sealmat
Materials
- Aug 3, 2009
- 2
We are having problems related to flatness after heat treatment on 4130 rectangular channels which a about 7" long, stamped from 0.06" sheet. The rectangular 'legs' are about 0.3" tall. We are performing a prehardening stress-releif per AMS 2759/1, followed by hardnening, quench and temper to get a final hardness of 43-47 HRC. After heat treatment, the parts are bent (concave) slightly. We want to maintain a flatness of 0.010". Austenize is being done at 1575F for 1.5 hrs. We have tried oil quench and martemper. After oil quench and subsequent temper at 575F (for 3hrs), the parts are out of flatness by 0.15-0.50" while after marquench@ 350F and 575F (for 3 hrs) temper, the parts are consistantly out of flatness by about 0.04". I am wondering if someone can recommend what we can do to improve the flatness of these channels.Are the heat treatment times and temperatures adequate? Thanks for your help