We used a soak time of 3.5 hours for everything that we did. We are just getting into optimizing material properties as opposed to hardening material just to get a surface hardness.
We are going to run some experiments based upon the information provided specifying 15 minutes per inch of...
ProductivityPress.com is an entire web-site pretty much devoted to Lean. They sell a number of books. Personally, I thought the Toyota Way was the easiest read of the Lean books I have read so far. Most are pretty dry but worth the time.
Currently, I am working with 3 different section diameters, 6.5", 8", and 11.5". However, my latest results were from heat treating the tensile and charpy samples only. Would that explain the low charpy? The long austenitize would cause grain size growth due to the small sample size.
I am heat treating 4340 attemting to achieve the following results (similar to ASTM A540-B23):
Tensile 145,000 psi
Yield 130,000 psi
Elongation in 2" of 12%
Reduction in area of 40%
Impact V-notch ft-lbs 25
Brinnell 302-375
I used the following process:
Heated to 1575 F for 3.5 hrs in a...
