Duplex and Super Duplex UNS S31803 Washers

The Duplex and Super Duplex UNS S31803 Washers are high-performance sealing and load-bearing components manufactured from Duplex (31803/S32205) and Super Duplex (S32750/S32760) Stainless Steels. Zeron Fasteners is a prominent manufacturer and supplier of these critical components for high-demand industrial environments. Duplex alloys are characterized by their dual-phase microstructure of approximately equal parts austenite and ferrite, which provides a unique combination of high tensile strength (nearly double that of conventional 316L SS) and superior resistance to localized corrosion (pitting and crevice) and stress corrosion cracking (SCC), especially in chloride-rich settings like seawater. The washers are essential for distributing the load from the nut and bolt head, preventing embedment, and ensuring the long-term integrity of bolted joints in extremely corrosive and high-pressure systems. Primary applications include marine engineering, chemical processing, oil and gas exploration (sour service), and pulp and paper industries. We supply these washers in common types, including Flat Washers (DIN 125, ASME B18.22.1) and Split Lock Washers (DIN 127), certified to meet ASTM, DIN, and NACE standards.

Related Products

Duplex S31803 Stud Bolts Super Duplex S32750 Nuts Duplex S32205 Hex Bolts ASTM A193 B7 Washers Nickel Superalloy Washer Super Duplex S32760 Pipe Fittings Duplex Anchor Fasteners Super Duplex S32750 Blind Flanges

Duplex (UNS S31803) Washers Chemical Composition

Element	Composition (%)
Carbon (C)	<= 0.030
Silicon (Si)	<= 1.00
Manganese (Mn)	<= 2.00
Phosphorus (P)	<= 0.030
Sulfur (S)	<= 0.020
Chromium (Cr)	21.0 - 23.0
Nickel (Ni)	4.5 - 6.5
Molybdenum (Mo)	2.5 - 3.5
Nitrogen (N)	0.08 - 0.20
PREN Value	>= 32

Duplex (UNS S31803) Washers Mechanical Properties

Property	Value
Tensile Strength (min)	>= 620 MPa (>= 90 ksi)
0.2% Yield Strength (min)	>= 450 MPa (>= 65 ksi)
Elongation (%) (min)	>= 25
Hardness (Brinell) (max)	<= 290 HB

Duplex and Super Duplex Washer Key Features

Feature	Benefit in Service
High PREN Rating	Superior resistance to pitting and crevice corrosion in chloride-rich environments.
High Yield Strength	Allows for higher torque and preload, ensuring a tighter, more stable bolted joint.
SCC Resistance	Prevents cracking in highly stressed, high-temperature, or chloride-containing service.
Cost-Efficiency	Offers performance close to exotic nickel alloys at a lower cost for many applications.