Base Oil 400N-HVI

About This Product

Gear oils thickened with polymer can drift below their grade in service, because the polymer molecules are broken up in the tooth contact. Viscosity that belongs to the base oil itself does not degrade in that way. Formulators of heavy-duty industrial gear oils, axle and transmission oils and tractor fluids therefore take as much of their target viscosity as they can from a heavy neutral before turning to polymer, and Base Oil 400N-HVI is well suited to that role. Marine blenders put it into trunk piston engine oils and system oils, where its low volatility helps limit oil consumption and its high viscosity index narrows the change in viscosity from a cold start to full power.

Unlike the lighter neutrals, this grade is specified by kinematic viscosity at 100 °C, a temperature nearer to real operating conditions in heavy-duty engines and gearboxes and the reference for engine and automotive gear oil viscosity grades. The band is 9.4 – 10.4 cSt, with viscosity index min 95. A flash point of min 227 °C by Cleveland open cup is typical of a heavy cut with little volatile material and leaves ample margin in hot gear cases and crankcases. Pour point is max -6 °C and total acid number max 0.05 mg KOH/g.

Heavier distillates contain bigger, more complex molecules, so carbon residue (max 0.15 wt %) and ASTM colour (max 2.5) are allowed to be higher than on the light neutrals. Both stay within the range needed for clear gear oils and for engine oils that must keep deposits in check. In production, a heavy vacuum distillate is solvent refined and dewaxed to reach the high viscosity index class and then finished.

Set beside the 500N-HVI, it is a little lower in viscosity and paler, which makes it the preferred heavy neutral for lighter heavy-duty grades or where the finished oil should look clear. Combining it with the 150N-HVI produces the middle grades, and adding Bright Stock BS-MVI takes a blend up to thick gear and cylinder oils.

Origin is Pakistan, with indicative availability of 5,000 – 8,000 MT per month. BG Petro Chemicals supplies high-volume customers in bulk, ISO tanks or flexi bags and smaller accounts in IBC tanks or drums, and can quote custom packaging for individual projects. Each lot is issued with a certificate of analysis, and the TDS and SDS are available on request.