Fort Wayne Metals, a company specializing in medical grade wires and cables, has developed a high ductility and high corrosion resistance alloy called 316LVM austenitic stainless steel. This alloy is developed using an advanced process in which the metal is first electric-arc melted, followed by Vacuum Arc Remelted.
This method not only guarantees excellent homogeneity and purity, but also produces a more standardized chemistry with minimum contaminants and voids. The typical chemistry of different elements is shown in Table 1. However, this is for reference only and must not be used for specification purpose. The physical properties of the 316LVM alloy are given in Table 2.
Table 1. Typical chemistry of elements
||FWM Avg. Wt. %
Table 2. Physical properties of 316LVM alloy
|Modulus Of Elasticity
||27.9 psi x 106
Thermal Treatment of 316LVM Alloy
During the thermal treatment of the 316LVM alloy, a reducing atmosphere is generally required, but an inert gas can also be used. The alloy is completely annealed at the temperature range of 1010°C to 1121°C. All these procedures are performed in a matter of minutes. However, carbide precipitation tends to reduce corrosion resistance in the 300 series alloys, but this effect is controlled in 316LVM by reducing the carbon content.
Since stainless steels are drawn to fine diameters, they tend to develop a highly polished appearance. When single crystal natural diamond (SCND) dies are utilized to process alloys, the surface roughness can be below 5 RMS. Alloys with more than 0.040” diameters are processed using polycrystalline dies and tend to have a rougher surface than those processed with natural diamond dies. Similarly, alloys with more than 0.100" diameters will exhibit an even rougher surface as they are drawn by means of carbide dies. Further finish treatments can improve the wire’s surface.
The 316LVM alloys has been used for permanent implants for a number of years, thanks to the excellent corrosion resistance in annealed conditions. In fact, the 316LVM is used as a reference in many studies conducted on new alloys. This alloy has excellent ductility even in the cold worked condition. Applications of 316LVM include:
- Suture wires
- Skin closure staples
- Orthopaedic cables
- Bone pins
- Many small machined parts
Table 3 shows the mechanical properties of the 316LVM alloy. These are only typical values and may not indicate all diameters.
Table 3. Mechanical properties of 316LVM alloy
||% Elongation (10" gauge length)
Fort Wayne Metals’ 316LVM austenitic stainless steel has high ductility and excellent corrosion resistance. It is widely used in medical appliances as it demonstrates good corrosion resistance even in annealed conditions.
About Fort Wayne Metals
Fort Wayne Metals is a recognized leader in the research, development and production of fine grade medical wire. Our expertise lies in stainless steel, titanium and titanium alloys and specialty alloys such as Nitinol.
Our headquarters are in Fort Wayne, Indiana. We also have a production facility in Ireland as well as warehouse and sales facilities in Castlebar, Ireland to serve the European market.
Fort Wayne Metals is taking an active role in ASM International, a society dedicated to the exchange of material information. We are also active in ASTM, specifically the F-4 committee, which has authored many standards for medical wire.
This information has been sourced, reviewed and adapted from materials provided by Fort Wayne Metals.
For more information on this source, please visit Fort Wayne Metals.