Material - a maraging stainless steel, specially manufactured for Reynolds by Carpenter Specialty Alloys, USA. This material undergoes a double vacuum remelt process to get achieve the necessary properties and purity. It has a very low carbon content, which has an advantage that machinability compared to e.g. AerMet 100, which is improved due to low carbide content.

• Made from cold-rolled strip steel into a tube with a highly homogenous weld, done in an inert atmosphere (specialist aerospace weld mill). The metal used is double vacuum melted by Carpenter to achieve very high purity levels that are typical of aerospace applications. Although a departure from Reynolds' preference of using seamless materials for high-end tubing, tests and cross sections of the weld area show the seam is "essentially invisible" when examined microscopically.
• Ultimate tensile strength - 1700 to 2050MPa depending on process and heat-treatment selected (853 airhardening steel UTS 1200-1400 MPa). Density is 7.79 gm/cc. Poissons ratio is 0.30.
• Yield strength 1500-1900 MPa depending on the combination of cold-working, butting, and ageing temperature. (1500 MPa is approx. twice the yield strength of Cold-worked, Stress relieved 3-2.5 titanium). At 950 F ageing temperature, yield strength should be in the 1650-1730 MPa range based on internal tests. Changing the ageing temperature can increase elongation.
• Stiffness Modulus (E) is 200 GPa, similar to other steel alloys. If higher stiffness is required when lighter tubes are used, advantage can be taken of the higher yield strength by using slightly oversize but thin wall tubes with a lower overall weight.

FRAME BUILD OPTIONS using 953

• Can be TIG welded with AWS ER630 wire, brass braze or silver brazed using recommended filler wires.
• Corrosion resistance is similar to type 410 stainless steels. In normal use, brown staining of the surface does occur due to sweat, salty roads etc if not protected/painted. The staining can be removed with "scotch-brite" or an equivalent, and trials have shown that this is a superficial stain that does not weaken the tubes.
• The recommended method of building is the use of pre-aged tubing, so frame builders can fabricate the frames, but assume mitre and cutting could be slow due to tube hardness. Purging whilst welding the frame is highly recommended . This would reduce possible contamination on the inner surface of the weld joints, improving corrosion resistance.
• Frame alignment should be carried out before ageing if needed but we do not expect jigs to be needed, as this is a relatively low temperature for steel heat-treatment.