Selecting the right washer material is as important as selecting the right washer type. The material determines how a washer performs in its operating environment, its resistance to corrosion, ability to handle temperature extremes, electrical properties, weight, and long-term service life. A washer made from the wrong material may meet the dimensional requirements but fail prematurely, damage mating surfaces, or create problems that are difficult to trace back to the original specification.
This article covers the metals, specialty alloys, non-metals, and engineering plastics available from Superior Washer and Gasket, including grades, key properties, and the environments they are commonly found in.
The quick reference table below provides an overview of all materials covered. Each material group is then covered in detail in the sections that follow.
Editor's Note: The information provided in this article is intended for general informational purposes only and should not be interpreted as engineering, design, material selection, or application-specific guidance. Material requirements and specifications vary by application and should be evaluated according to individual project requirements.
Washer Material Quick Reference
Use the table below to identify the material group most relevant to your application, then refer to the corresponding section for grade-level detail.
| Material | Common Grades/Types | Key Properties | Corrosion Resistance | Commonly Found In |
| Stainless Steel | 301, 302, 304, 316 | Strength, durability | 304: Good; 316: Excellent | Industrial, marine, outdoor |
| Brass | Alloy 260 | Conductivity, machinability | Good | Electrical, instrumentation |
| Copper | Alloy 110 | High conductivity, thermal | Good | Grounding, electrical |
| Phosphor Bronze | Phosphor Bronze | Spring-like, fatigue resistance | Good | Electrical connectors, springs |
| Aluminum | 1100, 2024, 3003, 5052, 6061 | Lightweight, fabricable | Good | Aerospace, electronics, OEM |
| Carbon Steel | High Carbon, Low Carbon | High strength, cost-effective | Low (requires coating) | Heavy equipment, industrial |
| Nylon | Nylon 6/6 | Non-conductive, lightweight | Excellent | Electrical, chemical, general |
| PTFE / PVC / Neoprene | Various | Chemical resistance, sealing | Excellent | Chemical processing, sealing |
| Engineering Plastics | Delrin®, Phenolic, Celcon, Nylatron | Structural non-metal, low friction | Good-Excellent | Mechanical, electrical assemblies |
| High-Performance Films | Kapton, Mylar, Fiberglass, Mica | High-temp insulation, dielectric | Excellent | Electronics, aerospace, high-temp |
Metal Washer Materials and Grades
Metals make up the majority of industrial washer applications. The choice of metal, and the specific grade within that metal family, determines how the washer holds up to mechanical load, environmental exposure, temperature, and chemical contact. The sections below cover each metal group stocked by Superior Washer, including the grades available and the environments they are commonly found in.
Stainless Steel
Stainless steel is one of the most widely used washer materials across industrial, commercial, and defense applications. It offers a practical combination of strength, durability, and corrosion resistance that covers a broad range of operating conditions. Superior Washer stocks stainless steel flat washers in multiple grades. Browse the stainless steel washers collection.
Grades 301 and 302 are general-purpose stainless steel grades offering good corrosion resistance and strength. Grade 301 has higher strength and is commonly found in spring applications and high-stress assemblies. Grade 302 is a general-purpose grade commonly found in industrial fastening applications.
Grade 304 is the most common stainless steel grade in general industrial use. It offers good corrosion resistance in most environments including moisture, mild chemicals, and outdoor exposure, and is commonly found in industrial machinery, manufacturing equipment, and general fastening applications.
Grade 316 contains molybdenum, which provides enhanced resistance to chloride-induced corrosion. It is commonly found in marine environments, coastal installations, chemical processing equipment, and other applications where 304 may not provide sufficient protection. See the 316 stainless steel washers collection.
Brass, Copper, and Phosphor Bronze
Brass, copper, and phosphor bronze are grouped together because they share a common set of properties: good to excellent electrical conductivity, corrosion resistance in many environments, and machinability. Each offers each offers a distinct performance profile for specific applications. Browse brass washers, copper washers, and phosphor bronze washers.
Brass Alloy 260 offers good electrical conductivity, corrosion resistance, and machinability. It is commonly found in electrical assemblies, instrumentation, grounding systems, and applications requiring a non-ferrous fastener component with reliable performance in moderate environments.
Copper Alloy 110 is commercially pure copper, offering the highest electrical and thermal conductivity of any washer material in this group. It is commonly found in grounding applications, power distribution connections, and heat-sensitive electrical assemblies where conductivity is the primary requirement.
Phosphor Bronze combines spring-like resilience with good fatigue resistance, electrical conductivity, and corrosion resistance. It is commonly found in electrical connectors, spring contacts, and applications that require a material with both conductivity and the ability to maintain its properties under repeated stress.
Aluminum
Aluminum offers a lightweight alternative to steel and copper-based materials, with good natural corrosion resistance and ease of fabrication. It is commonly found in applications where weight reduction is a consideration alongside adequate mechanical performance. Superior Washer stocks aluminum flat washers in multiple grades, see the aluminum washers collection.
Grade 1100 is commercially pure aluminum with excellent corrosion resistance and formability. It is commonly found in general industrial, electrical, and non-structural applications.
Grade 2024 is a higher-strength aluminum alloy. It is commonly found in aerospace and structural applications where weight savings are required alongside greater mechanical load capacity.
Grade 3003 offers good corrosion resistance and formability at moderate strength. It is commonly found in general OEM and industrial applications.
Grade 5052 provides strong corrosion resistance, including in marine environments. It is commonly found in transportation, marine, and outdoor assemblies.
Grade 6061 is a versatile structural grade with good strength and corrosion resistance. It is commonly found across aerospace, automotive, and general manufacturing applications.
Carbon Steel
Carbon steel washers offer high strength and load-bearing capacity at a lower cost than stainless or specialty alloy alternatives. They are commonly found in heavy equipment, industrial machinery, and structural fastening applications where corrosion resistance is provided by the operating environment or an applied coating. Browse high carbon steel washers and low carbon steel washers.
High Carbon Steel has greater hardness and wear resistance compared to low carbon grades. It is commonly found in applications requiring higher strength and durability under load.
Low Carbon Steel is more ductile and easier to form. It is commonly found in general industrial fastening, structural applications, and metric hardware where formability and cost-effectiveness are priorities. Carbon steel washers are available in both standard and metric sizing.
Non-Metal and Engineered Plastic Washers
Non-metal washers, such as rubber washers, serve a different set of functions from metal washers: electrical insulation, chemical resistance, sealing, vibration dampening, and weight reduction. Superior Washer stocks a broad range of non-metal and engineered plastic options across several material families.
Common Non-Metal Washers
Nylon 6/6 is one of the most widely used non-metal washer materials. It is non-conductive, lightweight, chemically resistant, and has low friction properties. It is commonly found in electrical systems, chemical environments, and general industrial assemblies where a non-metal fastener component is required. See the nylon washers collection.
PTFE (polytetrafluoroethylene) offers extremely low friction and outstanding resistance to a wide range of chemicals. It is commonly found in chemical processing, pharmaceutical, and food processing applications where chemical compatibility is the primary selection criterion. See the PTFE washers collection.
PVC and Neoprene provide good chemical and weather resistance with cushioning and sealing properties. They are commonly found in plumbing, HVAC, electrical enclosures, and outdoor applications. Browse PVC washers and Neoprene washers.
Fiber washers offer good compressibility and sealing characteristics and are commonly found in gasket-style and sealing applications where some compression under load is required.
Engineering Plastics
Engineering plastics provide structural performance in a non-metal form, combining dimensional stability, low friction, and mechanical strength for applications where metal is not appropriate.
Delrin® (acetal) offers excellent dimensional stability, low moisture absorption, low friction, and good strength. It is commonly found in mechanical assemblies, bearings, and precision components where a structural non-metal with consistent dimensional performance is required.
Phenolic is strong, heat-resistant, and electrically insulating. It is commonly found in electrical panels, switchgear, and high-temperature insulation applications.
Celcon and Nylatron offer enhanced properties for specific mechanical and tribological applications, similar to Delrin® and Nylon respectively but optimized for particular performance requirements.
High-Performance Films and Laminates
High-performance film and laminate materials are used in applications requiring extreme thermal stability, dielectric performance, or insulation at elevated temperatures.
Kapton (polyimide film) offers exceptional thermal stability and dielectric properties. It is commonly found in aerospace electronics, flexible circuits, and high-temperature electrical insulation applications.
Mylar (polyester film) provides good dimensional stability and dielectric properties. It is commonly found in electronics, capacitors, and general insulation applications.
Fiberglass offers a high strength-to-weight ratio with electrical insulation and heat resistance. It is commonly found in electrical enclosures, circuit board assemblies, and structural insulation applications.
Mica provides outstanding heat resistance and electrical insulation at elevated temperatures. It is commonly found in motor insulation, heating elements, and high-temperature electrical applications.
Material Selection by Operating Environment
The table below maps common operating environments to the washer materials most frequently associated with them. Use it as a starting point for material identification. Always verify the final selection against the specific requirements of your application with a qualified engineer.
| Operating Environment | Commonly Associated Materials | Key Performance Characteristics |
| Marine and Saltwater | Stainless Steel | Corrosion resistance in chloride-rich environments |
| Outdoor Exposure | 304 Stainless Steel, 316 Stainless Steel, Aluminum | Weather and moisture resistance |
| Electrical: Conductivity | Brass Alloy 260, Copper Alloy 110, Phosphor Bronze | High electrical and thermal conductivity, grounding |
| Electrical: Insulation | Nylon 6/6, PTFE, Fiber, Phenolic, Kapton | Non-conductive, dielectric properties, electrical isolation |
| Chemical Exposure | PTFE, Nylon 6/6, PVC | Chemical resistance, compatibility with process fluids |
| Lightweight Assemblies | Aluminum (Grades 1100, 3003, 5052, 6061), Nylon 6/6 | Weight reduction while maintaining adequate strength |
| General Industrial / High-Load | High Carbon Steel, Low Carbon Steel, 304 Stainless Steel | Strength, load-bearing capacity, cost-effectiveness |
| Precision / Mechanical | Delrin®, Nylatron, Celcon, Brass Alloy 260 | Dimensional stability, low friction, mechanical performance |
| Military and Defense | Per AN/NAS/MS specification: stainless steel, aluminum, specialty alloys | Specification compliance, material traceability, certification |
Editor's Note: The materials listed above reflect general industry patterns and are provided for informational reference only. Superior Washer & Gasket does not provide engineering or application-specific advice. Material selection for any application should be determined by a qualified engineer based on the specific requirements, operating conditions, and applicable standards of that application. Superior Washer & Gasket assumes no responsibility for the performance or suitability of any material in a specific application.
Custom Washer Materials
When a standard catalog material does not meet the requirements of an application, Superior Washer manufactures washers in customer-specified material grades. This includes specialty alloys, uncommon non-metals, and material combinations not available as standard stock items.
Custom material options include: Brass Alloy 260, Copper Alloy 110, Phosphor Bronze, all aluminum grades, all stainless steel grades, carbon steel, Nylon 6/6, PTFE, Delrin®, Phenolic, Celcon, Nylatron, PVC, Neoprene, Kapton, Mylar, Fiberglass, Mica, Polyethylene, Polypropylene, and Fiber.
Material certifications and traceability documentation are available for defense, aerospace, and regulated industry applications where documentation of material origin and compliance is required.
Choosing the Right Washer Material
Material selection is driven by the demands of the operating environment. Corrosion exposure, temperature range, electrical requirements, weight constraints, and specification compliance all factor into the right choice. No single material covers every application, which is why Superior Washer stocks an exceptionally broad range, from common stainless steel grades to specialty alloys, engineering plastics, and high-performance films.
The same material expertise that applies to flat washers extends across Superior Washer's full product range, including military-specification washers, spring washers, spacers, and shims.
Need a washer in a specific material or grade? Request a quote or contact our team.
Frequently Asked Questions
Below are answers to some of the most common questions about washer materials and grades.
What are the most common washer materials?
The most commonly used washer materials in industrial applications are stainless steel (grades 301, 302, 304, and 316), aluminum, brass, copper, carbon steel, and nylon. The right choice depends on the operating environment, load requirements, and any applicable specifications.
What is the difference between 304 and 316 stainless steel washers?
Grade 304 is the most common stainless steel grade and offers good corrosion resistance across a wide range of environments. Grade 316 contains molybdenum, which provides enhanced resistance to chloride corrosion. Grade 316 is commonly found in marine, saltwater, and chemically aggressive environments where 304 may not provide adequate protection.
Does Superior Washer stock Monel or Inconel washers?
No. Superior Washer does not currently stock or manufacture washers in Monel or Inconel. For applications requiring these alloys, contact our team to discuss alternative material options.
What is the difference between Nylon 6/6 and PTFE washers?
Nylon 6/6 and PTFE are both non-conductive, lightweight non-metal materials, but they serve different needs. Nylon 6/6 offers good mechanical strength, low friction, and broad chemical resistance, making it a general-purpose non-metal option. PTFE offers superior chemical resistance and extremely low friction, and is commonly found in more demanding chemical, pharmaceutical, and food processing environments.
What aluminum grades are flat washers available in?
Superior Washer stocks aluminum flat washers in grades 1100, 2024, 3003, 5052, and 6061. Each grade offers a different balance of strength, corrosion resistance, and formability for different application requirements.
Can washers be manufactured in specialty or customer-specified materials?
Yes. Superior Washer manufactures washers in a wide range of customer-specified material grades, including specialty alloys, non-metals, and materials not available as standard catalog items. Material certifications and traceability documentation are available for regulated applications.
What materials are used in military-specification washers?
Military-specification washers are manufactured to AN, NAS, and MS standards, which define the required material, dimensions, finish, and traceability for each specification. Materials commonly associated with mil-spec washers include stainless steel, aluminum, and specialty alloys, depending on the specific standard called out in the program documentation.
Does Superior Washer supply spring washers and spacers in the same materials?
Yes. Superior Washer stocks spring washers and spacers across a range of materials consistent with the flat washer product line. Contact our team for specific material availability by product type.
Where can I find information on washer types and sizes?
To discuss material requirements, request a quote.