Coil steel Freeflex® Core

for the aerospace industry

Freeflex® Core is a hardened and tempered martensitic stainless compressor valve steel alloyed with copper. The material is characterized by: Excellent combination of high strength and high ductility Extremely high fatigue strength under bending and impact stress Excellent surface finish Very high compressive residual surface stress Low level of non-metallic inclusions Very good wear resistance Freeflex® Core compressor valve steel has excellent dimensional tolerances and flatness. Applications Valve types: Flapper valves Reed valves Check valves Fabrication Tumbling A good tumbling operation giving a round, smooth edge is necessary in order to minimize stress concentrations. Tumbling also increases the residual compressive surface stresses which gives a significant further improvement in fatigue properties. Finish Edges Edges are slit and deburred. Shaved edges can be supplied on request. Flatness Maximum out-of-flatness across and along the strip is 0.20% of the nominal strip width. Surfaces Maximum surface roughness values, cut-off 0.80 mm (0.031 in.), are shown in the table.