Stainless Steel Flat Washers – Stanley Alloys
Introduction
Stanley Alloys is a leading manufacturer and supplier of 316 stainless steel flat washers in India, providing high-quality fastener solutions for industrial, marine, automotive, and construction applications. Stainless steel flat washers are fundamental mechanical components used across industries—they are thin, flat, circular discs with a central hole designed to fit around bolts, screws, or threaded fasteners. Their primary purpose is to distribute the load of a fastener evenly, preventing surface damage, reducing wear, and enhancing the stability of assembled components.
Significance & Role
- Load Distribution: Spread the force exerted by the fastener over a larger surface area, preventing cracking, deformation, or surface indentation.
- Corrosion Resistance: Made from stainless steel, these washers resist rust, oxidation, and chemical degradation, ensuring longevity even in harsh environments.
- Vibration Reduction: Act as a cushion to minimize loosening caused by vibration or dynamic forces.
- Surface Protection: Prevent direct contact between fasteners and softer surfaces, reducing scratches, dents, and other surface damage.
Material Composition
- 316 Stainless Steel: Superior corrosion resistance; ideal for marine, chemical, and outdoor applications.
- 304 Stainless Steel: Excellent corrosion resistance for general-purpose applications.
- 430 Stainless Steel: Magnetic and cost-effective for less corrosive environments.
Standards & Specifications
Stanley Alloys’ washers comply with ISO 7089, an international standard formulated by the International Organization for Standardization (ISO), defining specifications for plain (flat) washers:
- Material: Stainless steel, including 316 grade for maximum corrosion resistance
- Hardness Range: 200 HV – 300 HV
- Nominal Sizes: Suitable for thread diameters from 1.6 mm to 64 mm
- Applications: General fastening, structural assemblies, marine, and industrial equipment
- Other standards: ISO 7090, DIN 125 / 9021, ANSI B18.22.1, SAE, and USS
Types of Flat Washers
- Flat vs. Fender Washers: Flat Washer distributes load evenly; Fender Washer has a larger outer diameter for wider load distribution.
- Type A vs. Type B: Type A for general applications; Type B for strict dimensional accuracy.
- SAE vs. USS: SAE is smaller diameter for automotive; USS is larger for industrial use.
- Square Flat Washers: Ideal for timber, concrete floors, heavy-duty assemblies; reduces friction, heat, may provide insulation.
Applications
- Construction & Infrastructure: Bridges, buildings, heavy machinery
- Marine & Offshore: Ships, docks, offshore platforms
- Automotive & Aerospace: Engines, chassis, aerospace components
- Industrial Machinery: Pumps, valves, pipelines, chemical processing units
- Electronics & Electrical: Panels and equipment requiring insulation and surface protection
Why Choose Stanley Alloys?
- Premium Quality: 316 stainless steel washers with superior corrosion resistance
- Global Standards: ISO 7089, ANSI, SAE, USS, DIN compliance
- Precision Manufacturing: Type A and Type B washers for diverse applications
- Versatile Applications: Marine, automotive, construction, and industrial machinery
- Custom Solutions: Tailored sizes and thicknesses to meet client-specific requirements
Maintenance & Care
- Regular Inspection: Check washers for signs of wear, corrosion, or deformation, especially in marine or chemical environments.
- Proper Cleaning: Use mild detergents or stainless steel cleaners; avoid harsh chemicals that can damage surfaces.
- Correct Installation: Ensure washers are used with compatible bolts and nuts; do not overtighten, which can deform or crack them.
- Storage: Keep in dry, cool conditions; separate from high-humidity or corrosive materials.
- Replacement Guidelines: Replace washers that show visible wear, pitting, or corrosion to maintain assembly integrity.
Conclusion
Stainless steel flat washers from Stanley Alloys are more than simple components. They are critical for ensuring mechanical integrity, durability, and reliable performance in any application. With the right material, grade, and standard, these washers provide optimal load distribution, corrosion resistance, and surface protection, making them indispensable in modern engineering and industrial operations.
Flat Washers Material and Grades
Stanley Alloys – High-Performance Washers
Stanley Alloys is a premier manufacturer and supplier of high-performance flat washers in India. We offer a comprehensive range of washers manufactured from diverse materials and grades, engineered for superior strength, durability, and corrosion resistance. Our washers are suitable for industrial, marine, automotive, construction, and specialized engineering applications.
1. Carbon Steel Flat Washers
- Grades & Specifications: AISI 1018, 1045, 1117, 12L14, 1215; ASTM A36, A29, A108, A549; SAE J429, ASTM A307 (Grades A/B/C)
- Properties: Excellent mechanical strength, moderate corrosion resistance
- Applications: Structural assemblies, machinery, general-purpose fastening
2. High-Tensile Flat Washers
- Grades: 4.6, 4.8, 5.8, 8.8, 9.8, 10.9, 12.9
- Applications: Heavy machinery, automotive, construction, high torque bolted connections
3. Stainless Steel Flat Washers
- Austenitic: SS 201, 303, 304, 304L, 316, 316L, 316H, 317L, 321, 304H, 310
- Martensitic: SS 410, 420, 440, 630 (17-4)
- Duplex & Super Duplex: Duplex 2205, Super Duplex 2507
- Special Grades & Coatings: 904L, 18-8 SS, Black SS, A2-70, A2-80, A4-70, A4-80, A193 B8C (347), A193 B8T (321), A193 B6 (410)
- Applications: Marine, chemical plants, offshore structures, food processing, aerospace
4. Martensitic & Precipitation Hardening Stainless Steel Washers
- Grades: 15-5 PH, 17-4 PH, 17-7 PH
- Properties: High strength, hardness, corrosion resistance
- Applications: Aerospace, tooling, high-performance machinery
5. ASTM Standard Flat Washers
- ASTM A193: B6, B7, B7m, B8T, B8, B8 Class 1/2, B8M Class 2, B16, B6X
- ASTM A449: Type 1 – Carbon steel, alloy steel, carbon-boron, alloy-boron
- ASTM F593: 303, 304, 304L, 305, 384, XM1, 316, 316L, 321, 347, 430, 410, 416, 431, 630 (17-4)
- Other Standards: A320, A325, A36, A540, A563, A354, A490, A593, F593C/D/G
6. Alloy Steel & High-Performance Washers
- Alloy Steel: AISI 4140, 4130, ASTM A193 B7/B8/B8M
- Spring Steel: C55S, C60S, C67S, C75S, C100S, 51CrV4, 80CrV2
- Heavy Hex Structural Washers: ASTM F3125, including A325, A490, F1852, F2280
7. Non-Ferrous Washers
- Brass: H59, H62, C36000, C37700, C38500, C27200
- Aluminum: Al6061, Al6063, 5052, 2017, 7075
- Titanium: ASTM B348 / ASME SB348, Grades 1, 2, 4, 5, 7
- Copper: T1, T2, C10100–C33000 series, TP1, TP2
- Copper-Nickel: ASTM/ASME SB151, 70/30 & 90/10 alloys
8. Superalloys & Specialty Materials
- Inconel: B166/SB166, 600, 601, 625, 718, 690, X750
- Hastelloy: C276, C22, C4, C2000
- Incoloy: 800, 800H, 800HT, 825, 925, ASTM A453/A638/A286 Grade 660
- Monel & Nickel: Monel 400/500, Nickel 200/201/205/205LC
- Alloy 20: ASTM B462 / ASME SB462
- 254 SMO & Nimonic: SMO 254/6Mo, Nimonic 75/80A/90
- Phosphor & Aluminum Bronze: PB102, PB104, CA104, DEF STAN 02-833/834
- Other Materials: Tin Bronze, Lead Bronze, Stellite, Molybdenum, Tantalum, Zirconium, Austenitic Steel, Chromium Vanadium Steel, Super Austenitic Steel, Weathering Steel
Why Stanley Alloys?
Stanley Alloys provides precision-engineered flat washers in every material grade and standard, ensuring durability, performance, and reliability for all industrial and engineering applications.
AISI 410 Stainless Steel Flat Washers
Dimensions & Specifications | Stanley Alloys
Stanley Alloys offers precision-engineered AISI 410 stainless steel flat washers in a comprehensive range of sizes and dimensions, suitable for industrial, construction, automotive, and structural applications. Our washers are manufactured to meet global standards and are designed to provide optimal load distribution, surface protection, and corrosion resistance in demanding environments.
These flat washers are available in metric thread sizes ranging from M1.6 to M160, with carefully controlled inner diameter, outer diameter, and thickness tolerances to ensure a perfect fit for every bolted assembly.
Key Dimension Parameters
Each AISI 410 flat washer is defined by the following dimensions:
| Parameter | Description |
|---|---|
| d1 (Clearance Hole Diameter) | Minimum and maximum inner diameter of the washer hole, designed to fit over the bolt or screw thread. |
| d2 (Outside Diameter) | Minimum and maximum external diameter of the washer, ensuring proper load distribution. |
| h (Thickness) | Minimum and maximum thickness of the washer for strength and stability. |
| d3 | Optional reference for certain dimensional standards or tolerances. |
Standard Metric Dimensions – M1.6 to M28
| Thread Size | d1 Min–Max (mm) | d2 Min–Max (mm) | h Min–Max (mm) | d3 Min (mm) |
|---|---|---|---|---|
| M1.6 | 1.7–1.84 | 4–3.7 | 0.25–0.35 | 1.8–2 |
| M2 | 2.2–2.34 | 5–4.7 | 0.25–0.35 | 2.4–2.6 |
| M3 | 3.2–3.38 | 7–6.64 | 0.45–0.55 | 3.4–3.6 |
| M4 | 4.3–4.48 | 9–8.64 | 0.7–0.9 | 4.5–4.7 |
| M6 | 6.4–6.62 | 12–11.57 | 1.4–1.8 | 6.6–6.8 |
| M8 | 8.4–8.62 | 16–15.57 | 1.4–1.8 | 9–9.2 |
| M10 | 10.5–10.77 | 20–19.48 | 1.8–2.2 | 11–11.2 |
| M12 | 13–13.27 | 24–23.48 | 2.3–2.7 | 13.5–13.7 |
| M16 | 17–17.27 | 30–29.48 | 2.7–3.3 | 17.5–17.7 |
| M20 | 21–21.33 | 37–36.38 | 2.7–3.3 | 22–22.4 |
| M24 | 25–25.33 | 44–43.38 | 3.7–4.3 | 26–26.4 |
| M28 | 29–29.33 | 50–49.38 | 3.7–4.3 | 31–31.4 |
Extended Metric Sizes – M30 to M160
| Thread Size | d1 Min–Max (mm) | d2 Min–Max (mm) | h Min–Max (mm) | d3 Min (mm) |
|---|---|---|---|---|
| M30 | 31–31.39 | 56–55.26 | 3.7–4.3 | 33–33.4 |
| M40 | 41–41.62 | 72–70.8 | 5.4–6.6 | 43–43.6 |
| M50 | 52–52.74 | 92–90.6 | 7–9 | 54–54.6 |
| M60 | 62–62.74 | 110–108.6 | 8–10 | 66–67 |
| M80 | 82–82.87 | 140–138.4 | 10.8–13.2 | 86–87 |
| M100 | 104–104.87 | 175–173.4 | 12.8–15.2 | 107–108 |
| M120 | 124–125 | 210–208.15 | 14.8–17.2 | 127–128 |
| M150 | 155–156 | 250–248.15 | 16.8–19.2 | 158–159 |
| M160 | 165–166 | 250–248.15 | 16.8–19.2 | 168–169 |
Why Stanley Alloys AISI 410 Washers Are Trusted
Stainless Steel 304 Flat Washers
Coatings & Surface Treatments | Stanley Alloys
At Stanley Alloys, we provide high-quality 304 stainless steel flat washers with advanced surface treatments and coatings to enhance durability, corrosion resistance, and aesthetic finish. Our washers are engineered to perform in harsh environments, from industrial machinery to marine and chemical applications.
1. Passivation and Self-Colour Treatments
- Passivated Self-Colour: Removes free iron from the surface to prevent rust and improve corrosion resistance naturally.
- Bright Zinc Plating (BZP): Provides a reflective finish while enhancing corrosion protection.
- Polish & Buffing: Creates a smooth, aesthetically appealing surface that reduces friction and prevents surface scratches.
2. Chemical and Coating Treatments
- Teflon Coating (PTFE): Non-stick, chemical-resistant coating that reduces friction and protects against corrosion.
- Xylon Coating: High-performance industrial coating for corrosion and wear resistance.
- Phosphate Coating: Improves adhesion of paints and lubricants while providing corrosion protection.
- Dacromet & Sherardized Coatings: Zinc-iron or zinc-nickel-based coatings offering long-term corrosion resistance in industrial environments.
3. Metal Coatings and Electroplating
- Zinc Coatings: Hot-dip galvanizing, zinc white, zinc yellow, zinc black, and zinc blue for corrosion protection.
- Nickel and Chromium Plating: Electroplated nickel (Ni) and chromium (Cr) layers for wear resistance and aesthetic finish.
- Tin, Copper, and Silver Plating: Specialized coatings for electrical conductivity or decorative applications.
- Cadmium Coating: Provides excellent corrosion resistance in marine and aerospace environments.
4. Mechanical and Surface Finishing Techniques
- Black Oxide Coating: Enhances surface durability and provides a sleek black finish.
- Sand Blasting: Cleans and textures the surface for better coating adhesion.
- Anodizing: For aluminum and compatible stainless surfaces, improving corrosion resistance and appearance.
- Heat Treatment / Heat Disposing: Increases mechanical strength and stress resistance.
5. Protective and Industrial Coatings
- Rust Preventive Oil: Temporary protection during storage and shipping.
- Mechanically Applied Coatings: Durable industrial coatings for specialized environments.
- Hot Dip Galvanized (HDG): Provides thick, long-lasting corrosion protection for outdoor and marine applications.
Why Stanley Alloys Surface Treatments Stand Out
Conclusion
Stanley Alloys’ 304 stainless steel flat washers are available with a wide range of coatings and surface treatments to meet diverse industrial, structural, and marine requirements. From passivation and polishing to electroplating and hot-dip galvanizing, our washers deliver durability, corrosion resistance, and superior performance in every application.
Stanley Alloys – Flat Washers Weight & Dimension Charts
High-strength and precision-engineered flat washers for industrial and structural applications.
Stanley Alloys offers a comprehensive range of high-strength and precision-engineered flat washers, including ASTM A320 L7, SAE, USS, and structural washers. Our washers are manufactured to exacting standards, ensuring accurate dimensions, consistent weight, and reliable performance across all industrial and structural applications.
These charts help engineers, procurement teams, and designers quickly select the right washer type, size, and weight for any assembly, ensuring optimal load distribution, safety, and compliance.
1. SAE Flat Washers – Weight Chart
| Bolt Size | Inner Diameter (ID) | Outer Diameter (OD) | Thickness (Th) | Approx Lbs per 1000 pcs | Approx Pcs per 50 lb Carton | Approx Pcs per LB |
|---|---|---|---|---|---|---|
| #6 | 5/32 | 3/8 | .036/.065 | 1.26 | 39,500 | 790 |
| #8 | 3/16 | 7/16 | .036/.065 | 1.7 | 29,500 | 585 |
| #10 | 7/32 | 1/2 | .036/.065 | 2.3 | 22,750 | 435 |
| #12 | 1/4 | 9/16 | .051/.080 | 3.4 | 14,700 | 280 |
| 1/4 | 9/32 | 5/8 | .051/.080 | 4.5 | 11,100 | 222 |
| 5/16 | 11/32 | 11/16 | .051/.080 | 5.2 | 9,750 | 192 |
| 3/8 | 13/32 | 13/16 | .051/.080 | 7.2 | 7,000 | 140 |
| 7/16 | 15/32 | 59/64 | .051/.080 | 9.5 | 5,500 | 105 |
| 1/2 | 17/32 | 1 1/16 | .074/.121 | 18.3 | 2,800 | 55 |
| 9/16 | 19/32 | 1 5/32 | .074/.121 | 23.4 | 2,250 | 43 |
| 5/8 | 21/32 | 1 5/16 | .074/.121 | 27.7 | 1,850 | 36 |
| 3/4 | 13/16 | 1 15/32 | .108/.160 | 47.4 | 1,050 | 21 |
| 7/8 | 15/16 | 1 3/4 | .108/.160 | 63 | 775 | 16 |
| 1 | 1 1/16 | 2 | .108/.160 | 83 | 585 | 12 |
| 1 1/8 | 1 1/4 | 2 1/4 | .108/.160 | 109 | 460 | 9.2 |
| 1 1/4 | 1 3/8 | 2 1/2 | .136/.192 | 160 | 335 | 6.3 |
| 1 3/8 | 1 1/2 | 2 3/4 | .136/.213 | 190 | 275 | 5.25 |
| 1 1/2 | 1 5/8 | 3 | .153/.213 | 240 | 230 | 4.25 |
2. Weight of 5/16" Thick Hardened Structural Washers
| Bolt Size | Outside Diameter | Inside Diameter | Thickness | Approx Lbs per 1000 pcs | Approx Pcs per Carton |
|---|---|---|---|---|---|
| 1 | 2.000 | 1.063 | .312 | 196 | 250 |
| 1 1/8 | 2.250 | 1.188 | .312 | 252 | 200 |
| 1 1/4 | 2.500 | 1.375 | .312 | 303 | 175 |
| 1 1/2 | 3.000 | 1.625 | .312 | 442 | 80 |
3. Beveled Structural Washers – Weight Chart
| Bolt Size | Outside Diameter | Slope | Approx Lbs per 1000 pcs | Approx Pcs per Carton |
|---|---|---|---|---|
| 1/2 | 1.750 | 16-2/3% | 251 | 200 |
| 5/8 | 1.750 | 16-2/3% | 237 | 250 |
| 3/4 | 1.750 | 16-2/3% | 224 | 250 |
| 7/8 | 1.750 | 16-2/3% | 209 | 250 |
| 1 | 1.750 | 16-2/3% | 181 | 250 |
Key Features of Stanley Alloys Flat Washers
Stanley Alloys – Flat Washers Detailed Charts
12.9 Grade Flat Washers – SAE Sizes
| Bolt Size | Outside Diameter | Inside Diameter | Thickness | Approx Lbs per M Pcs | Approx Pcs per Carton |
|---|---|---|---|---|---|
| #6 | .375 | .156 | .036/.065 | 1.26 | 39,500 |
| #8 | .438 | .188 | .036/.065 | 1.7 | 29,500 |
| #10 | .500 | .219 | .036/.065 | 2.2 | 22,750 |
| #12 | .563 | .250 | .051/.080 | 3.4 | 14,700 |
| 1/4 | .625 | .281 | .051/.080 | 4.5 | 11,100 |
| 5/16 | .688 | .344 | .051/.080 | 5.1 | 9,750 |
| 3/8 | .813 | .406 | .051/.080 | 7.1 | 7,000 |
| 7/16 | .922 | .469 | .051/.080 | 9.1 | 5,500 |
| 1/2 | 1.063 | .531 | .074/.121 | 17.8 | 2,800 |
12.9 Grade Flat Washers – USS Sizes
| Bolt Size | Outside Diameter | Inside Diameter | Thickness | Approx Lbs per M Pcs | Approx Pcs per Carton |
|---|---|---|---|---|---|
| 3/16 | .563 | .250 | .036/.065 | 2.8 | 18,050 |
| 1/4 | .734 | .313 | .051/.080 | 6.7 | 7,450 |
| 5/16 | .875 | .375 | .064/.104 | 11.5 | 4,350 |
| 3/8 | 1.000 | .438 | .064/.104 | 14.9 | 3,350 |
| 7/16 | 1.250 | .500 | .064/.104 | 22 | |
| 1/2 | 1.375 | .563 | .086/.132 | 38.5 | 1,300 |
| 9/16 | 1.469 | .625 | .086/.132 | 45.5 | 1,100 |
| 5/8 | 1.750 | .688 | .108/.160 | 77 | 650 |
| 3/4 | 2.000 | .813 | .122/.177 | 110 | 455 |
| 7/8 | 2.250 | .938 | .136/.192 | 154 | 325 |
316 Stainless Steel Flat Washers
Specifications, Standards & Compliance – Stanley Alloys
Stanley Alloys is a trusted supplier and exporter of high-quality stainless steel flat washers in India, including Grade 10.9 Flat Washers and ASTM F844 Extra Thick Heavy Duty Flat Washers. Our washers are engineered for strength, durability, and precision, meeting global industrial standards for diverse applications.
Standards & Compliance
| Standard Type | Applicable Standards |
|---|---|
| ANSI – American Standard | ANSI B18.22.1 |
| DIN – German Standard | DIN 125, DIN 127, DIN 9021, DIN 127b, DIN 125-1, DIN 433, DIN 126, DIN 6340, DIN 6916, DIN 125a |
| ISO Standard | ISO 7089 – SS 316 A4-80 Flat Washers |
| Other International Standards | IS, ASTM, JIS, GB, ASME, BS, UNI, CSN, EU, IFI, PN |
Additional Standard References:
- American ASME
- Indian IS
- International ISO
- American SAE
- German DIN
- Spanish CSN
- British BS
- Italian UNI
- Polish PN
- European EU
Material & Size Specifications
| Material / Grade | Diameter Range | Length / Thickness |
|---|---|---|
| Stainless Steel 304 | M10 – M110 (Metric) | 12 – 1200 mm |
| AISI 410 Stainless Steel | 1/2" – 4.0" (Inch) | 1/2" – 52" |
Threads Compatibility
- Unified National Coarse (UNC)
- Unified National Fine (UNF)
- Unified National Extra Fine (UNEF)
- UNJC, UNJF, UNK, UNR, Constant-pitch threads
Common 8.8 Grade Standard Sizes
M2, M2.5, M3, M4, M5, M6, M8, M10, M12, M14, M16, M20, M24, M30, M36, up to M160
Manufacturing & Production Process
- Cold Forging: M2 – M24 washers
- Hot Forging: M2 – M24 washers
- Machining & CNC Processing: M24 – M100 washers, and customized sizes
- Threading – Precision thread integration
- Heat Treatment – Hardening for durability
- Plating & Coating – Zinc or other coatings for additional corrosion resistance
- Baking & QA – Final quality inspection and performance checks
- Packaging & Shipping – Safe and secure for international transit
Plating & Coating Specifications
| Plating / Coating Standard | Type |
|---|---|
| ASTM A153 | Hot-dip Zinc Coating |
| ASTM B695 | Zinc Coating |
| ASTM F1941 | Electrodeposited Zinc Plating |
| ASTM F2329 | Hot-dip Zinc Coating |
Packing & Delivery
- Packing Options: Wooden pallets, cartons, or small boxes
- Carton Size: 36 × 24 × 16 cm or 36 × 24 × 12 cm (customizable)
- Pallet Size: Standard Euro Pallet – 110 × 80 × 90 cm
- Delivery Time: 7–15 working days (dependent on order quantity)
- Port of Dispatch: Mumbai or Kalamboli, Maharashtra, India
Certificates & Documentation
- Manufacturer Test Certificate (MTC): EN 10204 / 3.1
- Preferred Drawing Formats: JPEG, PDF, CAD, STP, IGS
Conclusion
Stanley Alloys is committed to delivering high-performance stainless steel flat washers with precision engineering, global standard compliance, and tailored solutions for every industrial need.
A193 Grade B8 Class 2 Flat Washers
Testing & Measuring Equipment – Stanley Alloys
At Stanley Alloys, quality and precision are our top priorities. Every flat washer undergoes rigorous testing and measurement to ensure compliance with international standards, guaranteeing reliability in industrial, marine, and structural applications.
Precision Measuring Instruments
- Micrometer – Accurate measurement of washer thickness, diameter, and dimensional tolerances.
- Thread Gauge – Ensures threads match specifications precisely for proper fit and assembly.
- Smooth Plug Gauge – Checks the clearance hole diameter for compliance with standards.
- Roughness Tester – Measures surface finish and texture to maintain smoothness and quality.
- Image Measuring Instrument – Captures detailed images for dimensional verification and quality assurance.
- Coordinate Measuring Machine (CMM) – Performs precise 3D measurement of complex washer geometries.
- Routine Inspection of Calipers – Ensures calipers are accurate for day-to-day measurements and quality control.
Why Stanley Alloys Testing is Superior
- High Accuracy: Every instrument ensures washers meet exact tolerances.
- Compliance: Fully aligns with ASTM, ISO, and international standards.
- Reliability: Guarantees flat washers can withstand mechanical stress in critical applications.
- Advanced Technology: Incorporates the latest CMM and image measurement systems for modern inspection.