It’s well known that quenching most alloyed steels starting from AISI 4140 to high speed steels in water, brine , or sometimes oil will cause cracking and distortions.
in industry oil quenching sometimes replaced by molten salt, which considered better than oil in decreasing crack probability and this advantage attributed to uniform cooling provided by salt bath compared to other quenching mediums.
cracks and distortions caused by water or brine quenching usually attributed to rapid cooling , but sometimes they attributed to non-uniform cooling caused by vapor blanket. that’s so confusing!!
it is expected to obtain uniform cooling by quenching steel in high concentration salt solution "nearly saturated solution" thanks to large amounts of ion particles which disturb vapor blanket, but these type of solutions will also have high cooling rate compared to oil. such rapid cooling usually attributed to be the of quench cracks in water quenching !
O1 steel can’t fully hardened in parts larger than 1 inch!
so my problem if it is safe to quench thick parts of such low hardenability steels in very high concentration salt solution which are expected to combining uniform cooling with relatively high speed cooling to fully harden thick parts of such low hardenability steel ?