ASTM F138 316LVM stainless steel is a vacuum-remelted variant of 316L, specifically engineered for surgical implant applications. The vacuum melting process (typically VAR – Vacuum Arc Remelting) significantly enhances cleanliness and microstructural homogeneity, achieving the extremely high levels of purity required for implantable devices . These advantages are essential to guarantee high fatigue strength, biocompatibility, and very good corrosion resistance in physiological environments.
Specifications & Physical Data316LVM is an austenitic stainless steel that offers excellent resistance to general corrosion, pitting, and crevice corrosion due to its molybdenum content. Its austenitic structure ensures non-magnetic properties, which is critical for MRI compatibility in medical implants . Available Forms: Round bar (annealed, medium-hard, extra-hard), sheet, plate, strip, flat bar, wire, and custom billets Surface Finishes: Hardened or ground surface (bar); pickled or work-hardened (plate) Specifications: ASTM F138 (bar/wire), ASTM F139 (sheet/strip), ISO 5832-1, UNS S31673, W.Nr. 1.4441
| Chemical Composition (Weight %) | 316LVM (ASTM F138) Specification |
|---|
| Chromium (Cr) | 17.0 - 19.0 | | Nickel (Ni) | 13.0 - 15.0 | | Molybdenum (Mo) | 2.25 - 3.50 | | Carbon (C) | 0.030 max. | | Manganese (Mn) | 2.00 max. | | Silicon (Si) | 1.00 max. | | Phosphorus (P) | 0.025 max. | | Sulfur (S) | 0.010 max. | | Nitrogen (N) | 0.10 max. | | Iron (Fe) | Balance |
| Physical Properties | Metric | Imperial |
|---|
| Density | 8.0 g/cm³ | 0.289 lb/in³ | | Melting Point | ~1500°C | ~2730°F | | Modulus of Elasticity | 187 - 193 GPa | 27.1 - 28.0 × 10⁶ psi | | Magnetic Permeability | < 1.01 (Non-magnetic) | — |
| Mechanical Properties (Annealed) | Metric | Imperial |
|---|
| Tensile Strength (min.) | 490 MPa | 71 ksi | | Yield Strength (min.) | 190 MPa | 28 ksi | | Elongation (min.) | 40% | 40% | | Hardness (HB) | 200 max. | 200 max. |
Key Advantages for Medical ApplicationsBiocompatibility: Excellent tissue compatibility and corrosion resistance in physiological environments, making it suitable for long-term implantation Vacuum Melting: The VIM+VAR process ensures exceptionally low levels of non-metallic inclusions, which is essential for high fatigue strength and durability of implantable devices Corrosion Resistance: High molybdenum content combined with low inclusion rate provides outstanding resistance to general and pitting corrosion, including resistance to intergranular corrosion as verified by the Moneypenny Strauss test Non-Magnetic: Austenitic structure ensures safe MRI compatibility for implant applications Polishability: High inclusion cleanliness and homogeneous microstructure allow optimum polishing for critical implant surfaces
Fabrication Guidelines| Process | Guidelines |
|---|
| Forging | Hot forge in 900/1150°C range; annealing required after forging to restore microstructure (carbide dissolution) | | Annealing | 1050-1120°C followed by rapid quenching to restore corrosion resistance | | Machining | Good machinability; available in annealed, medium-hard, or extra-hard forms for smaller dimensions | | Polishability | Excellent; high inclusion cleanliness and homogeneous microstructure enable optimal polishing |
ApplicationsOrthopedic Implants: Hip stems, femoral heads, knee joints, spinal rods, acetabular cups, intramedullary nails, bone screws, pins, bone and nail plates Cardiovascular: Guide wires, cardiac stents Surgical Instruments: Blood lancets, stylets, trocars, general surgical tools Dental: Dental implants, osteosynthesis components
Request a quote for ASTM F138 316LVM Surgical Steel (UNS S31673) – ESR Melted – High Fatigue Strength & Biocompatibility – Non-Magnetic – Implant Grade . Please provide: Diameter / size (round bar, plate, flat bar) Condition (annealed / medium-hard / extra-hard) Surface finish (ground / hardened) Length or weight required Quantity Destination port Any special certification requirements
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