Early Applications of Cobalt
Cobalt is a naturally occurring component of the Earth's crust, present in water, soil, and air. It is essential for bacteria, plants, and animals and humans in the form of vitamin B12; therefore, the cobalt content in humans and animals will never be zero. Cobalt oxides have a long history of use in glass and ceramic production. As early as 1361-1352 BC, a small glass object of deep blue and cobalt blue was found in the tomb of Pharaoh Tharakhamen; even earlier, cobalt blue was used in ceramic glazes in China.
Cobalt Metal and Cobalt-Based Alloys
Cobalt metal itself appears to have only been isolated by the Swedish scientist G. Brandt in 1735. Its metallic uses originated in the early research and inventions of Elwood Haynes in the early 1900s. In the early 1900s, he discovered cobalt-chromium alloys by fusing cobalt and chromium, and also found that they contained many other elements such as tungsten and molybdenum. Haynes reported that even when the alloy was placed in boiling nitric acid, it resisted oxidation and corrosive fumes, and showed no visible signs of rust. Since then, cobalt-chromium alloys, marked with the Stellite trademark, have been used in various fields requiring high wear resistance, such as aerospace. In the medical field, cobalt-chromium alloys were used in medical instruments in the 1920s; the first cobalt-chromium prosthetic valve was implanted in 1960. Now, due to the excellent performance of cobalt-chromium alloys, they are used in many artificial joints, including hips and knees, bridgework, and more.
Investment Casting of Cobalt-Based Alloys
Cobalt-based investment castings are widely chosen for demanding applications requiring high wear resistance, oxidation resistance, and corrosion resistance. Coupled with their excellent creep resistance, wear resistance, and surface stability under high stress conditions, cobalt-based alloys are preferred in the following applications:
Medical Implants
Food processing equipment (high wear parts)
Turbine blades
Pump casings
Rotating rings
Blades
Valve seats
Fuel injectors
Our Casting Advantages
Excellent Quality: High visual quality, excellent visual appearance.
Surface Finish: Meets or exceeds ASTM B367 requirements.
Close Tolerances: Meets or exceeds ASTM B367 requirements.
Part Size: Casting dimensions are very close to part dimensions.
Joint Castings
Cobalt-chromium alloys are most commonly used to manufacture artificial joints, including knee and hip joints, due to their high wear resistance and biocompatibility. The excellent corrosion resistance of Co-Cr alloys reduces complications with surrounding tissues during implantation, and their chemical inertness minimizes the possibility of irritation, allergic reactions, and immune responses. Cobalt-chromium alloys are also widely used to manufacture stents and other surgical implants because they also exhibit excellent biocompatibility with blood and soft tissues. The alloy composition used for orthopedic implants is described in industry standard ASTM F75: cobalt balance, containing 27% to 30% chromium, 5% to 7% molybdenum, and limits on other important elements such as manganese and silicon, less than 1%, iron, less than 0.75%, nickel, less than 0.5%, and carbon, nitrogen, tungsten, phosphorus, sulfur, boron, etc.
Our company's product R&D engineers and quality control personnel have over thirty years of experience. We use American-made CONSARC vacuum melting furnaces and select high-quality new furnace materials to manufacture medical-grade cobalt-chromium alloys, which are widely used in human implants such as bridges, knee joints, and hip joint components.
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Co-Cr-Mo Alloy Properties
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1
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High strength;
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2
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High rigidity, higher than stainless steel and titanium;
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3
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High temperature resistance;
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4
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Good wear resistance;
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5
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Good corrosion resistance;
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6
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Non-toxic and biocompatible;
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7
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Good machinability;
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8
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After polishing, a mirror finish can be achieved;
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9
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It is one of the preferred metal materials for surgical implants and orthopedic instruments.
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