FWM® 1537

FWM® 1537 is a low carbon wrought Cobalt-Chromium-Molybdenum alloy ideal for applications in medical and aerospace industries. It has high strength, ductility, wear resistance, corrosion resistance and biocompatibility.

  ASTM F 1537 Alloy 1
Carbon <0.14
Chromium 26-30
Molybdenum 5-7
Nickel <1.0
Iron <0.75
Silicon <1.0
Manganese <1.0
Nitrogen <0.25
Cobalt Balance

Physical Properties at Room Temperature
Density 0.3 lbs/in3
Modulus Of Elasticity 35 Mpsi
Thermal Conductivity 12.6 W/mK
Coefficient of Thermal Expansion:
(20 – 100°C)
13.2×10-6 in/in/°C

Thermal Treatment

This alloy is normally solution treated at temperatures around 2000°F for one hour, followed by a rapid quench with water or compressed air to ensure optimum properties. Annealing or aging at lower temperatures may cause the precipitation of carbides or phase transformation, which can significantly reduce ductility.

Mechanical Properties

FWM® 1537 can be provided in coil form (typical size range from 0.004" to 0.45") or as straight bars (typical size range from 0.06" to 0.4"). Coiled material can be annealed or cold worked, with the mechanical properties depending on the amount of cold work. The figure below illustrates the influence of cold work on mechanical properties.

Effect of cold work on mechanical properties:

FWM® 1537 bars can be provided in three conditions:
annealed, hard and spring. The typical mechanical properties of each condition are listed in the table below.

Typical mechanical properties of FWM® 1537 bar products:
Condition U.T.S. (ksi) Y.S. (ksi) HRC Elongation (%)
Annealed 150-170 80-110 30-35 >25
Hard* 170-195 110-130 ~40 >30
Spring >230 130-150 50-52 >20


Values are typical and may not represent all diameters. Test method will affect results.

* This material condition is similar to the ASTM condition "warm worked." The properties are similar, but the material is cold worked only. No thermal processing is used to achieve these properties.

Surface Condition

FWM® 1537 develops a highly polished appearance when drawn to fine diameters. Surface roughness can be decreased by using single crystal natural diamond dies. Large diameter wires (>0.05") will be drawn by carbide dies and thus have a more textured surface. Bar products are normally centerless ground and polished, which provides a lustrous surface finish and maintains a tight tolerance for precision machining applications.


FWM® 1537 is currently used in the medical industry to make implants such as hip and knee replacements, spinal rods and screws. Due to its unique properties, FWM® 1537 has great
potential in any industrial application that requires high strength, wear and corrosion resistance, for instance in aerospace bushings and bearings.