resistance stability of 4Cr5MoS iV1 die steel, and can form Mo2C type carbide with C.

[0048] The V element is used to improve the tempering stability and hot hardness of 4Cr5MoS iV1 die steel. At the same time, it can refine the grains to a certain extent and combine with C to form fine VC type carbides, which are stable and not easy to grow at high temperatures.

[0049] During the selective laser melting process, the adjustment of laser power, scanning speed and dot pitch will significantly affect the final quality of the mold steel. These parameters are directly related to the density, mechanical properties and surface quality of the finished product; therefore, these parameters must be carefully controlled and optimized to balance the printing accuracy, efficiency and quality.

[0050] In view of this, the 4Cr5MoS iV1 die steel preparation method for producing photovoltaic aluminum profile connectors was used to conduct multiple groups of tests. In step 1, the smelted steel billet metal powder includes Fe: 90.84%, C: 0.39%, Si: 0.99%, Mn: 0.32%, Cr: 5.04%, Mo: 1.49%, V: 0.94%, and the particle size of the smelted metal powder is 3.0 μm; in step 3, the working platform is heated to 250°C, and the thickness of the smelted metal powder layer is controlled at 30 μm; in step 4, the mold is heat treated; heated to 600°C, kept warm for 3 hours, and then cooled with the furnace; quenched at 1020°C, kept warm for 30 minutes and then oil cooled; tempered at 550°C, tempered 3 times; in step 2, each test group changes the parameters of laser power, scanning speed, and dot pitch for testing; finally, the molded 4Cr5MoS The porosity and surface roughness of iV1 mold steel were tested, and the results are as follows:

[0051] Table 1 Porosity and surface roughness parameters of 4Cr5MoS iV1 die steel in each test group

[0052]

[0053]

[0054] (Porosity is measured in accordance with GB / T 43101-2023; surface roughness is measured in accordance with GB / T 1031-2009)

[0055] According to Table 1, the effect of test group 7 is the best, and the 4Cr5MoSiV1 die steel has the lowest porosity and surface roughness. Therefore:

[0056] 1. The laser power is optimally controlled at 350W. Increasing the laser power helps to completely melt the powder and improve density and strength. However, too high a power may cause over-melting of the material, forming a rough surface or holes, or even deformation and cracking; reducing the laser power may lead to insufficient melting, increase porosity, and reduce the mechanical properties and density of the mold.

[0057] 2. The scanning speed is optimally controlled at 850mm / s. Increasing the scanning speed will improve the printing efficiency, but it is easy to cause incomplete melting, resulting in pores in the material, reducing density and strength; reducing the scanning speed will help improve the melting depth and interlayer bonding strength, but reducing the printing speed may lead to thermal stress accumulation and increase the risk of deformation.

[0058] 3. The optimal dot pitch is 0.10mm. Increasing the dot pitch will increase the printing speed, but may lead to poor interlayer bonding, pores and insufficient strength; decreasing the dot pitch will improve the interlayer bonding quality and surface finish, but will also reduce the printing speed and increase material consumption.

[0059] The beneficial effects of the 4Cr5MoS iV1 die steel preparation method for producing photovoltaic aluminum profile connectors using this embodiment are described below through several experimental groups. In step 2 of each experimental group, the laser power is controlled at 350W, the scanning speed is controlled at 850mm / s, and the point pitch is controlled at 0.10mm.

[0060] Experimental Group 1

[0061] A method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0062] Step 1: preparing smelting metal powder, the powder particle size range is 32μm; the powder is vacuum dried to remove moisture; the smelting metal powder includes Fe: 90.94%, C: 0.3%, Si: 1.2%, Mn: 0.21%, Cr: 4.75%, Mo: 1.7%, V: 0.9%.

[0063] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 350W, the scanning speed at 850mm / s, and the point pitch at 0.10mm.

[0064] Step 3: Heat the working platform of the selective laser melting technology equipment to 250°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled at 30μm; the laser uses a staggered scanning mode to scan and melt the molten metal powder along a preset path to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and re-spread a layer of molten metal powder, and repeat the above process until the mold billet is formed; the whole process is carried out in an inert gas environment, and the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm.

[0065] Step 4: Heat treat the mold steel billet; heat to 620℃, keep warm for 3 hours, and then cool with the furnace; quench, quenching temperature 1035℃, keep warm for 30 minutes and then oil cool; temper, tempering temperature 580℃, tempering 2-3 times.

[0066] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0067] Experimental Group 2

[0068] A method for preparing 4Cr5MoS iV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0069] Step 1: prepare smelting metal powder, the powder particle size range is 32μm; the powder is vacuum dried to remove moisture; the smelting metal powder includes Fe: 91.03%, C: 0.37%, Si: 0.95%, Mn: 0.35%, Cr: 5.0%, Mo: 1.5%, V: 0.8%.

[0070] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 350W, the scanning speed at 850mm / s, and the point pitch at 0.10mm.

[0071] Step 3: Heat the working platform of the selective laser melting technology equipment to 250°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled at 30μm; the laser uses a staggered scanning mode to scan and melt the molten metal powder along a preset path to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and re-spread a layer of molten metal powder, and repeat the above process until the mold billet is formed; the whole process is carried out in an inert gas environment, and the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm.

[0072] Step 4: Heat treat the mold steel billet; heat to 620℃, keep warm for 3 hours, and then cool with the furnace; quench, quenching temperature 1035℃, keep warm for 30 minutes and then oil cool; temper, tempering temperature 580℃, tempering 2-3 times.

[0073] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0074] Experimental Group 3

[0075] A method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0076] Step 1: preparing smelting metal powder, the powder particle size range is 32μm; the powder is vacuum dried to remove moisture; the smelting metal powder includes Fe: 90.84%, C: 0.41%, Si: 0.8%, Mn: 0.4%, Cr: 5.25%, Mo: 1.2%, V: 1.1%.

[0077] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 350W, the scanning speed at 850mm / s, and the point pitch at 0.10mm.

[0078] Step 3: Heat the working platform of the selective laser melting technology equipment to 250°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled at 30μm; the laser uses a staggered scanning mode to scan and melt the molten metal powder along a preset path to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and re-spread a layer of molten metal powder, and repeat the above process until the mold billet is formed; the whole process is carried out in an inert gas environment, and the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm.

[0079] Step 4: Heat treat the mold steel billet; heat to 620℃, keep warm for 3 hours, and then cool with the furnace; quench, quenching temperature 1035℃, keep warm for 30 minutes and then oil cool; temper, tempering temperature 580℃, tempering 2-3 times.

[0080] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0081] Experimental Group 4

[0082] A method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0083] Step 1: preparing smelting metal powder, the powder particle size range is 32μm; the powder is vacuum dried to remove moisture; the smelting metal powder includes Fe: 90.6%, C: 0.45%, Si: 1.0%, Mn: 0.25%, Cr: 5.1%, Mo: 1.75%, V: 0.85%.

[0084] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 350W, the scanning speed at 850mm / s, and the point pitch at 0.10mm;

[0085] Step 3: Heat the working platform of the selective laser melting technology equipment to 250°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled to be 30μm; the laser scans and melts the molten metal powder along a preset path in an interlaced scanning mode to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and a new layer of molten metal powder will be spread, and the above process will be repeated until the mold billet is formed; the whole process is carried out in an inert gas environment, and the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm;

[0086] Step 4: Heat treatment of the mold steel billet; heating to 620°C, keeping warm for 3 hours, and then cooling with the furnace; quenching, quenching temperature 1035°C, keeping warm for 30 minutes and then oil cooling; tempering, tempering temperature 580°C, tempering 2-3 times;

[0087] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0088] Experimental Group 5

[0089] A method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors comprises the following steps:

[0090] Step 1: preparing smelting metal powder, the powder particle size range is 32μm; the powder is vacuum dried to remove moisture; the smelting metal powder includes Fe: 90.78%, C: 0.4%, Si: 1.0%, Mn: 0.38%, Cr: 5.09%, Mo: 1.30%, V: 1.05%.

[0091] Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 350W, the scanning speed at 850mm / s, and the point pitch at 0.10mm;

[0092] Step 3: Heat the working platform of the selective laser melting technology equipment to 250°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled to be 30μm; the laser scans and melts the molten metal powder along a preset path in an interlaced scanning mode to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and a new layer of molten metal powder will be spread, and the above process will be repeated until the mold billet is formed; the whole process is carried out in an inert gas environment, and the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100ppm;

[0093] Step 4: Heat treatment of the mold steel billet; heating to 620°C, keeping warm for 3 hours, and then cooling with the furnace; quenching, quenching temperature 1035°C, keeping warm for 30 minutes and then oil cooling; tempering, tempering temperature 580°C, tempering 2-3 times;

[0094] Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoS iV1 mold steel is formed.

[0095] The properties of 4Cr5MoS iV1 die steels obtained in experimental groups 1-5 were tested, including yield strength, tensile strength, elongation after fracture, elastic modulus, Poisson's ratio, density, thermal expansion coefficient, and thermal conductivity. (The yield strength is used to indicate the maximum stress that 4Cr5MoS iV1 mold steel can withstand before yielding. The tensile strength is used to indicate the maximum tensile stress that 4Cr5MoS iV1 mold steel can withstand. The elastic modulus is the standard value of 4Cr5MoS iV1 mold steel, which is used to describe the stiffness of 4Cr5MoS iV1 mold steel in the elastic deformation stage. The Poisson's ratio is used to describe the degree of lateral deformation of 4Cr5MoS iV1 mold steel when it is axially compressed or tensile. The thermal expansion coefficient is used for thermal stress analysis, especially in high-temperature use occasions of 4Cr5MoS iV1 mold steel. The thermal conductivity is used to simulate the heat dissipation performance of 4Cr5MoS iV1 mold steel. In general, the various parameters of traditional 4Cr5MoS iV1 mold steel must meet the following requirements: yield strength: ≥1200MPa; tensile strength: ≥1500MPa; elongation after fracture: ≥7%; elastic modulus: ≥205GPa; Poisson's ratio: ≥0.25; density: ≥7.50g / cm 3 ; Thermal expansion coefficient: ≥9×10 -6 K-1 (in the range of room temperature to 205℃); thermal conductivity: ≥22W·m-1·K-1. )

[0096] Table 2 Relevant performance parameters of 4Cr5MoS iV1 die steel obtained in experimental groups 1-5

[0097] Experimental Group 1 Experimental Group 2 Experimental Group 3 Experimental Group 4 Experimental Group 5 Yield strength / MPa 1620 1608 1650 1630 1670 Tensile strength / MPa 1830 1820 1805 1845 1850 Elongation after break / % 9 9 9 8 10 Elastic modulus E / GPa 208 212 210 209 213 Poisson's ratio ν 0.280 0.295 0.275 0.285 0.3 Densityρ / g / cm3 7.79 7.8 7.79 7.78 7.81 Thermal expansion coefficient α / K-1 <![CDATA[10.9×10 -6 ]]> <![CDATA[11.1×10 -6 ]]> <![CDATA[10.5×10 -6 ]]> <![CDATA[11.8×0 -6 ]]> <![CDATA[11.0×10 -6 ]]> Thermal conductivity k / W·m-1·K-1 26 27 25 28 28

[0098] According to Table 2, the 4Cr5MoS iV1 die steels prepared in Experimental Groups 1 to 5 have higher yield strength, tensile strength, elongation after fracture, etc. than conventional die steels. Preferably, the 4Cr5MoS iV1 die steel prepared in Experimental Group 5 has the best performance.

[0099] Embodiment 2

[0100] This embodiment provides a 4Cr5MoS iV1 die steel, and its substantial structure is shown in the attached Figure 1-4As shown, it includes a first mold 1 and a second mold 2; the first mold 1 includes an aluminum rod entry surface 11 and a first fitting surface 12, and the second mold 2 includes a second fitting surface 21 and an aluminum profile output surface 22. A plurality of input ports 13 are formed on the aluminum rod entry surface 11, and two output ports 23 are formed on the aluminum profile output surface 22. The main cylinder of the 1350T extruder is fixed, and the second mold 2 with two output ports 23 is designed, and the discharge speed is halved, but the extrusion ratio becomes smaller and the pressure is reduced from a single port to a double port, and the main cylinder speed is increased, thereby increasing the discharge speed. When the 4Cr5MoSiV1 mold steel is working, the first fitting surface 12 of the first mold 1 and the second fitting surface 21 of the second mold 2 are engaged, and the 6005 aluminum rod melts from the aluminum rod entry surface 11 and enters the mold steel, and then two aluminum profiles are formed from the aluminum profile output surface 22.

[0101] In this embodiment, five types of 4Cr5MoS iV1 die steels prepared in experimental groups 1-5 in embodiment 1 are used to produce aluminum profile 3. The substantial structure of aluminum profile 3 is shown in the attached figure. Figure 5-6 As shown, the aluminum profile 3 is a guide rail connector of the photovoltaic support, which is used to connect the guide rail 4 of the photovoltaic support.

[0102] During extrusion molding, experimental groups 1-5 all used 6005 aluminum rods to extrude aluminum profile 3. The rod temperature of the 6005 aluminum rod was controlled at 420-430°C, the diameter of the 6005 aluminum rod was 135mm, and the weight of a 1-meter-long 6005 aluminum rod was 38.77kg. The machine used was 1350T, the number of discharge holes was 2 holes, the discharge speed was 14.0m / min, the main cylinder speed was 3.1mm / s, the extrusion ratio was 53.0, the diameter of the extrusion barrel was 140mm, the mold temperature of the 4Cr5MoS iV1 mold steel was controlled at 450-460°C, and the quenching temperature was controlled at 500-520°C.

[0103] Table 3 Data of aluminum profiles extruded from 4Cr5MoS iV1 die steel obtained from experimental groups 1-5

[0104]

[0105]

[0106] The actual mold trial pass rate of traditional mold steel can reach 60%, which is very good. The maximum tonnage of aluminum profiles that can be produced before the first mold repair is about 5-6 tons, and the maximum tonnage of aluminum profiles produced before scrapping is about 14-16 tons.

[0107] According to Table 3, we can see that:

[0108] 1. The one-time mold test pass rate of the 4Cr5MoS iV1 mold steel of the experimental groups 1-5 is 65-72%, and the maximum tonnage of aluminum profiles that can be produced before the first mold repair is in the range of 9.5-10.3 tons. The output of photovoltaic aluminum profiles before the first overhaul is greatly improved, which shows that the surface of the 4Cr5MoSiV1 mold steel of the present invention is not easy to be scratched. The maximum tonnage of aluminum profiles produced before scrapping is in the range of 18.5-19.5 tons, which is equivalent to the service life of the 4Cr5MoS iV1 mold steel of the present invention is significantly improved.

[0109] 2. The maximum extrusion speed of the 4Cr5MoSiV1 die steel in the experimental groups 1-5 can reach the range of 12.7m / min-14.5m / min, which shows that the die steel with improved composition has excellent surface properties and can improve the production efficiency of extrusion molding.

[0110] 3. The produced aluminum profile 3 was tested and it was found that the surface problems of the extruded aluminum profile 3 were reduced and the head and tail of the material were reduced, indicating that the quality of extrusion molding was improved.

[0111] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Any equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors, characterized in that: The steps include: Step 1: Prepare smelted metal powder with a particle size range of 15-45 μm; vacuum dry the powder to remove moisture; Step 2: Use the selective laser melting technology equipment to calibrate the equipment parameters, control the laser power at 300W-400W, the scanning speed at 700mm / s-1200mm / s, and the point distance at 0.08mm-0.12mm; Step 3: Heat the working platform of the selective laser melting technology equipment to 200-300°C; then evenly spread a layer of molten metal powder on the working platform, and the layer thickness is controlled at 20μm-40μm; the laser scans and melts the molten metal powder along the preset path in an interlaced scanning mode to form a solid layer; after each layer is melted, the working platform will drop a layer thickness and a new layer of molten metal powder will be spread, and the above process will be repeated until the mold billet is formed; Step 4: Heat treatment of the mold steel billet; heating to 600-650℃, keeping warm for 2-4 hours, and then cooling with the furnace; quenching, quenching temperature 1020-1050℃, keeping warm for 30 minutes and then oil cooling; tempering, tempering temperature 550-600℃, tempering 2-3 times; Step 5: Finish the mold steel billet, polish or surface coat it as required, until the 4Cr5MoSiV1 mold steel is formed.

2. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 1, characterized in that: In step 2, the laser power is controlled at 350 W, the scanning speed is controlled at 850 mm / s, and the dot pitch is controlled at 0.10 mm; In step 3, the whole process is carried out in an inert gas environment, wherein the inert gas includes 20% nitrogen and 80% argon, and the oxygen content is controlled below 100 ppm; the working platform is heated to 250° C.; the layer thickness is controlled at 30 μm; In step 4, first heat to 620°C, keep warm for 3 hours, and then cool with the furnace; quench, quenching temperature is 1035°C, keep warm for 30 minutes and then oil cool; temper, tempering temperature is 580°C, tempering 2-3 times.

3. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to any one of claims 1 or 2, characterized in that: The smelted metal powder comprises Fe: 89.4-92.03% C：0.32-0.45％ Si: 0.8-1.2% Mn: 0.2-0.5% Cr：4.75-5.50％ Mo: 1.10-1.75% V：0.8-1.2％。 4. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The particle size of the smelted metal powder is 32 μm.

5. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The smelted metal powder comprises Fe: 90.94% C：0.3％ Si: 1.2% Mn: 0.21% Cr：4.75％ Mo: 1.7% V：0.9％。 6. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The smelted metal powder comprises Fe: 91.03% C：0.37％ Si: 0.95% Mn: 0.35% Cr：5.0％ Mo: 1.5% V：0.8％。 7. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The smelted metal powder comprises Fe: 90.84% C：0.41％ Si: 0.8% Mn: 0.4% Cr：5.25％ Mo: 1.2% V：1.1％。 8. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The smelted metal powder comprises Fe: 90.6% C：0.45％ Si: 1.0% Mn: 0.25% Cr：5.1％ Mo: 1.75% V：0.85％。 9. The method for preparing 4Cr5MoSiV1 die steel for producing photovoltaic aluminum profile connectors according to claim 3, characterized in that: The smelted metal powder comprises Fe: 90.78% C：0.4％ Si: 1.0% Mn: 0.38% Cr：5.09％ Mo: 1.30% V：1.05％。

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