NSK launches one of the widest ranges of corrosion resistant bearing available – for use with water, acids, alkali and gases

Citation

(2003), "NSK launches one of the widest ranges of corrosion resistant bearing available – for use with water, acids, alkali and gases", Anti-Corrosion Methods and Materials, Vol. 50 No. 4. https://doi.org/10.1108/acmm.2003.12850dad.002

NSK launches one of the widest ranges of corrosion resistant bearing available – for use with water, acids, alkali and gases

NSK launches one of the widest ranges of corrosion resistant bearing available – for use with water, acids, alkali and gases

Keywords: Corrosion resistance, Bearings

NSK has launched one of the widest ranges of corrosion resistant bearings for use in arduous environments. The bearings are designed to provide outstanding performance when exposed to such mediums as water, acids, alkali and gases (Plate 2).

The new corrosion resistant bearings are part of NSK's high-tech SPACEA series. They employ a combination of materials, coatings and lubrication technologies to provide reliable performance and endure a host of industrial environments, including food processing, semi-conductor manufacturing, metal plating, chemical processing, agriculture, iron and steel manufacturing, fisheries, transportation – and many more.

Plate 2

The SPACEA corrosion resistant series is divided into nine main types, each offering graduated performance levels depending upon the application type and the prevailing operating conditions. For operation in water-based environments, four bearing types are offered: stainless steel, hybrid, molded oil and fluoride low-temperature chrome-plated bearings.

The stainless steel bearings are the base standard of the range; they are designed for high humidiy environments – as found in food processing, fisheries, chemical processing and semi-conductor equipment cleaning. The martensitic stainless steel used in these bearings is also employed for the bearing inner and outer rings in the hybrid series bearings. However, these bearings differ in that they use silicon nitride balls, fluororesin cages and waterproof grease or solid lubricant, enabling them to provide up to five times the life of pure stainless steel types in applications subject to watersplash or immersion.

The third SPACEA type for use in water borne environments is NSK's molded oil bearings.

These units employ a special solid lubricant and are for use in environments exposed to high humidity and contamination, such as water splashes and/or dust. The equipment performance is enhanced in terms of reliability and maintenance-free operation and enables real cost savings by replacing the existing, and often costly, methods of bearing lubrication.

For specialised applications in food processing, semi-conductor cleaning equipment and transportation, NSK provides fluoride low-temperature chrome-coated bearings. These have stainless steel inner and outer rings that are treated with a fluoride low-temperature chrome coating and the option of a fluororesin cage. As a result, they offer higher corrosion resistance and durability than bearings with hard chrome or electroless nickel plating.

Bearings for alkali and weak acid environments

Increasingly in modern manufacturing and process applications, rolling bearings are called upon to operate in alkali and weak acid environments. The SPACEA corrosion resistant range addresses this requirement with three bearing types; precipitation hardened stainless steel bearings, nickel alloy-coated bearings and all ceramic bearings.

Both precipitation-hardened and nickel alloy-coated bearings offer higher corrosion resistance than martensitic stainless steel types. The former is a hybrid design that includes ceramic balls and a self-lubricating fluororesin cage. The performance of nickel alloy types also exceed that of bearings employing hard chromium plating, by virtue of greater hardness. Typical areas of application for these bearings include liquid crystal and semi-conductor manufacturing, hard disk manufacturing, metal plating and food processing.

Even higher levels of corrosion resistance are provided by the first of SPACEA's all-ceramic bearing solutions. Designed to offer longer life than stainless steel and hybrid bearings, the all-ceramic bearings provide the user with a relatively low cost alternative due to the use of oxide or silicon-nitride based ceramics. In addition to their cost benefits, silicon-nitride bearing types are the choice for corrosive applications, where high temperatures and heavy-load conditions are encountered.

Highest levels of corrosion resistance for strong acid environments

The second ceramic bearing option offered by the SPACEA range is intended for use in environments where strong acids are encountered. Employing carbide-based material, these bearings offer the highest corrosion resistance of any ceramics, enabling them to provide long life in highly acidic, strong alkali and corrosive gas environments. Such conditions are routinely encountered in film cleaning systems, chemical processing, metal plating and liquid crystal and semi-conductor manufacturing equipment.

Offering a lower cost option for applications involving light loads is a range of fluororesin bearings. These provide corrosion resistance equivalent to ceramics and ten times the durability of stainless steel bearings under light loads. They are designed for use in strong acid, strong alkali and corrosive gas environments of the type experienced in various cleaning and disinfecting processes, chemical processing, plating, liquid crystal and semi-conductor manufacturing.