Stainless Steel Bonded Seals PPM, PPG (Viton® / FKM Seals)

Self-centering metal-rubber washer (bonded seal) made of AISI 316 / 316L (1.4571) stainless steel and a fluoroelastomer sealing insert Viton® (FPM / FKM 80° Shore A) is an uncompromising solution designed for operation in the most demanding hydraulic power, pneumatic, and chemical industry installations.

Usit / Bonded Seals type elements with acid-resistant and high-temperature sealing eliminate the need for Teflon tapes, hemp, or liquid thread sealants. During tightening, the outer ring limits the deformation of the rubber lip, and the flexible Viton ring creates a durable, pressure-and vibration-resistant face seal.

Structure and Properties of Viton® Material (FPM80)

PPM/PPG washers prove themselves wherever a standard bonded seal made of galvanized steel and NBR rubber undergoes accelerated wear or leakage due to corrosion, high temperatures, or aggressive chemical substances.

The elastomer used FPM80 (Viton with a hardness of 80° Shore A) is distinguished by excellent resistance to hydraulic oils, fuels, lubricants, solvents, and many aggressive industrial media. It maintains full elastic properties and tightness in extreme operating conditions.

Why Choose AISI 316 Stainless Steel Washers with Viton Sealing?

• Exceptional temperature resistance: Operation in the range from -30°C to even +200°C / +250°C, where standard NBR rubber hardens and carbonizes.
• Acid resistance and corrosion protection: The ring made of acid-resistant AISI 316L stainless steel ensures complete resistance to salt water, acids, bases, and industrial chemicals.
• Self-centering lip design: The self-centering design facilitates precise placement of the washer on the thread and prevents shifting during assembly.
• Durability and reusability: The outstanding shape memory of the fluoroelastomer increases the durability of connections and limits the risk of leakage under high pressure.

Wide Range of Thread Sizes

In the HYDRON store offer, you will find stainless steel Viton washers adapted to most standard threaded connections:

• Metric versions PPM (AISI 316 / Viton): From M8, M10, M12, M14, M16, M18, M20, M22, M24, M27 up to M30, M33 and M36.
• Inch versions PPG (AISI 316 / Viton – BSP / NPT / JIC): From G 1/8", G 1/4", G 3/8", G 1/2", G 3/4", G 1", G 1.1/4", G 1.1/2" up to G 2".

Industrial Application

FKM/FPM acid-resistant steel washers are used in, among others:

• High-temperature power hydraulics: Systems operating near engines, furnaces, and sources of hot working oil.
• Marine and offshore industry: Ship decks, hydraulic winches, and drilling platforms exposed to constant contact with salt water.
• Chemical and petrochemical industry: Transmission pipelines, units, and fuel-oil systems.
• Food, pharmaceutical, and pneumatic systems: Linear systems subjected to regular sterilization and washing in CIP systems.

Frequently Asked Questions (FAQ)

What is the difference between a stainless steel Viton washer and a standard NBR bonded seal?

A standard washer is made of galvanized steel and NBR rubber (operating temperature up to approx. +100°C). The stainless version has an AISI 316L steel ring and Viton® (FPM) rubber, which allows operation in temperatures up to +200°C / +250°C and provides full resistance to acids, chemicals, and marine corrosion.

Are stainless steel Viton washers reusable?

Although Viton is characterized by outstanding shape memory and aging resistance, for safety reasons, it is recommended to use a new washer for each disassembly of a high-pressure threaded connection to guarantee 100% tightness.