Environment-friendly tellurium-free chilling coating and strong cooling coating for sand casting and preparation method of environment-friendly tellurium-free chilling coating and strong cooling coating
By preparing tellurium-free water-based quick-drying chilling coatings, the pollution and safety hazards of existing alcohol-based chilling coatings have been solved, the application scope has been broadened, the casting requirements of complex castings have been met, and environmentally friendly and safe casting effects have been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NINGBO SENSHEN NEW MATERIALS TECHNOLOGY CO LTD
- Filing Date
- 2025-12-24
- Publication Date
- 2026-05-01
AI Technical Summary
Existing tellurol-based chilling coatings suffer from heavy pollution, narrow application range, and flammable and explosive safety hazards, failing to meet the casting requirements of complex castings.
An environmentally friendly chilling coating with a tellurium-free water-based fast-drying system is prepared by using composite metal materials, natural silicate mineral materials, composite binders and organic additives, which broadens the application range and improves safety.
It achieves environmental protection and non-toxicity, high safety, and its application range has been extended to castings with a thickness of 30mm and above. It solves a variety of casting defects, meets a variety of casting process requirements, and reduces production safety risks.
Abstract
Description
Technical Field
[0001] This invention relates to the field of coating technology for casting, specifically to an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, and their preparation methods. Background Technology
[0002] To address the leakage defects caused by shrinkage porosity in complex castings such as cylinder blocks and cylinder heads during automotive casting production, many countries have developed chilling coatings for sand cores using tellurium as the main raw material. This technology can solve shrinkage porosity defects in cast iron parts with a cross-sectional thickness of up to 13 mm. However, tellurium and chromium are carcinogenic substances recognized by the World Health Organization, causing health hazards. In the 21st century, due to environmental protection requirements, Europe has begun to restrict and strictly control the use of tellurium-containing products and tellurium compounds. Tellurium-containing chilling coatings are alcohol-based coatings, using ethanol or methanol as solvents, posing safety hazards such as environmental pollution and flammability / explosiveness.
[0003] Currently, the most commonly used chilling coatings internationally are tellurol-based chilling coatings, available in two specifications, capable of resolving shrinkage defects in aluminum and magnesium alloy sections with a thickness of approximately 8mm and cast iron sections with a thickness of approximately 6mm. However, the following problems exist: The core technology relies on metallic tellurium to solve the shrinkage problem (some countries use chromium and antimony in combination, both of which are harmful to health and the environment). Metallic tellurium and its compounds are toxic substances. Tellurium will vaporize above 660 degrees Celsius, directly endangering human health and polluting the environment.
[0004] The two existing foreign-made chilling coatings have a narrow range of applications and can only solve shrinkage defects at interfaces with a thickness of about 8 mm, which cannot meet the needs of casting production.
[0005] 3. The cooling coatings produced by foreign-invested enterprises are alcohol-based, using ethanol or methanol as solvents. They are flammable and explosive hazardous materials, posing serious safety hazards during production, transportation and storage. They need to be ignited when used, releasing large amounts of carbon dioxide and organic gases, resulting in high VOC emissions. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this invention provides an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, as well as their preparation methods. This solves the problems of existing tellurol-based chilling coatings, which suffer from heavy pollution, narrow application range, and serious safety hazards due to the flammability and explosiveness of their raw materials.
[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, comprising the following raw materials: composite metal materials, new ceramic materials, natural silicate mineral materials, composite binders and organic additives.
[0008] Preferred: The composite metal material is a combination of 3-5 metals and metal oxides and 3-6 non-metallic mineral materials; The natural silicate mineral materials are: quartz powder, talc powder, corundum powder, garnet powder, andalusite powder, kyanite powder, mullite, mica powder, feldspar powder, wollastonite powder, alumina powder, graphite powder, magnesia powder, forsterite powder, calcium oxide powder, and titanium dioxide. The composite adhesive is mainly composed of inorganic adhesives, and the auxiliary additives are also mainly inorganic.
[0009] A method for preparing an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, wherein the preparation steps are as follows: Step 1: First, pre-process some of the raw materials, keeping the temperature below 60 degrees Celsius; raw materials requiring chemical treatment should be processed two days in advance to ensure the reaction is fully completed. Step 2: During production, a high-speed disperser is used. Materials are added in the order required by the process flow. The coating is thoroughly mixed and homogeneous within the specified time. Then, the conventional performance is tested, and the indicators are adjusted to meet the technical standards. After packaging, the coating is stored in the finished product warehouse. Step 3: Recheck the Baume scale and density the next day. If they meet the standards, it is acceptable.
[0010] Preferably, the processed raw materials need to be stored separately and should not be contaminated by acidic or alkaline materials.
[0011] This invention provides an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, and their preparation methods, which have the following beneficial effects: The raw materials do not contain harmful substances such as tellurium, chromium, and antimony. Based on environmental protection and quality requirements, all the main components used are environmentally friendly, non-toxic, and harmless substances.
[0012] Replacing the alcohol-based system with a water-based fast-drying system is more environmentally friendly and safer, improves the production environment, and ensures the health of personnel.
[0013] By employing composite material refrigeration technology, the rapid cooling intensity is enhanced, and the application range is broadened. The scope for solving shrinkage porosity and shrinkage cavity is expanded to over 30mm to meet the quality and production requirements of castings. At the same time, it can also solve various casting defects such as cracks, veins, pinholes, porosity, and deformation. When combined with thermal insulation coatings, it can comprehensively solve shrinkage porosity defects, extending to a cross-sectional thickness of over 35mm. It meets the requirements of various casting process technologies, has a wider range of applications, and offers significant economic benefits. In many aspects, it breaks through and surpasses the simple and singular model of foreign rapid cooling coatings. Detailed Implementation
[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0015] This invention provides a technical solution: an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, comprising the following raw materials: composite metal materials, new ceramic materials, natural silicate mineral materials, composite binders, and organic additives.
[0016] Further: The composite metal material is a combination of 3-5 metals and metal oxides and 3-6 non-metallic mineral materials; The natural silicate mineral materials are: quartz powder, talc powder, corundum powder, garnet powder, andalusite powder, kyanite powder, mullite, mica powder, feldspar powder, wollastonite powder, alumina powder, graphite powder, magnesia powder, forsterite powder, calcium oxide powder, and titanium dioxide. The composite adhesive is mainly composed of inorganic adhesives, and the auxiliary additives are also mainly inorganic. Scope of application: This series of water-based quick-drying chilling coatings for sand mold cores is suitable for cast iron parts, including gray cast iron, ductile iron, vermicular graphite cast iron, and alloy cast iron. It is also suitable for sand mold castings of aluminum alloys, magnesium alloys, copper alloys, zinc alloys, and titanium alloys. Furthermore, it is applicable to castings with sand cores in processes such as low-pressure casting, gravity casting, high-pressure casting, differential pressure casting, squeeze casting, and semi-solid casting. Main process parameters: Baumé degree (Be): 75-90 Density: 1.43-2.64 g / cm³ at 20℃ Suspensionability: ≥85% after 24 hours Gas output: ≤18-30% Application performance: Smooth and easy to apply Leveling performance: Good The paint can withstand temperatures as low as -18 degrees Celsius in winter, but it is recommended to store it indoors at a temperature of 4 degrees Celsius. In summer, it should be stored at a room temperature below 33 degrees Celsius.
[0017] A method for preparing an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, wherein the preparation steps are as follows: Step 1: First, pre-process some of the raw materials, keeping the temperature below 60 degrees Celsius; raw materials requiring chemical treatment should be processed two days in advance to ensure the reaction is fully completed. Step 2: During production, a high-speed disperser is used. Materials are added in the order required by the process flow. The coating is thoroughly mixed and homogeneous within the specified time. Then, the conventional performance is tested, and the indicators are adjusted to meet the technical standards. After packaging, the coating is stored in the finished product warehouse. Step 3: Recheck the Baume scale and density the next day. If they meet the standards, it is acceptable.
[0018] Furthermore, the processed raw materials need to be stored separately and must not be contaminated by acidic or alkaline materials.
[0019] Those skilled in the art will process the materials in this case sequentially. The specific processing and operation sequence should refer to the following working principle. The detailed methods are well-known in the field. The following mainly introduces the working principle and process.
[0020] Example: Coating Production Process: First, some raw materials undergo pretreatment, with the temperature strictly controlled below 60 degrees Celsius. Raw materials requiring chemical treatment must be treated two days in advance to ensure complete reaction. Treated raw materials must be properly stored separately to prevent contamination by acidic or alkaline materials. Production adopts... The high-speed disperser feeds materials in the order required by the process flow, ensuring the coating is thoroughly mixed and homogeneous within the specified time. Routine performance is tested, and indicators are adjusted to meet technical standards. The mixture is then packaged and stored in the finished product warehouse. The Baume degree and density are retested the following day; if they meet the standards, the coating is considered acceptable.
[0021] How to use: The sand mold chilling coating is applied to the shrinkage defects in the sand mold or core, and the coating area should be slightly larger than the area of the shrinkage defect. Before application, the surface of the sand mold core must be cleaned and repaired completely. Select a standard chilling coating model that corresponds to the cross-sectional thickness of the area with the shrinkage defect. First, be sure to stir the chilling coating thoroughly, as the active ingredient is heavy and may settle to the bottom of the packaging due to vibration during transportation. After stirring thoroughly, add a little clean water to adjust the Baumé degree to around 65-70, and apply it evenly to the sand mold core. The coating thickness should be approximately 0.6-1mm; a thicker coating will enhance the chilling effect. Because it is a water-based, fast-drying coating, it can be dried with hot air at 150-180 degrees Celsius or in an oven at 150-180 degrees Celsius. In summer, it can be dried in the sun.
[0022] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. An environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, characterized in that, It includes the following raw materials: composite metal materials, new ceramic materials, natural silicate mineral materials, composite binders, and organic additives.
2. The environmentally friendly tellurium-free chilling coating and strong chilling coating for sand casting according to claim 1, characterized in that: The composite metal material is a combination of 3-5 metals and metal oxides and 3-6 non-metallic mineral materials; The natural silicate mineral materials are: quartz powder, talc powder, corundum powder, garnet powder, andalusite powder, kyanite powder, mullite, mica powder, feldspar powder, wollastonite powder, alumina powder, graphite powder, magnesia powder, forsterite powder, calcium oxide powder, and titanium dioxide. The composite adhesive is mainly composed of inorganic adhesives, and the auxiliary additives are also mainly inorganic.
3. A method for preparing an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting, characterized in that, The preparation steps are as follows: Step 1: First, pre-process some of the raw materials, keeping the temperature below 60 degrees Celsius; raw materials requiring chemical treatment should be processed two days in advance to ensure the reaction is fully completed. Step 2: During production, a high-speed disperser is used. Materials are added in the order required by the process flow. The coating is thoroughly mixed and homogeneous within the specified time. Then, the conventional performance is tested, and the indicators are adjusted to meet the technical standards. After packaging, the coating is stored in the finished product warehouse. Step 3: Recheck the Baume scale and density the next day. If they meet the standards, it is acceptable.
4. The method for preparing an environmentally friendly tellurium-free chilling coating and a strong chilling coating for sand casting according to claim 3, characterized in that, Processed raw materials need to be stored separately and must not be contaminated by acidic or alkaline materials.