Preparation process and application of a splitter cone

Abstract

The present invention relates to the field of plastic material forming, and more specifically, to a preparation process and application of a diverter cone. The steps are as follows: S1: design; S2: forging; S3: primary processing; S4: heating in a vacuum heating furnace, taking out and cooling, and then tempering in a tempering furnace; S5: secondary processing; S6: nitriding and oxidation; S7: vapor deposition; step S4 specifically comprises heating in a heating furnace, taking out and cooling to 75-110°C in air at 25°C, and then tempering. Using the diverter cone provided by the present invention in the die-casting process of aluminum products can make the molten metal flow evenly into the mold cavity. The diverter cone can withstand multiple die-casting operations, is erosion-resistant, and is not prone to cracking.

Description

Technical Field

[0001] The present invention relates to the field of plastic material molding, and more particularly to a preparation process of a diverter cone and application thereof. Background Art

[0002] During the die-casting process, after the aluminum liquid is injected into the mold, the first thing it contacts is the diverter cone, which guides the aluminum liquid into the mold cavity, thereby regulating the flow direction of the liquid.

[0003] Patent number CN104942263B provides a split cone for die-casting molds. This split cone structure extends the cone's service life by replacing the cone head. Patent number CN110230020A provides a split cone surface treatment method. Tungsten carbide powder is sprayed onto the cone surface at supersonic speed, resulting in a coating with a porosity of 2.8% while also improving the bonding strength of the tungsten carbide powder to the cone surface.

[0004] Existing technologies mostly improve the diverter cone from two aspects: structure or surface treatment. However, structural improvements rarely achieve improvements in its wear resistance, impact resistance, high temperature resistance and other properties. It is also difficult to improve the diverter cone through surface treatment while ensuring that the raw materials have good comprehensive properties. For example, when using tungsten carbide powder to treat the surface of the diverter cone, although its bonding strength is improved, the porosity of the tungsten carbide coating is greatly increased to less than 1%, which reduces the density of the coating. Summary of the Invention

[0005] In order to solve the above problems, the first aspect of the present invention provides a process for preparing a splitter cone, comprising the following steps:

[0006] S1: Design; S2: Forging; S3: Primary processing; S4: Heating in a vacuum heating furnace, taking out and cooling, and tempering in a tempering furnace; S5: Secondary processing; S6: Nitriding, oxidation; S7: Vapor deposition;

[0007] In step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 750-800°C at a heating rate of 1-2°C, keeping the temperature for 160-190 minutes, cooling to 710-740°C at a cooling rate of 2-3°C / min, and keeping the temperature for 10-20 minutes; the secondary heating is specifically heating to 970-1000°C at a heating rate of 1-2°C, keeping the temperature for 70-90 minutes, and cooling to 140-180°C at a cooling rate of 9-13°C / min.

[0008] Step S4 specifically comprises heating in a heating furnace, taking out and cooling to 75-110°C in air at 25°C, and then tempering;

[0009] The tempering treatment includes primary tempering, secondary tempering and tertiary tempering. The primary tempering is specifically tempering and keeping warm at 490-530℃ for 5.2-7.5h, taking out the tempering furnace and cooling to 65-90℃ in 25℃ air; the secondary tempering is specifically tempering and keeping warm at 440-480℃ for 5.2-6h, taking out the tempering furnace and cooling to 40-60℃ in 25℃ air; the tertiary tempering is specifically tempering and keeping warm at 540-560℃ for 5.2-7.5h, taking out the tempering furnace and cooling to 25℃ in air.

[0010] During the pouring process, as the molten metal flows through the diverter cone, it carries with it some slag. This slag reacts chemically with the surface of the diverter cone, causing cracks to form on the surface. To mitigate this problem, the applicant discovered that inserting a cooling phase between two heating phases, and adjusting the temperature and duration of three tempering phases, significantly reduced the probability of cracks in the diverter cone and unexpectedly improved its wear resistance. By controlling the heating and tempering conditions described above, the process of converting the ε-carbide precipitated during the decomposition of martensite into cementite in the diverter cone material is affected, improving the structure formed by the spheroidization and recrystallization of the cementite, thereby enhancing the performance of the diverter cone.

[0011] Preferably, step S2: forging is specifically adding the diverter cone material body into the hot forging machine saw for forging; step S3: primary processing is specifically sending the forged material obtained in S2 into a lathe for processing; step S5: finishing is specifically sending the processed part obtained in S4 into a CNC machine tool for further processing; step S6: nitriding and oxidation is specifically sending the workpiece obtained in S5 into a nitriding furnace for gas nitrogen oxidation.

[0012] Further preferably, the diverter cone material includes but is not limited to HPM1 material, H13 material, SUJ2 bearing steel, and SKD61 hot working die steel.

[0013] As a preferred technical solution of the present invention, the step S7 is to perform pretreatment before vapor deposition.

[0014] As a preferred technical solution of the present invention, the pretreatment is specifically carried out through a pulsed ion nitriding furnace.

[0015] As a preferred technical solution of the present invention, during the pretreatment, the nitriding temperature is 480-520° C. and the heat preservation time is 1.5-3 hours.

[0016] As a preferred technical solution of the present invention, during the pretreatment, the internal pressure of the pulse ion nitriding furnace is 190-220Pa.

[0017] Vapor deposition uses an electron beam to evaporate the material. In the present invention, the diverter cone that has been heated and tempered under the specific conditions of step S4 is affected by its structure. During the vapor deposition process, the evaporation rate is uneven, which causes the problem of poor deposition effect of the material on the diverter cone surface to be significantly amplified, thereby reducing the quality of the diverter cone. In order to overcome the above-mentioned technical resistance, the applicant performs specific pretreatment on the workpiece before vapor deposition, and treats it in a pulsed ion nitriding furnace with a nitriding temperature of 480-520°C and a heat preservation time of 1.5-3h. The internal pressure of the pulsed ion nitriding furnace is 190-220Pa, so that when the coating material is deposited, not only does the deposition effect not deteriorate, but it is improved, thereby improving the corrosion resistance of the diverter cone and the wear resistance. This may be because a unique transition layer is formed on the surface of the diverter cone, which is affected by the adsorption effect of the particles during vapor deposition, thereby improving the deposition, and at the same time improving the contact with the evaporated plasma, thereby improving the coating performance.

[0018] As a preferred technical solution of the present invention, in step S7, the vapor deposition is specifically performed by depositing the coating material through a Balzers coating machine.

[0019] As a preferred technical solution of the present invention, the coating material includes a tungsten carbide composite, a chromium nitride / diamond composite and a chromium nitride aluminum composite.

[0020] As a preferred technical solution of the present invention, the hardness of the tungsten carbide composite is 1000-2000 and the friction coefficient is 0.1-0.3.

[0021] Preferably, the friction coefficient of the chromium nitride / diamond composite is 0.1-0.3, and the friction coefficient of the chromium nitride aluminum composite is ≤0.35.

[0022] During the die-casting process, the diverter cone is subjected to the instantaneous impact of the high temperature of the molten metal. The temperature of the diverter cone surface rises, and a temperature difference is generated between the surface and the interior of the diverter cone, which causes the diverter cone to have considerable internal stress, thereby causing damage to the diverter cone and shortening its life. Through extensive experiments, the applicant found that using specific types of coating materials on the diverter cone surface, including a tungsten carbide composite with a hardness of 1000-2000 and a friction coefficient of 0.1-0.3, a chromium nitride / diamond composite with a friction coefficient of 0.1-0.3, and a chromium aluminum nitride composite with a friction coefficient of ≤0.35, can extend the service life of the diverter cone and improve the bonding strength of the coating material on the diverter cone surface, making the diverter cone less prone to damage during long-term die-casting operations. After the materials with different friction coefficients are combined, the adhesion between the materials changes. During the vapor deposition process, the deposition rate of the different coating materials is affected, thereby affecting the structure of the final composite coating. At the same time, the particles produced by tungsten carbide, chromium nitride, and chromium aluminum nitride work synergistically to improve the density of the coating, thereby improving the bonding strength. The above-mentioned effects are particularly significant when the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium aluminum nitride composite is (7-13):(1-2):(0.7-1.5).

[0023] As a preferred technical solution of the present invention, in the coating material, the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium nitride aluminum composite is (7-13): (1-2): (0.7-1.5).

[0024] A second aspect of the present invention provides an application of a process for preparing a diverter cone in the field of plastic material molding.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Inserting a cooling stage between the two heating stages, and the temperature and time of the three temperings greatly reduce the probability of cracks in the diverter cone, and unexpectedly improve the wear resistance of the diverter cone; the workpiece is subjected to specific pretreatment before vapor deposition, and is treated in a pulsed ion nitriding furnace with a nitriding temperature of 480-520°C and a holding time of 1.5-3h. The internal pressure of the pulsed ion nitriding furnace is 190-220Pa, so that when the coating material is deposited, not only does the deposition effect not deteriorate, but it is improved, thereby improving the corrosion resistance of the diverter cone and improving the wear resistance; using specific types of coating materials on the surface of the diverter cone, such as tungsten carbide composites with a hardness of 1000-2000 and a friction coefficient of 0.1-0.3, chromium nitride / diamond composites with a friction coefficient of 0.1-0.3, and chromium nitride aluminum composites with a friction coefficient of ≤0.35, can extend the service life of the diverter cone, and improve the bonding force of the coating material on the surface of the diverter cone, so that the diverter cone is not easily damaged during long-term die-casting work. The use of the diverter cone provided by the present invention in the die-casting process of aluminum products can make the molten metal flow evenly into the mold cavity. The diverter cone can withstand multiple die-casting operations, is erosion-resistant, and is not prone to cracks. DETAILED DESCRIPTION

[0027] Example

[0028] The raw materials in the embodiments are all commercially available. H13 material is purchased from Baosteel, tungsten carbide composite is purchased from Balinit, model is Balinit C, with a hardness of 1500 and a friction coefficient of 0.1-0.2, chromium nitride / diamond composite is purchased from Balinit, model is Balinit DLC STAR, with a friction coefficient of 0.1-0.2, and chromium nitride aluminum composite is purchased from Balinit, model is Balinit HELICA, with a friction coefficient of 0.25.

[0029] Example 1

[0030] This example provides a preparation process for a splitter cone, the steps are as follows:

[0031] S1: Design; S2: Forging; S3: Primary processing; S4: Heating in a vacuum heating furnace, taking out and cooling, and tempering in a tempering furnace; S5: Secondary processing; S6: Nitriding, oxidation; S7: Vapor deposition;

[0032] In step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 780°C at a heating rate of 1°C, keeping the temperature for 180 minutes, cooling to 730°C at a cooling rate of 2°C / min, and keeping the temperature for 15 minutes. The secondary heating is specifically heating to 990°C at a heating rate of 2°C, keeping the temperature for 80 minutes, and cooling to 160°C at a cooling rate of 10°C / min.

[0033] Step S4 is specifically heating in a heating furnace, taking out and cooling to 90°C in air at 25°C, and then tempering;

[0034] The tempering treatment includes primary tempering, secondary tempering and tertiary tempering. The primary tempering is specifically tempering and keeping warm at 510℃ for 6.5 hours, taking out the tempering furnace and cooling to 70℃ in 25℃ air; the secondary tempering is specifically tempering and keeping warm at 450℃ for 6.5 hours, taking out the tempering furnace and cooling to 55℃ in 25℃ air; the tertiary tempering is specifically tempering and keeping warm at 550℃ for 6 hours, taking out the tempering furnace and cooling to 25℃ in air.

[0035] Step S2: Forging is specifically to add the diverter cone material body into the hot forging machine saw for forging; Step S3: Primary processing is specifically to send the forged material obtained in S2 to the lathe for processing; Step S5: Finishing is specifically to send the processed part obtained in S4 to the CNC machine tool for further processing; Step S6: Nitriding and oxidation is specifically to send the workpiece obtained in S5 into the nitriding furnace for gas nitrogen oxidation.

[0036] The diverter cone is made of H13 material.

[0037] Step S7: Pretreatment is performed before vapor deposition. Specifically, the pretreatment is performed in a pulsed ion nitriding furnace. During pretreatment, the nitriding temperature is 510°C and the temperature is maintained for 2 hours. During pretreatment, the internal pressure of the pulsed ion nitriding furnace is 210 Pa.

[0038] In step S7 , the vapor deposition is specifically performed by depositing the coating material using a Balzers coating machine.

[0039] The coating material comprises a tungsten carbide composite, a chromium nitride / diamond composite and a chromium nitride aluminum composite, wherein the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium nitride aluminum composite in the coating material is 10:1.6:0.9.

[0040] Example 2

[0041] This example provides a preparation process for a splitter cone. Unlike Example 1, in step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 790°C at a heating rate of 2°C, holding for 160 minutes, cooling to 740°C at a cooling rate of 3°C / min, and holding for 10 minutes. The secondary heating is specifically heating to 970°C at a heating rate of 2°C, holding for 90 minutes, and cooling to 170°C at a cooling rate of 11°C / min.

[0042] In step S7 , the vapor deposition is specifically performed by depositing the coating material using a Balzers coating machine.

[0043] The coating material includes a tungsten carbide composite, a chromium nitride / diamond composite, and a chromium nitride aluminum composite. In the coating material, the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite, and the chromium nitride aluminum composite is 13:2:1.5.

[0044] Example 3

[0045] This example provides a preparation process for a diverter cone. The difference from Example 1 is that in step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 760°C at a heating rate of 1.5°C, keeping warm for 170 minutes, cooling to 700°C at a cooling rate of 3°C / min, and keeping warm for 20 minutes; the secondary heating is specifically heating to 980°C at a heating rate of 1°C, keeping warm for 90 minutes, and cooling to 170°C at a cooling rate of 12°C / min.

[0046] The tempering treatment includes primary tempering, secondary tempering and tertiary tempering. The primary tempering is specifically tempering and keeping warm at 500℃ for 5.5 hours, taking out the tempering furnace and cooling to 70℃ in 25℃ air; the secondary tempering is specifically tempering and keeping warm at 440℃ for 6 hours, taking out the tempering furnace and cooling to 45℃ in 25℃ air; the tertiary tempering is specifically tempering and keeping warm at 550℃ for 7 hours, taking out the tempering furnace and cooling to 25℃ in air.

[0047] Example 4

[0048] This example provides a preparation process for a diverter cone. Unlike Example 1, this example provides a preparation process for a diverter cone. Unlike Example 1, in step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 790°C at a heating rate of 1°C and keeping warm for 190 minutes; the secondary heating is specifically heating to 1000°C at a heating rate of 1.5°C, keeping warm for 85 minutes, and cooling to 150°C at a cooling rate of 10°C / min.

[0049] The tempering treatment includes primary tempering, secondary tempering and tertiary tempering. The primary tempering is specifically tempering and keeping warm at 500℃ for 6 hours, taking out the tempering furnace and cooling to 85℃ in 25℃ air; the secondary tempering is specifically tempering and keeping warm at 460℃ for 6 hours, taking out the tempering furnace and cooling to 55℃ in 25℃ air; the tertiary tempering is specifically tempering and keeping warm at 560℃ for 5.5 hours, taking out the tempering furnace and cooling to 25℃ in air.

[0050] Example 5

[0051] This example provides a process for preparing a diverter cone. Unlike Example 1, the pretreatment is performed in a pulsed ion nitriding furnace. During pretreatment, the nitriding temperature is 450°C and the temperature is maintained for 3 hours. During pretreatment, the internal pressure of the pulsed ion nitriding furnace is 200 Pa.

[0052] In step S7 , the vapor deposition is specifically performed by depositing the coating material using a Balzers coating machine.

[0053] The coating material comprises a tungsten carbide composite, a chromium nitride / diamond composite and a chromium nitride aluminum composite, wherein the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium nitride aluminum composite in the coating material is 8:1:1.

[0054] Example 6

[0055] This example provides a process for preparing a splitter cone, which differs from Example 1 in that no pretreatment is performed before vapor deposition in step S7. In step S7, vapor deposition is specifically performed by depositing a coating material using a Balzers coating machine.

[0056] The coating material includes a tungsten carbide composite, a chromium nitride / diamond composite, and a chromium nitride aluminum composite. In the coating material, the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite, and the chromium nitride aluminum composite is 12:1.8:1.2.

[0057] Example 7

[0058] This example provides a process for preparing a diverter cone. Unlike Example 1, the pretreatment is performed in a pulsed ion nitriding furnace. During pretreatment, the nitriding temperature is 480°C and the temperature is maintained for 2.5 hours. During pretreatment, the internal pressure of the pulsed ion nitriding furnace is 210 Pa.

[0059] In step S7 , the vapor deposition is specifically performed by depositing the coating material using a Balzers coating machine.

[0060] The coating material comprises a tungsten carbide composite, a chromium nitride / diamond composite and a chromium nitride aluminum composite, wherein the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium nitride aluminum composite in the coating material is 9:0.5:1.

[0061] Performance testing:

[0062] 1. Adhesion test of the diverter cone coating: The diverter cones obtained in Examples 1-7 were subjected to a scratch test according to GBT30707-2014. After the test, the samples were observed under an optical microscope at 200x magnification to see if there was any peeling. After immersion in a 2.5 wt% NaCl solution for 14 days, the adhesion was tested again. The results are shown in Table 1:

[0063] Table 1

[0064] Example Binding force Binding strength after 14 days 1 No peeling phenomenon No peeling phenomenon 2 No peeling phenomenon No peeling phenomenon 3 No peeling phenomenon Peeling phenomenon occurs 4 Peeling phenomenon occurs Peeling phenomenon occurs 5 No peeling phenomenon No peeling phenomenon 6 No peeling phenomenon Peeling phenomenon occurs 7 Peeling phenomenon occurs Peeling phenomenon occurs

[0065] 2. Wear resistance test: The friction coefficient of the diverter cones obtained in Examples 1-7 was tested using a friction loss meter. The lower the friction coefficient, the better the wear resistance. The results are shown in Table 2:

[0066] Table 2

[0067]

[0068]

[0069] 3. Appearance test: The diverter cones obtained in Examples 1-7 were immersed in a 0.6 mol / L hydrochloric acid aqueous solution for 7 days, taken out, and their appearance was observed. The results are shown in Table 3:

[0070] Table 3

[0071] Example Appearance 1 No cracks 2 No cracks 3 Cracks 4 Cracks 5 Cracks 6 Cracks 7 Cracks

Claims

1. A process for preparing a splitter cone, characterized in that: Here are the steps: S1: Design; S2: Forging; S3: Primary processing; S4: Heating in a vacuum heating furnace, taking out and cooling, and tempering in a tempering furnace; S5: Secondary processing; S6: Nitriding, oxidation; S7: Vapor deposition; In step S4, the heating includes primary heating and secondary heating. The primary heating is specifically heating to 750-800°C at a heating rate of 1-2°C, keeping the temperature for 160-190 minutes, cooling to 710-740°C at a cooling rate of 2-3°C / min, and keeping the temperature for 10-20 minutes; the secondary heating is specifically heating to 970-1000°C at a heating rate of 1-2°C, keeping the temperature for 70-90 minutes, and cooling to 140-180°C at a cooling rate of 9-13°C / min. Step S4 specifically comprises heating in a heating furnace, taking out and cooling to 75-110°C in air at 25°C, and then tempering; Tempering treatment includes primary tempering, secondary tempering and tertiary tempering. The primary tempering is specifically tempering and holding at 490-530℃ for 5.2-7.5h, taking out the tempering furnace and cooling to 65-90℃ in 25℃ air; the secondary tempering is specifically tempering and holding at 440-480℃ for 5.2-6h, taking out the tempering furnace and cooling to 40-60℃ in 25℃ air; the tertiary tempering is specifically tempering and holding at 540-560℃ for 5.2-7.5h, taking out the tempering furnace and cooling to 25℃ in air; The material of the diverter cone includes but is not limited to HPM1 material, H13 material, SUJ2 bearing steel, and SKD61 hot work die steel; the coating materials used on the surface of the diverter cone include tungsten carbide composite, chromium nitride / diamond composite, and chromium nitride aluminum composite; the tungsten carbide composite has a hardness of 1000-2000 and a friction coefficient of 0.1-0.3; the friction coefficient of the chromium nitride / diamond composite is 0.1-0.3, and the friction coefficient of the chromium nitride aluminum composite is ≤0.35; The nitriding and oxidation in step S6 is specifically to send the workpiece obtained in step S5 into a nitriding furnace for gas nitrogen oxidation.

2. The process for preparing the splitter cone according to claim 1, characterized in that: In step S7, pretreatment is performed before vapor deposition. Specifically, the pretreatment is performed by a pulse ion nitriding furnace. During the pretreatment, the nitriding temperature is 480-520° C., the temperature is kept for 1.5-3 hours, and the internal pressure of the pulse ion nitriding furnace is 190-220 Pa.

3. The process for preparing the splitter cone according to claim 2, characterized in that: In the coating material, the weight ratio of the tungsten carbide composite, the chromium nitride / diamond composite and the chromium nitride aluminum composite is (7-13): (1-2): (0.7-1.5).

4. An application of the preparation process of the splitter cone according to claim 1 in the field of plastic material molding.

Images