FENSO is the brand name for a series of premium quality oils designed specially for use as heat-treating fluids. The FENSO line consists of two grades: one medium-viscosity, dual-purpose oil for both conventional quenching and marquenching; and one high-viscosity oil specifically for marquenching. Both grades are made with highly refined base oil fortified with special additives to meet the exacting requirements of heat-treating oils.
FENSO 51 is a medium-viscosity, dual-purpose oil designed for both conventional quenching and marquenching. FENSO 51 has exceptional oxidation stability, and therefore does not require replacement as frequently as conventional oils. In addition, it will leave fewer residues on quenched parts. FENSO 51 is readily removed from quenched parts with only a mild alkali wash. Because FENSO 51 will perform the jobs that previously required two different fluids, one less oil is needed in heat-treating shops. This minimises the chances of accidentally getting the wrong fluid in the quench bath.
FENSO 71 is a high viscosity, long-life oil designed specially for marquenching. It has the high flash point required in high temperature protected-atmosphere systems and it has the excellent oxidation stability required in unprotected systems (exposed to atmosphere). Because FENSO 71 has unusually fast quenching speeds, parts quenched in FENSO 71 attain the same hardness as comparable parts quenched in conventional oils at lower temperatures. Thus, it is possible to take full advantage of the minimum distortion feature of marquenching without the loss of hardness often attendant in marquenching. FENSO 71 is easily removed from quenched parts with only a mild alkali wash. Also, because of its high flash point, it minimises smoking and improves working conditions.

FENSO quench oils are important member of the Exxon/Esso brand of speciality fluids that have gained a reputation for quality consistency and reliability, even in tough applications. The use of the most modern refining techniques is a key factor in the excellent quality of these products. Like other Exxon/Esso brand products, FENSO 51 and FENSO 71 are manufactured to the highest standards of quality control.

FENSO quench oils offer the following features and potential benefits:

• Exceptionally good oxidation stability, which means lower fuel costs, lower drag-out losses, and reduced clean-up costs for the user
• High resistance to thermal and oxidation breakdown yields longer service life, less viscosity increase in service and fewer carbonaceous deposits that must be cleaned from quenched parts
• Non-corrosive to steel and residues easily removed from quenched parts with only a mild alkali wash
• Because of its dual purpose capability FENSO 51 offers savings in storage, handling and inventory costs
• The high flash point of FENSO 71 minimises smoking and improves working conditions
• Manufactured under our stringent Product Quality Manangement System (PQMS) quality control standards

The FENSO line of mineral oil products is used in quenching operations of all types and severities. Recommended applications for each product are:

• FENSO 51 is a dual-purpose oil designed for both conventional quenching and marquenching. It can be used in open quenching systems where operating temperatures are as high as 93°C and in closed systems in which temperatures are as high as 150 C
• FENSO 71 is designed specially for marquenching. It is recommended for protected-atmosphere systems where temperatures are as high as 190 C and unprotected systems (exposed to atmosphere) with quench bath temperatures up to 135 C

Based on available information, this product is not expected to produce adverse effects on health when used for the intended application and the recommendations provided in the Material Safety Data Sheet (MSDS) are followed. MSDS's are available upon request through your sales contract office, or via the Internet. This product should not be used for purposes other than its intended use. If disposing of used product, take care to protect the environment.