How to Heat Treat Spring Steel

Definition of Heat Treating Springs:

Wire springs are placed in an oven or furnace for a certain time and temperature to relieve stress as well as to temper the spring wire to give the spring its elasticity and memory.

China Spring Products Corp's Heat Treating Chart

Material Outer Diameter - Opens / Closes Temperature Time
Aluminum none 400º F 30 minutes
Beryllium Copper ASTM B197 Closes 1% 600º F 30 mins. - 2 hours
Beryllium Copper 25 1/2 Hard none 600º F 30 minutes
Brass none Just warm up Just warm up
Bronze none 350º 15 minutes
Chrome Silicon ASTM A401 Closes 800º F 30 minutes
Chrome Vanadium ASTM A231 Closes 800º F 30 minutes
Elgiloy (open more in salt) Opens 3% 900º F 5 hours
Hard Drawn ASTM A227 Closes 550º F 20 minutes
Hastelloy C-22 none Stress Relief @ 750 F - 840 F 30 minutes
Inconel QQ-W-390 none 700ºF - 900ºF 1 hour
Inconel No. 1 Temper Does not move 1375º F 16 hours then reduce to 700º for 1 hour
Inconel X Spring Temper none 1250º F 4 hours
Inconel X-750 AMS 5698, 5699 none 1225º F 4 hours
Inconel 600 none 900º F 1 hour
Inconel 718 none 1375º F 16 hours
Monel K 500 QQ-N-286 none 1000º F 4 hours
Maraging Flat Stock Does not move 950º F 4 hours NO LESS
Maraging Flat Does not move 850º F 30 minutes
MP35N none 1200º F 4 hours
Monel 400 AMS 7233 Does not move 600º F 1 hour
Music Wire ASTM A 228 Closes 500º F 30 minutes
Ni Span C Alloy 902 50% Cold none 900º F 5 hours
Ni Span C (on big wire) Opens some 1250º F 3 hours
Oil Tempered ASTM A 229 Closes 500ª F - 600º F 30 minutes
Premier none 600º F - 650º F 15 - 30 minutes
Rene 41 none 1400º F 16 hours
Rocket Wire Min. Tensile Strength 25KS none 525º F 2 hours
Stainless Steel 17-7 PH or 17-4 ASTM A 313 (631) Opens a little 900º F 1 hour
Stainless Steel 302/304 ASTM A 313 Opens 600º F - 650º F 30 minutes
Stainless Steel 316 ASTM A 313 (631) Does not move 700º F 1 hour
Titanium Opens (like Stainless Steel) 800º F 10 hours
Valve Oil Tempered Closes 500º F - 600º F 30 mins. or until blue on ends