Industrial Fastener · Washers Series
Sealing Washer / Bonded Seal
A bonded seal (also called a Dowty washer) consists of a metal washer with an inner ring of rubber vulcanized in place. When compressed by a bolt or fitting, the rubber seals against fluid leakage. Standard hardware in hydraulic and fuel system fittings.
Product Overview
Sealing Washer / Bonded Seal from HDBOLT
A bonded seal (also called a Dowty washer) consists of a metal washer with an inner ring of rubber vulcanized in place. When compressed by a bolt or fitting, the rubber seals against fluid leakage. Standard hardware in hydraulic and fuel system fittings.
Supplied by HDBOLT in Yongnian, China. Our production capacity and extensive fastener stock support repeat orders and mixed-product shipments. Contact us to confirm availability for your size, grade and finish.
Metal outer washer + bonded inner rubber seal
Carbon steel or Stainless outer washer
A bonded seal (also called a Dowty washer) consists of a metal washer with an inner ring of rubber vulcanized in place. When compressed by a bolt...
Inspection records, lot labels, certificate options, and destination-ready packing.
Technical Data
Specification range
Final dimensions, mechanical properties, finish, and packing are confirmed against the RFQ and applicable standard.
| Form | Metal outer washer + bonded inner rubber seal |
|---|---|
| Rubber Compounds | NBR (most common, oil/fuel), FKM/Viton (high temp), EPDM (water/glycol) |
| Size Range | M5 – M52 |
| Material | Carbon steel or Stainless outer washer |
Common surface finishes
Select an option to review its finish details. Exact coating system, thickness, and corrosion requirement are confirmed with the order.
Quality Control
Quality Checks from Order to Shipment
Each order is matched to the specified standard and verified at practical control points before shipment.
RFQ confirmation
Standard, size, grade, pitch, finish, certificates, packing, and destination are locked before production.
Lot verification
Critical dimensions, thread fit, markings, finish appearance, and packing labels are sampled and recorded.
Shipment approval
Photos and required reports are prepared before packing, loading and export delivery.
Buyer Questions
Frequently asked questions
What rubber compound should I use for hydraulic oil?
NBR (nitrile rubber) is the standard for petroleum-based hydraulic fluids and is suitable for most general industrial applications. For higher temperatures or aggressive fluids (fuels, solvents, brake fluid), FKM/Viton may be required. Specify the fluid type and temperature when ordering.
Ready to quote Sealing Washer / Bonded Seal?
Send the standard, size, grade, finish, quantity, packing requirement, and destination. Availability and lead time are confirmed with the inquiry.