Cobalt-Chromium-Molybdenum (CoCrMo) Alloy Product Details
1. Product Overview
Cobalt-Chromium-Molybdenum Alloy (abbreviated as CoCrMo) is a category of cobalt-based wear and corrosion resistant alloys with cobalt as the matrix and chromium & molybdenum as core alloying elements. By application scenario and production process, CoCrMo alloys are mainly divided into two categories: surgical implant medical grade and industrial wear-resistant grade.
Medical-grade products are manufactured with strict control over the precipitation of impurities such as nickel. With excellent biocompatibility, they serve as a core metallic material for orthopedic implants and dental restorations.
In the industrial field, CoCrMo falls under the Stellite alloy system, with Stellite 21 as the typical industrial grade. The alloy relies on chromium to form a dense passive oxide film, delivering excellent corrosion and high-temperature oxidation resistance. Molybdenum provides solid-solution strengthening, and significantly improves pitting and crevice corrosion resistance. The alloy as a whole features outstanding galling resistance, sliding wear resistance and cavitation erosion resistance, and maintains stable mechanical strength under medium-to-high temperature conditions of 600℃ to 800℃.
2. Chemical Composition (wt.%)
Element | Industrial Grade Stellite 21 | Medical Cast Grade ASTM F75 | Medical Wrought Grade ISO 5832-12 |
Co | Balance | Balance | Balance |
Cr | 26.0 ~ 30.0 | 27.0 ~ 30.0 | 26.0 ~ 30.0 |
Mo | 5.0 ~ 7.0 | 5.0 ~ 7.0 | 5.0 ~ 7.0 |
C | ≤ 0.30 | ≤ 0.35 | ≤ 0.14 / 0.15 ~ 0.35 |
Ni | ≤ 1.0 | ≤ 0.5 | ≤ 1.0 |
Fe | ≤ 0.75 | ≤ 0.75 | ≤ 0.75 |
Si | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 |
Mn | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 |
3. Applicable Standards
All CoCrMo products from Beijing Zhongye New Material Technology Co., Ltd. are manufactured in strict compliance with the following standards, subject to customer requirements.
3.1 Chinese Domestic Standards
GB 4234.12-2024 Implants for surgery — Metallic materials — Part 12: Wrought cobalt-chromium-molybdenum alloy (identical to ISO 5832-12:2019)
YY 0117.3-2024 Cast cobalt-chromium-molybdenum alloy for orthopaedic prosthesis castings
Industrial grades comply with relevant international standards.
3.2 International Standards
ASTM F75 Standard Specification for Cast Cobalt-Chromium-Molybdenum Alloy for Surgical Implants
ISO 5832-4 Implants for surgery — Metallic materials — Part 4: Cast cobalt-chromium-molybdenum alloy
ISO 5832-12 Implants for surgery — Metallic materials — Part 12: Wrought cobalt-chromium-molybdenum alloy
UNS R30021 (Unified Numbering System for Stellite 21)
AMS 5385 (castings), AMS 5819 (bar & wire) — Aerospace grade standards
AWS ERCoCr-E — Hardfacing welding wire specification
4. Available Forms & Specifications
Beijing Wenton Technology Co., Ltd. provides custom fabrication services for all CoCrMo products. Standard product forms are as follows:
Round bars: Hot rolled, precision turned and polished bars, diameter from Φ3mm to Φ300mm, custom cut-to-length available
Plates & strips: Hot rolled heavy plates and cold rolled sheets, thickness from 0.5mm, custom dimension cutting available
Wires: Industrial hardfacing wires and medical precision wires, diameter from Φ0.1mm to Φ5.0mm
Castings: Precision cast blanks, custom manufactured per customer drawings
CNC machined parts: Precision CNC-machined components produced to customer drawings
Alloy powders: Gas-atomized powders, suitable for 3D printing, laser cladding and Plasma Transferred Arc (PTA) hardfacing processes
Mill Test Certificates (MTC) are provided with each batch. Third-party inspection reports are available upon request.
5. Key Performance Features
Excellent medical-grade biocompatibility: Strict control over the release of harmful impurities such as nickel, fully meeting the safety requirements for surgical implants.
Outstanding wear and galling resistance: Low friction coefficient in self-mated metal contact, with galling and scratch resistance far superior to conventional stainless steel and nickel-based alloys, making it the preferred material for high-end sealing pairs and friction pairs.
Comprehensive corrosion resistance: Good resistance to uniform corrosion, pitting corrosion and crevice corrosion in acidic media, seawater and high-temperature flue gas environments.
Stable high-temperature performance: Capable of long-term service at 600℃~800℃ while retaining structural strength and oxidation resistance.
High process compatibility: Suitable for precision casting, forging, CNC machining, additive manufacturing, hardfacing and other forming processes; ultra-high surface finish can be achieved after machining.
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