ExxonMobil Thermrex Series R-21

The 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. Thermrex D-10, R-21, and V-32 are mineral-oil blends carefully selected to approximate 100 SUS at 100°F. They yield consistent Relative Cooling Indices (RCI) of 95 to 160. Thermrex F-43 is a fast quench oil augmenting selected base stocks with additive technology to provide an RCI of 195. In addition, Thermrex R-21, V-32, F-43 are "gapped" to yield controlled distillation ranges from specific base stocks.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. Thermrex Series oils D-10, R-21, V-32, and F-43 are most effective with agitation at batch temperatures of less than 150°F.