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Qingdao Hi-Duratight Co.,Ltd.

Intellectual Property

Has a number of independent intellectual property rights

Quality Control

The product research and development ability is comprehensive, the management system strictly implements ISO9001-2015

Serve Clients

Long-term to provide targeted professional consulting and first-class after-sales service.

International Brands

Internationalization and diversification development strategy has become an international brand

Product Research

SiC coated graphite base / MOCVD disk / SiC coating / oxidation resistant coating / epitaxial disk

SiC coated graphite base has the characteristics of high temperature resistance, oxidation resistance, erosion resistance, high purity, acid and alkali salt resistance and organic reagent resistance, with stable physical and chemical properties. Compared with high-purity graphite, high-purity graphite begins to undergo strong oxidation at 400 ℃. Even if the temperature is not high, the powder will fall off due to oxidation in long-term application, which will attach to the workpiece and table or pollute the environment. Therefore, SiC coated graphite base is gradually replacing high-purity graphite as a new consumable material in MOCVD equipment, powder sintering, heating elements and other processes.

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Flexible graphite sheet and roll

The natural high carbon flake graphite is made by chemical treatment and rolled by high temperature expansion. The expanded graphite roll does not contain binder and filler. Therefore, it has high purity, good corrosion resistance, radioactive resistance, high / low temperature resistance, low creep relaxation rate, excellent flexibility and other special points. It has self-lubricating and impermeable property and is suitable for sealing at low pressure. Graphite roll and metal sheet can be combined into various forms of graphite composite plate.

Flexible graphite is a product that was continued at the beginning of the company's establishment. It has been actively cooperating with customers for many years. In terms of product quality, classification and packaging, it is not only suitable for domestic market, but also meets the requirements of Japan, Taiwan, Europe, India, South America and other countries and regions. The products are rich in category, strong in hierarchy and cost-effective.

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Graphite rotor / degassing rotor

Purification process of liquid aluminum alloy is the main means to improve the comprehensive properties of aluminum alloy. In the purification process, the most advanced treatment method in the world is to mix the purified gas and solvent, and use the rotary injection of graphite rotor to purify the aluminum melt. The working principle of permanent design and production of graphite rotor is: the rotating rotor will break the nitrogen (or argon) blown into the molten aluminum into a large number of dispersed bubbles, and make them disperse in the liquid metal. Bubbles in the melt depend on the gas partial pressure difference and the principle of surface adsorption to absorb the hydrogen in the melt, adsorb the oxidized slag inclusion, and are brought out of the melt surface with the rising of bubbles, so that the melt can be purified. As the bubbles are fine and dispersed, they are evenly mixed with the rotating melt, and then rotate to form a spiral shape and slowly float up. The long contact time between the bubbles and the melt will not form a continuous straight rising air flow, which significantly improves the purification effect.

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Enterprise Development History


"Internationalization" has been lasting strategic direction, the current products in addition to the sale in more than 20 domestic province also have been sold to 35 countries around the world, with persistent constantly develop new products, new technologies, in order to further expand the international market area, Qingdao Duratight Advanced Materials Co., Ltd was established in 2020, in the service of high and new technology products of international sales, to better serve the needs of customers.


Based on the continuous pursuit of the concept of healthy life, Qingdao Darsh Pinsun Furniture Co., Ltd. was established in 2018, which mainly produces the products related to seating and bedding. The product is composed by the pure natural material such as Solid wood, palm, cane, use the Mortise and tenon technology, the surface passes burnish polishing, brush plant wood wax oil or go up traditional lacquer processing and become. At the same time, the establishment of "Dashi Life" brand, leading the concept of universal benefits, health, comfort, environmental protection, the combination of traditional and modern.


Qingdao Hi-Duratight Co.,ltd. After continuous technology research and development and market research, the establishment of "Armosh" home brand, officially entered the health home industry, become the first domestic carbon as raw material home brand! Armosh's human health as its own responsibility, carbon source materials and modern technology perfect integration, so that the product can release a large number of far infrared ray and negative oxygen ions, the human body has a significant conditioning and health care role.


"Education is the foundation of a country". In 2014, from the perspective of employees' children's education, Duratight established Qingdao innertune kindergarten. On children's school adhering to the "with the classic, with children grow up, enjoy a happy life" concept of education, education through a series of characteristics, including China, anthroposophy, bilingual environment, etc., according to the characteristics of the children preschool period, literature and understanding to the practice the body browser to set life, targeted to develop the ability of children, so that the children will do and will be, will be grateful, the pursuit of truth and wisdom, develop healthy living habits and values.


The company insists on having its own research and development ability to guarantee the sustainable development of the company under the concept, after nearly ten years of industry research and professional knowledge precipitation and the introduction and training of research and development personnel. Under the background of MOCVD technology has been imported from abroad, Qingdao Duratight has been committed to the research and development of technology, to guide the promotion of domestic technology as the mission, the company transformed into a set of research and development and production as one of the high-tech enterprises, in order to promote the technological innovation in the field of chip manufacturing, with the direction of domestic instead of imports and efforts to develop. At the end of 2012, Qingdao Hi-Duratight Co., Ltd. was registered and established.

Qingdao Hi-Duratight Co., Ltd. is a joint-stock enterprise specialized in researching, developing and producing new carbon materials and graphite civil products. The company has applied for more than 30 patents, and constantly carry out the research and development of SiC coating. At the moment, it has established long-term cooperative relations with many well-known domestic and foreign enterprises.


In the continuous expansion of foreign markets, we have carried out research and development on the Indian market for a period of 5 years. According to the particularity of the Indian market and the needs of customers, we officially registered MTD Foundry Material PVT Ltd in India in May 2012. After the establishment of the company committed to the Indian market in-depth development, so that the company's international market business more mature.


Under the background of expanding domestic and foreign markets, the company has decided to enrich its product categories and further expand the market area. Therefore, in 2008, Qingdao Changsheng Carbon Industry Co., Ltd. was established, with its main products adjusted to natural graphite products, recarburizer, artificial graphite products, etc. After years of research and development and combined with customer experience in the production of recarburizer, with high carbon, low sulfur, low nitrogen and other excellent characteristics, the product can improve the strength of castings, reduce the reject rate, is the automotive foundry industry, wind power industry and other production of high-quality castings essential preferred material.


With the opening of international market environment, the company after a thorough investigation and analysis of the domestic and international market environment, in order to a wider range of services to our clients and meet the demand of the development of the enterprise, was formally established in 2006 in Qingdao long trade co., LTD., began to expand overseas market, is committed to lasting surrounding the seal of the company's products and raw materials import and export, as well as the subsequent development of other companies' products import and export business.


In the market economy environment, the company decided to change the system from a collective enterprise to a joint-stock enterprise, so that the enterprise can be more flexible and fast to adapt to and keep up with the development of the market economy. In 2004, Qingdao Changsheng Sealing Co., Ltd. was formally established as a joint-stock enterprise to produce and sell graphite products mainly including graphite paper, graphite gasket and packing ring.


To mining, purification of natural flake graphite mainly, while processing some graphite sealing products.



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  • Q :Why is the bearing made of graphite?

    A :

    Graphite material has: high temperature resistance, oxidation resistance, chemical stability, good self lubrication. Its texture is hard and brittle, its plasticity is not good, and its impact resistance is poor.

    Graphite bearings are generally used in the special conditions: lubricating oil cannot be used, low speed and heavy load, high working temperature, or acid-base liquid cannot be used, oil can not be used or metal corrosion can not be used. Graphite bearing is not suitable for high speed and impact load.

    Graphite bearing materials are divided into: pure carbon, carbon impregnated resin, carbon impregnated metal, inlaid graphite, resin hot pressed graphite. Mainly used in: high temperature kiln rotating support parts, chemical equipment rotating support parts, chemical acid and alkali pump bearings, liquid food pump bearings, textile machinery, instrument bearings, submersible pumps, mold plane bearings and other fields.

    Due to the different material and performance of graphite bearing, the type selection is very important. The same material, regular manufacturers and general small processing workshop product quality difference is larger, not cheap.

  • Q :Explain the damage reason and protection method of graphite rotor

    A :

    In the industrial purification process, it is the most advanced treatment method in the world to mix the purified gas and solvent, and use the rotary injection of graphite rotor to purify the aluminum melt. So in the process of using the graphite rotor, it is inevitable that there will be damage, so next teaches you to take measures from the causes of damage to make the graphite rotor life longer.

    The first reason for damage is high temperature oxidation: graphite is mainly composed of carbon. Visible oxidation occurs when graphite is exposed to air over 600 ℃. The products of carbon oxidation are CO and CO2, which can not protect the rotor. Generally speaking, the degassing box can not be completely closed, and most of the chambers are not filled with protective gas, so the oxidation of graphite rotor is inevitable. As a result of oxidation, the diameter of graphite rotor shaft gradually decreases until it is broken and scrapped.

    Corresponding protection measures: anti oxidation coating rotor, effectively slow down the rotor oxidation process, prolong the service life of the rotor

    The second damage reason is liquid aluminum erosion: the graphite rotor is immersed in the liquid aluminum in the degassing box, and generally rotates at the speed of 200R / min ~ 400R / min and strongly agitates the liquid aluminum, which will produce strong erosion and friction on the rotor. Especially in the liquid surface and rotor rod contact parts gradually thin, and finally will fracture scrap.

    Corresponding protection measures: anti oxidation coating rotor, high quality graphite raw material, high strength, anti erosion

    The second damage reason is the influence of the transmission system: the transmission system of the degassing device is not stable, especially the connection with the rotor is not concentric, and the rotor swings in the process of operation. On the one hand, the friction between the rotor and the sealing plug causes damage; on the other hand, the rolling of the liquid level increases, and the oxidation and erosion of the graphite rotor intensifies, speeding up the loss of the rotor.

    Corresponding protection measures: anti oxidation coating rotor, precision CNC machining, high coaxiality

  • Q :Preparation before using graphite crucible

    A :

    Because graphite crucible has high temperature resistance, high melting point and other characteristics, it is very commonly used. In addition to the need to pay attention in the process of use, the graphite crucible also needs to do the following preparations before use:

    1. Check the graphite crucible for cracks before operation. If there is no cracks, heat the graphite crucible to above 600 ° C and dry it thoroughly.

    2. There shall be no ponding around the furnace and in the pit in front of the furnace, and irrelevant articles shall not be stacked near the graphite crucible.

    3. Strictly check whether there are explosives in the charge, preheat the charge and ensure it is dry, and add the graphite crucible slowly.

    Tips: before using the graphite crucible, the above three points must be done well, otherwise it is very likely to cause the risk of explosion when using the graphite crucible.

  • Q :Introduction of the use and advantages of graphite plate as heat conducting plate

    A :

    Graphite plate has good electrical conductivity, high temperature resistance, acid and alkali corrosion resistance and easy processing. Graphite plate is the first choice for heat conduction plate, and it can also be used as anode plate, so it has a wide range of applications.

    Advantages of graphite plate:

    1. The ideal sealing material with strong sealing performance has many excellent sealing performance.

    2. Thermal stability, self lubrication, corrosion resistance, non aging, non brittle, conductive, fire resistant, etc.

    3. It has excellent corrosion resistance, high and low temperature resistance, good compression resilience and good strength.

    Application of graphite plate:

    1. Refractory: in smelting industry, graphite plate is made of graphite, which is used as protective agent for steel ingot and magnesia carbon brick for lining of smelting furnace.

    2. Conductive materials: in the electrical industry, graphite is widely used as electrode, brush, rod, carbon tube and TV picture tube coating.

    3. Wear resistant materials and lubricants: in many mechanical equipment, graphite is used as wear-resistant and lubricating materials, which can slide at the speed of 100M / s in the temperature range of - 200 ~ 2000 ℃, with little or no lubricating oil.

    4. Sealing material: flexible graphite is used as piston ring gasket and sealing ring of centrifugal pump, water turbine, steam turbine and equipment conveying corrosive medium.

    5. Corrosion resistant materials: graphite is used as utensils, pipes and equipment, which can resist the corrosion of various corrosive gases and liquids. It is widely used in petroleum, chemical industry, hydrometallurgy and other departments.

  • Q :What is the application of flexible graphite in graphite products?

    A :

    Now the application of flexible graphite is more and more extensive. Qingdao persistent high tech will explain the application field of flexible graphite for you. Flexible graphite is mainly used in these two aspects: one is to use as various filler materials; the other is to use as cushion materials.

    1. packing

    It is mainly used for dynamic sealing or static sealing of pumps, valves and kettles. The sealing method is to cut the material into the required length and width, wrap it on different metal parts, and then limit the forming on the press. The sealing packing restricted by this method is suitable for various valve parts such as stop valve, gate valve, regulating valve, ball valve and heating valve. Flexible graphite sheet can also be wound directly around the pump shaft or stem, and then pressed into the packing box with gland. The practice shows that the sealing effect of the direct winding on the shaft is not as good as the pre - limiting molding. The difference between the two methods is due to the different pressure applied and the different degree of uniformity, which results in different compaction degree.

    2. cushion material

    It is used for gasket such as pressure pad and clamp pad, etc. as sealing information of pad. Some of these materials are directly limited by expanded graphite particles, some are made by punching or cutting flexible graphite plates or composite plates, or cut into the required specifications and shapes and data features are soft and elastic, and they can be easily sealed with the sealing surface.

    Flexible graphite data: a kind of non fiber material, that is, flexible graphite is made into sheet and then pressed into sealing filler by die. Flexible graphite, also known as expanded graphite, removes impurities from natural flake graphite. After the treatment with strong oxidation and mixed acid, it becomes graphite oxide. The carbon dioxide is released by the decomposition of oxidized graphite, and the volume expands rapidly, which becomes the flexible graphite with loose texture, soft and durable.

    The main characteristics of flexible graphite are as follows:

    1. excellent heat resistance and cold resistance. The physical properties of flexible graphite can be applied to about 600 ℃ in air, from ultra low temperature of -270 ℃ to high temperature of 3650 (in non oxidation gas);

    2. high rebound rate. When the shaft or shaft sleeve is radial circular runout due to eccentric manufacturing and installation, it has the floating function to meet the requirements. Even if the graphite shows cracks, it can be well closed, and then the binding is tight to avoid leakage.

    3. good self lubrication. Flexible graphite, like natural graphite, slips easily under the action of external force, so it has lubrication, good wear reduction and small friction coefficient;

    4. excellent chemical corrosion resistance. Besides corrosion in strong oxidizing medium such as nitric acid and concentrated sulfuric acid, flexible graphite has little corrosion in other acids, bases and solvents;

  • Q :What's special about the material of graphite electrode?

    A :

    What are the characteristics of graphite electrode materials? Next, Xiaobian will introduce you one by one.

    1. Easy to polish;

    Because the cutting resistance of graphite is only 1 / 5 of that of copper, it is easier to grind and polish;

    2. Light weight;

    The density of graphite is only 1 / 5 of that of copper. When the large electrode is used for EDM, it is more suitable for the use of large mold;

    3. The loss is small;

    Because there are C atoms in the spark oil, the high temperature causes the C atoms in the spark oil to be differentiated, and forms a protective film on the surface of the graphite electrode, which compensates for the loss of the graphite electrode;

    4. Low cost;

    Due to the rising price of copper in recent years, the price of graphite is lower than that of copper in all aspects; for the universality of carbon in the same volume, the price of graphite is 30% to 60% lower than that of copper, which is relatively stable, and the short-term price is relatively small.

    5. No burr;

    After the copper electrode is processed, it needs technology to remove the burr, while the graphite electrode is processed without burr, which not only saves a lot of cost and manpower, but also simplifies the automatic production;

    6. Fast speed;

    Graphite discharge is 2-3 times faster than copper, and the material is not easy to deform. It has a significant advantage in the processing of thin rib electrode. The softening point of copper is about 1000 degrees, and the deformation is caused by heating. The progressive temperature of graphite is about 3650 degrees. In comparison, the coefficient of thermal expansion of graphite is only 1 / 30 of that of copper;

  • Q :What is the role of graphite in graphite carbon rods?

    A :

    So what is the role of graphite in graphite rods? Next, will introduce you one by one.

    1、 Graphite can prevent boiler scaling, graphite can be coated on metal chimney, roof, bridge, pipeline can be anti-corrosion and rust proof.

    2、 As conductive materials: used in the electrical industry as the anode of electrode, brush, carbon rod, carbon tube, mercury positive current device, graphite washer, telephone parts, coating of television picture tube, etc.

    3、 As wear-resistant and smooth data: graphite is often used as a smooth agent in the mechanical industry. The smooth oil can not be used in high speed, high temperature and high pressure, while graphite wear-resistant data can be used at a high sliding speed at 200-2000 ℃ without smooth oil. Many equipment transporting corrosion media, graphite materials are widely used to make piston cup, sealing ring and bearing. They do not need to add smooth oil when they work. Graphite milk is also an outstanding smooth agent in many metal processing (drawing wire and drawing pipe).

    4、 As casting, sand turning, die pressing and high temperature metallurgy data: because of the small thermal expansion coefficient of graphite and the ability to withstand the change of rapid cold and rapid heat, it can be used as a mold for glass ware. After using graphite, ferrous metal can be used to obtain the casting scale accurately, and the surface finish rate is high, and it can be used without processing or processing, so many metals are saved. The powder metallurgy process such as hard alloy is produced. The ceramic boat for pressing and sintering is usually made from graphite materials. Crystal growth crucible, regional quintessence container, support fixture, induction heater, etc. of monocrystalline silicon are all processed with high purity graphite. In addition, graphite can be used as heat insulation plate and base of vacuum smelting, high temperature resistance furnace tube, rod, plate, lattice shed and other elements.

    5、 As fire resistant materials: graphite and its products have the properties of high temperature resistance and high strength. It is used to make graphite crucible in metallurgical industry. Graphite is used as the protective agent of ingot and lining of metallurgical furnace in steel making.

    6、 Graphite can be used as pencil core, pigment and polishing agent.

    7、 Electrode: why graphite can replace copper as electrode.

    8、 Graphite has excellent chemical stability. Through the special processing of graphite, with the characteristics of corrosion resistance, good heat conductivity and low permeability, many of them are used to make heat exchanger, reverberation tank, condenser, incinerator, absorption tower, cooler, heater, filter and pump equipment. It is widely used in petrochemical, hydrometallurgy, acid-base production, synthetic fiber, paper industry and other industries, which can save a lot of metal data.

    Because the carbon rod is used at high temperature, it is easy to conduct excellent chemical stability. It has been widely used in national defense, machinery, metallurgy, chemical industry, casting, non-ferrous alloy, light and other categories, especially black carbon rods, and also used as ceramics, semiconductors, medicine, environmental protection, laboratory analysis and other categories, and has become the most widely used non-metallic materials. When cutting steel, it is not necessary to use flammable and explosive gas like oxyacetylene flame cutting, which has low cost and safe operation. It can be used to process many kinds of metals which can not be processed by gas cutting, such as cast iron, stainless steel, copper, aluminum, etc. with high efficiency and ideal results.


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  • The 16th China International Foundry Expo

    The 16th China International Foundry Expo was held in Beijing on May 16-19, 2018. Qingdao Duratight Group warm welcome domestic and foreign customers.

    March 02, 2021
  • The 14th China international casting fair

    From May 17 to May 20,2016,the 14th China international casting fair which sponsored by the Chinese Casting association was held in China international exhibition center.

    March 02, 2021
  • India foundry Exhibition 2016

    Qingdao Duratight Group President Madam Maggie, Managing Director Mr Christopher, Area Manage Mr. Eric and MTD sales manager Mr. C. Madhavan attended the annual IFEX2016 which hold at Coimbatore from Jan.29, 2016 to Jan.31, 2016, Tamil Nadu India.

    March 02, 2021