Normalizing is the simplest yet a very typical heat treatment process.
We are making gears+shafts for two wheelrs.
I faced problem with Normalizing of Gears & Shafts of Steel grade (JIS)
SCM415 or SCM420. Problem is after 'Normalizing' specified
Microstructure is Uniform distribution of Perlite+ferrite with bainite
< 10% & hardness limits are 80-90HRB.
I normalizing a load of 200kgs of SCM415 gears in an Electric
Normalizing f/c (heating with electrical heater) with cycle : 870=B0C -
70minutes - forced air cooling.
If I start forced air cooling just after taking the load out from the
f/c it results in Hardness in the range 84-92HRB with Bainite >25%
If I start forced air cooling after 3 minutes when the charge is out
from f/c it resulst in very good microstructre but with hardness
Ambient temp. now a days is 25-30=B0C.
Any solution to this problem.
- posted 16 years ago