Spring-like Stainless Steel

Widely available, one here...

http://www.steelstrip.co.uk/BSS/stainless_spring_steel.htm

Does this generally require heat treatment after forming?

Type 301 has a good corrosion resistance due to a content of 17 % Chromium and 7 % Nickel. A high tensile strength is obtained by cold rolling. Compared to Alloy 1.4301 (AISI 304) a much higher tensile strength of more than 2000 N/mm² can be reached. Because of this, 1.4310 is suitable for stainless feeler gauge stock, precision foils, stainless springs and parts of higher strength. This alloy is little magnetic and can not be held by magnetic tables of grinding machines.

Grade 420 stainless steel is a higher carbon version of 410; like most non-stainless steels it can be hardened by heat treatment. It contains a minimum of 12 per cent chromium, just sufficient to give corrosion resistance properties. It has good ductility in the annealed condition but is capable of being hardened up to Rockwell Hardness 50HRC, the highest hardness of the 12 per cent chromium grades. Its best corrosion resistance is achieved when the metal is hardened and surface ground or polished.

400 series stainless steels can be formed in the annealed state and then heat treated to the desired hardness. 300 series stainless steals are hardened by cold work and can only be softened by annealing. They can not be hardened by heat treating.

Z10 CNT 18 austenitic Stainless Steel strips cold rolled condition is exactly tailored to you requirement of hard flexible and thin material. This alloy is used in vigorously loaded Tension Torsion strip transmission assembly of several makes of helicopters.

As correctly pointed out " 300 series stainless steals are hardened by cold work and can only be softened by annealing. They can not be hardened by heat treating" by Welderman, Z10 CNT 18 is a 3XX SS Material and in fully cold work hardened state cannot be shaped without annealing and no subsequent hardening is possible by heat treatment. There fore, Z10 CNT 18 material is not suitable for your application.