Mobil Thermrex R-21

Mobil Thermrex™ Series is a family of four quench oils for the heat treatment of alloy steels. They are comprised of selected additives and solvent-refined base stocks to provide optimum chemical and thermal stability, demulsibility, and nonferrous compatibility. The use of such ingredients results in quench oils that provide uniform steel hardness, long batch life, resistance to sludge formation, and minimum deformation. The Thermrex Series oils are excellent media for rapidly cooling alloy steels to achieve optimum strength and toughness. The selection of the particular grade of quench oil depends on the cooling rate desired to prevent cracking and distortion.