Preparation method and mold of cast iron white sample for direct-reading spectrometry detection
By using a rapid preparation method involving high-frequency induction heating and water-cooled copper molds, the problem of sample defects caused by graphite precipitation in traditional white cast iron methods has been solved, enabling efficient and accurate detection of cast iron samples and simplifying the preparation process.
Patent Information
- Application Number
- CN202511896749.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-03-17
AI Technical Summary
Traditional white cast iron conversion methods cannot completely suppress graphite precipitation, resulting in numerous internal defects in cast iron samples, which affects the accuracy and efficiency of spectral analysis, and the preparation process is cumbersome.
A rapid preparation method using high-frequency induction heating and water-cooled copper molds was adopted. The cast iron was rapidly melted by high-frequency induction heating and then rapidly cooled in a water-cooled mold at a cooling rate of more than 100°C/second to form a cast iron sample with a full white cast iron structure.
It achieves efficient preparation of cast iron samples, with dense and defect-free sample structure, significantly improved accuracy and reproducibility of test results, simplified process, and reduced labor and time costs.
Smart Images
Figure CN121678299A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal material analysis and detection, in particular to a cast iron white mouth sample preparation method and mold for direct reading spectrometry detection. BACKGROUND
[0002] Direct reading spectrometry is the mainstream method for rapid analysis of the chemical composition of cast iron. However, the graphite morphology in cast iron (such as flaky graphite in gray cast iron) can seriously affect the accuracy of the analysis results. Graphite causes the metal matrix to be discontinuous, has poor stability when excited, and its chemical composition (pure carbon) cannot represent the solid solution carbon in the matrix, resulting in a serious underestimation of the detection results of elements such as carbon and silicon and large fluctuations; to solve this problem, the cast iron sample must be treated to a "white mouth" state, i.e., by rapid cooling to suppress the precipitation of graphite, so that all the carbon is solidified in the form of carbide in the matrix, thereby obtaining a sample with uniform composition and dense structure.
[0003] Traditional white mouth methods mostly use ordinary sand molds or metal molds for casting, with slow cooling speeds. For high-carbon equivalent cast iron, especially thick-section samples, it is difficult to ensure complete white mouth, and internal shrinkage, porosity and other defects are prone to occur in the sample, affecting the analysis accuracy. In addition, the samples prepared by traditional methods often need to be subjected to subsequent processing such as turning and grinding, which is a cumbersome process with low efficiency. SUMMARY
[0004] The present application aims to provide a cast iron white mouth sample preparation method and mold for direct reading spectrometry detection and a processing device thereof to solve the problems raised in the background.
[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a cast iron white mouth sample preparation method for direct reading spectrometry detection, the cast iron white mouth sample preparation method for direct reading spectrometry detection comprising the following steps: S1, under the protection of high-purity inert gas, rapidly melting the cast iron sample using a high-frequency induction heating device; S2, rapidly pouring the completely molten metal liquid into a mold with an internal forced water cooling system; S3, the mold rapidly cools the metal liquid at a cooling rate greater than 100℃ / s to form a completely white mouthed, flat-shaped spectral analysis sample that does not require secondary processing.
[0006] Further, in step S1, the melting temperature of high-frequency induction heating is 1400℃-1550℃, and the holding time is 5-15 seconds.
[0007] Further, in step S1, the high-purity inert gas is high-purity argon.
[0008] Further, in the step S2, the pouring process is completed within 3 seconds.
[0009] Further, in the step S3, the cooling of the sample is completed within 10-20 seconds after pouring, and the sample is directly taken out of the mold The application discloses a sample preparation mold for white-cast iron of cast iron for direct-reading spectrometric detection, and relates to the technical field of sample preparation.
[0010] Further, the pouring opening is in a funnel type structure, and an exhaust hole is arranged on one side of the inner part of the upper mold close to the pouring opening.
[0011] Further, the diameter of the exhaust hole is 0.5 mm, and the thickness of the forming cavity is 5 mm.
[0012] Further, connecting blocks are arranged at four corners of the outer sides of the upper mold and the lower mold, and a positioning pin is slidably arranged in the inner part of one group of the connecting blocks.
[0013] Further, a water inlet one is arranged on one side of the upper mold, and a water outlet one is arranged on the other side of the upper mold, a water inlet two is arranged on one side of the lower mold, and a water outlet two is arranged on the other side of the lower mold.
[0014] The application provides a sample preparation method and mold for white-cast iron of cast iron for direct-reading spectrometric detection and a processing device thereof, and has the following beneficial effects: 1. The application combines high-frequency rapid melting and ultrafast cooling of a water-cooled copper mold, fundamentally suppresses graphite precipitation, ensures 100% white structure for high-carbon equivalent cast iron, completely solves the problem of inaccurate detection of carbon and silicon elements in spectral analysis, and greatly improves the reproducibility and accuracy of direct-reading spectral analysis.
[0015] 2. The application only needs 1-2 minutes for the whole process from sample melting to sample taking out, is much faster than a traditional sample preparation method, and realizes efficient closed loop of sample preparation and analysis, greatly shortens the detection period, and simultaneously, the special water-cooled copper mold has long service life and simple process flow, is easy to realize automatic operation, and can be used for batch sample preparation by one person, has excellent batch-to-batch and batch-to-batch reproducibility, significantly reduces the labor and time cost of daily detection in a laboratory, and meets the demand of large-scale rapid detection. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1This is a schematic diagram of the overall structure of a method for preparing cast iron white cast iron samples for direct reading spectroscopy detection according to the present invention; Figure 2 This is a schematic diagram of the unfolded structure of a method for preparing cast iron white cast iron samples for direct reading spectroscopy detection according to the present invention.
[0017] In the diagram: 1. Upper mold; 2. Lower mold; 3. Sprue; 4. Vent hole; 5. Connecting block; 6. Positioning pin; 7. Inlet 1; 8. Molding cavity; 9. Outlet 1; 10. Outlet 2; 11. Inlet 2. Detailed Implementation
[0018] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.
[0019] like Figure 1 As shown, a method and mold for preparing cast iron white cast iron samples for direct-reading spectroscopic detection are disclosed. The method and mold for preparing cast iron white cast iron samples for direct-reading spectroscopic detection include the following steps: S1. Under the protection of high-purity inert gas, the cast iron sample is rapidly melted using a high-frequency induction heating device. In step S1, the melting temperature of the high-frequency induction heating is 1400℃-1550℃, and the holding time is 5-15 seconds. In step S1, the high-purity inert gas is high-purity argon. High-frequency induction heating is fast and has high thermal efficiency, which can quickly cross the graphitization temperature range of cast iron, reduce element burn-off and oxidation. Inert gas protection can prevent the molten metal from oxidizing and ensure the authenticity of the composition. S2, the completely molten metal is quickly poured into a mold with an internal forced water cooling system. In step S2, the pouring process is completed within 3 seconds. S3, the mold rapidly cools the molten metal at a cooling rate greater than 100℃ / second to form a completely white, flat spectral analysis sample that requires no secondary processing. In step S3, the cooling of the sample is completed within 10-20 seconds after pouring, and the sample is directly taken out after opening the mold.
[0020] like Figures 1-2As shown, a cast iron sample preparation mold for direct reading spectrometry detection, which applies the cast iron sample preparation method for direct reading spectrometry detection, the cast iron sample preparation mold for direct reading spectrometry detection, including upper die 1, lower die 2, pouring gate 3, exhaust hole 4, connecting block 5, positioning pin 6, water inlet one 7, forming cavity 8, water outlet one 9, water outlet two 10, and water inlet two 11, one side of the upper die 1 is provided with the lower die 2, and the pouring gate 3 is opened in the inside of the upper die 1, one side of the upper die 1 is provided with the water inlet one 7, and the other side of the upper die 1 is installed with the water outlet one 9, one side of the lower die 2 is provided with the water inlet two 11, and the other side of the lower die 2 is installed with the water outlet two 10, through the design of the water inlet one 7, the water outlet one 9, the water outlet two 10 and the water inlet two 11, it is connected with the external circulating cooling water system, which ensures that the cooling water continuously and quickly takes away the heat of the mold, keeps the mold in a low temperature state, the connecting block 5 is installed at the outside four corners of the upper die 1 and the lower die 2, a group of connecting blocks 5 are slidably provided with positioning pins 6 inside, the pouring gate 3 is in the form of a funnel structure, and the exhaust hole 4 is opened in the side of the inside of the upper die 1 close to the pouring gate 3, the diameter of the exhaust hole 4 is 0.5mm, the thickness of the forming cavity 8 is 5mm, after the upper die 1 and the lower die 2 are closed, a flat forming cavity 8 is formed between the contact surfaces thereof, the thickness of the forming cavity 8 is designed to be 5mm, the flat design greatly increases the specific surface area of the sample, shortens the distance from the thermal center to the mold wall, which is beneficial to the rapid heat dissipation, and is the key to realize the ultra-fast cooling, through the design of the exhaust hole 4, it ensures that the air in the cavity is smoothly discharged during pouring, avoiding the generation of porosity defects, the forming cavity 8 is arranged between the upper die 1 and the lower die 2, the upper die 1 and the lower die 2 are made of high-strength and high-thermal-conductivity copper alloy such as chromium-zirconium-copper, and have a labyrinth circulating waterway inside, which is connected between the water inlet one 7 and the water outlet one 9, and another group of labyrinth circulating waterways are connected between the water outlet two 10 and the water inlet two 11.
[0021] In summary, combined with Figures 1-2As shown, the working principle of the cast iron white sample preparation method and mold for direct reading spectrometry detection is as follows: about 20g of cast iron drill chips are placed in an alumina crucible, the electromagnetic induction effect of the high-frequency induction heating device is used to generate eddy current in the cast iron and quickly heat it, and the melting temperature of 1400-1550 DEG C can be reached within 30 seconds, the core advantage of high-frequency induction heating is high thermal efficiency and fast heating speed, which can make the cast iron quickly pass through the graphitization sensitive interval of 700-900 DEG C, reduce the time window of graphite precipitation from the root, and the heating process is carried out in a high-purity argon protection atmosphere, after vacuumizing, argon is filled to micro-positive pressure, argon as an inert gas can isolate air to avoid the oxidation reaction of molten cast iron with oxygen, and prevent the loss of carbon, silicon and other easy burning elements, ensure that the composition of molten metal liquid is completely consistent with that of the original cast iron sample, lay a foundation for the authenticity of the subsequent detection result, keep the holding time for 5-15 seconds after melting, the purpose is to make the metal liquid composition uniform mixing, eliminate local component segregation, and ensure the composition uniformity of the final sample, after holding, quickly tilt the furnace body, make the metal liquid flow into the pouring opening 3 of the water-cooled mold through the pouring cup, the whole pouring process is strictly controlled within 3 seconds, the core function of rapid pouring is to reduce the exposure time of metal liquid in the air, avoid secondary oxidation and temperature drop, ensure that the metal liquid fills the forming cavity 8 with enough temperature and fluidity, the pouring opening 3 adopts funnel type structure, the flared design can guide the metal liquid to flow into the cavity quickly and stably, avoid splashing and turbulence, at the same time, shorten the flow path of metal liquid, reduce temperature loss, a diameter of 0.5mm exhaust hole 4, metal liquid filling cavity 8, the air in the forming cavity 8 can be quickly discharged through the exhaust hole 4, avoid air retention to form air hole, shrinkage and other defects, ensure that the sample surface is smooth, the inside is dense, meet the requirements of sample surface quality of spectrum detection, the upper die 1 and the lower die 2 of the mould are made of high-strength, high-thermal-conductivity chromium-zirconium-copper alloy, can quickly conduct the heat of the metal liquid, at the same time, the inside of the mould has a labyrinth circulating waterway, respectively connected with water inlet 7, water outlet 1 9, water outlet 2 10 and water inlet 2 11, connected with external circulating cooling water system, after the cooling water is connected with external circulating cooling water system, the cooling water can continuously and uniformly take away the heat of the mould, so that the mould always keeps low temperature state, precooling, after the upper die 1 and the lower die 2 are combined to form the flat forming cavity 8 with a thickness of 5mm, the specific surface area of the sample is greatly increased, the heat dissipation is increased, the distance from the thermal center of the sample to the mould wall is shortened, the heat transfer resistance in the sample is reduced, the heat is quickly discharged, the realization of the superfast cooling rate, through the synergistic effect of the high-thermal-conductivity mould, the labyrinth water cooling and the flat forming cavity 8, the cooling rate of the metal liquid in the forming cavity 8 can reach more than 100 DEG C / s, which is much higher than the critical cooling rate required for graphite precipitation, the superfast cooling can force the solidification process of cast iron to skip the graphitization stage, the carbon atoms cannot form graphite crystals, but can only be dissolved in ferrite or cementite, finally forming a full white structure with a white section and no black point graphite, the cooling and mould opening can be completed within 10-20 seconds after pouring, so that the short-time cooling can ensure complete white porosity and avoid adhesion between the mould and the sample due to long-time contact, and the detection efficiency is improved. After the sample is cooled to room temperature in the air, it is directly placed on the direct-reading spectrometer for analysis, and compared with the chemical infrared carbon and sulfur instrument and the titration method, the detection results of the main elements such as carbon, silicon, phosphorus and sulfur of the sample prepared by the method are highly consistent with the standard values, the relative deviation is less than 2%, and the repeatability RSD is better than 0.5%.
[0022] The embodiments of the present application are given for example and description, and are not exhaustive or limit the present application to the disclosed forms. Many modifications and changes are obvious to those skilled in the art. The embodiments are selected and described to better illustrate the principles and practical application of the present application, and to enable those skilled in the art to understand the present application so as to design various embodiments with various modifications suitable for specific purposes.
Claims
1. A method for cast iron hardening sample preparation for direct reading spectrography, characterized in that, The cast iron white sample preparation method for direct reading spectrometry detection comprises the following steps: S1, under the protection of high-purity inert gas, the cast iron sample is rapidly melted by a high-frequency induction heating device; S2, the completely molten metal liquid is rapidly poured into a mold with an internal forced water cooling system; S3, the mold rapidly cools the metal liquid at a cooling rate of more than 100 ℃ / s to form a completely white and flat spectral analysis sample without secondary processing.
2. A method for preparing a white-painted cast iron sample for direct-reading spectrographic detection according to claim 1, characterized in that, In the step S1, the melting temperature of the high-frequency induction heating is 1400-1550 ℃, and the holding time is 5-15 seconds.
3. A method for preparing a white-painted cast iron sample for direct-reading spectrographic detection, according to claim 1, characterized in that, In the step S1, the high-purity inert gas is high-purity argon.
4. A method for preparing a white pitted cast iron sample for direct reading spectrographic detection according to claim 1, characterized in that, In the step S2, the pouring process is completed within 3 seconds.
5. A method for preparing a white-painted cast iron sample for direct-reading spectrographic testing as defined in claim 1, wherein, In the step S3, the cooling of the sample is completed within 10-20 seconds after pouring, and the sample is directly taken out of the mold.
6. A cast iron hardening sample preparation mold for direct reading spectrographic detection, characterized by, The cast iron white sample preparation mold for direct reading spectrometry detection applies the cast iron white sample preparation method for direct reading spectrometry detection in the above claims 1-5, and the cast iron white sample preparation mold for direct reading spectrometry detection comprises an upper mold (1) and a forming cavity (8), one side of the upper mold (1) is provided with a lower mold (2), and an inner part of the upper mold (1) is provided with a pouring opening (3), and the forming cavity (8) is arranged between the upper mold (1) and the lower mold (2).
7. A cast iron hardening sample preparation mold for direct reading spectrographic detection according to claim 6, characterized in that, The pouring opening (3) is in a funnel structure, and an inner part of the upper mold (1) close to the pouring opening (3) is provided with an exhaust hole (4).
8. A cast iron hardening sample preparation mold for direct reading spectrographic detection according to claim 7, characterized in that, The diameter of the exhaust hole (4) is 0.5 mm, and the thickness of the forming cavity (8) is 5 mm.
9. A cast iron hardening sample preparation mold for direct reading spectrographic detection according to claim 6, characterized in that, The outer sides of the upper mold (1) and the lower mold (2) are provided with connecting blocks (5) at four corners, and an inner part of a group of the connecting blocks (5) is provided with a positioning pin (6).
10. A cast iron hardening sample preparation mold for direct reading spectrographic detection according to claim 6, characterized in that, One side of the upper mold (1) is provided with a water inlet one (7), and the other side of the upper mold (1) is provided with a water outlet one (9), one side of the lower mold (2) is provided with a water inlet two (11), and the other side of the lower mold (2) is provided with a water outlet two (10).