Stainless Steel 304L Washers are precision-engineered fastening components designed to distribute load, reduce surface wear, and maintain joint stability in bolted assemblies exposed to corrosive or high-moisture environments. Manufactured from low-carbon austenitic stainless steel (304L grade), these washers comply with widely recognized standards such as DIN 125, ISO 7089, and ASTM A240, ensuring dimensional accuracy and reliable mechanical performance across critical applications.

These washers are extensively used in chemical processing plants, marine equipment, construction frameworks, and heavy machinery assemblies where corrosion resistance and long-term structural integrity are essential. The low carbon content in 304L enhances weldability and reduces carbide precipitation, making it suitable for welded structures and continuous load environments.
KK Fasteners supplies Stainless Steel 304L Washers to global OEMs and industrial distributors, ensuring material traceability and strict dimensional control for every production batch. For engineers and procurement teams, these washers deliver a dependable balance of corrosion resistance, mechanical stability, and international standard compliance—making them a preferred choice in demanding industrial environments.
| Parameter | Specification |
|---|---|
| Material | Stainless Steel 304L (Austenitic, Low Carbon) |
| Equivalent Grades | AISI 304L, UNS S30403, EN 1.4307 |
| Size Range | M3 to M64 (Metric), 1/8" to 2.5" (Imperial) |
| Thread Type Compatibility | Metric (Coarse/Fine), UNC, UNF |
| Standards | DIN 125, DIN 9021, ISO 7089, ASTM A240, BS 4320 |
| Surface Finish | Plain, Passivated, Polished, Anti-corrosion Coated |
| Type Variants | Flat Washers, Spring Washers (supporting variants), Fender Washers |
| Hardness | ≤ 95 HRB (Typical) |
| Tensile Strength | 485 MPa (Minimum) |
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 304L | min. | – | – | – | – | – | 18.0 | – | 8.0 | – |
| max. | 0.08 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 10.5 | 0.10 | ||
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| 304L | 515 | 205 | 40 | 92 | 201 |
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 304L | S30400 | 304S31 | 58E | 1.4301 | X5CrNi18-10 | 2332 | SUS 304L |
Bolt Size
|
USS
|
SAE
|
||||
OD (in.)
|
ID (in.)
|
Thickness
|
OD (in.)
|
ID (in.)
|
Thickness
|
|
1/8 (#6)
|
-
|
-
|
-
|
0.375
|
0.156
|
.036/.065
|
5/32 (#8)
|
-
|
-
|
-
|
0.438
|
0.188
|
.036/.065
|
3/16 (#10)
|
0.560
|
0.250
|
.036/.065
|
0.500
|
0.220
|
.036/.065
|
7/32 (#12)
|
-
|
-
|
-
|
0.562
|
0.250
|
.051/.080
|
1/4 (#14)
|
0.734
|
0.312
|
.051/.080
|
0.625
|
0.281
|
.051/.080
|
5/16
|
0.875
|
0.375
|
.064/.104
|
0.688
|
0.344
|
.051/.080
|
3/8
|
1.000
|
0.438
|
.064/.104
|
0.812
|
0.406
|
.051/.080
|
7/16
|
1.250
|
0.500
|
.064/.104
|
0.922
|
0.469
|
.051/.080
|
1/2
|
1.375
|
0.562
|
.086/.132
|
1.062
|
0.531
|
.074/.121
|
9/16
|
1.469
|
0.625
|
.086/.132
|
1.156
|
0.594
|
.074/.121
|
5/8
|
1.750
|
0.688
|
.108/.160
|
1.312
|
0.656
|
.074/.121
|
3/4
|
2.000
|
0.812
|
.122/.177
|
1.469
|
0.812
|
.108/.160
|
7/8
|
2.250
|
0.938
|
.136/.192
|
1.750
|
0.938
|
.108/.160
|
1
|
2.500
|
1.062
|
.136/.192
|
2.000
|
1.062
|
.108/.160
|
1 1/8
|
2.750
|
1.250
|
.136/.192
|
2.250
|
1.250
|
.108/.160
|
1 1/4
|
3.000
|
1.375
|
.136/.192
|
2.500
|
1.375
|
.136/.192
|
1 3/8
|
3.250
|
1.500
|
.153/.213
|
2.750
|
1.500
|
.136/.213
|
1 1/2
|
3.500
|
1.625
|
.153/.213
|
3.000
|
1.625
|
.153/.213
|
1 5/8
|
3.750
|
1.750
|
.153/.213
|
-
|
-
|
-
|
1 3/4
|
4.000
|
1.875
|
.153/.213
|
-
|
-
|
-
|
1 7/8
|
4.250
|
2.000
|
.153/.213
|
-
|
-
|
-
|
2
|
4.500
|
2.125
|
.153/.213
|
-
|
-
|
-
|
2 1/4
|
4.750
|
2.375
|
.320/.248
|
-
|
-
|
-
|
2 1/2
|
5.000
|
2.625
|
.210/.280
|
-
|
-
|
-
|
2 3/4
|
5.250
|
2.875
|
.228/.410S
|
-
|
-
|
-
|
3
|
5.500
|
3.125
|
.249/.327
|
-
|
-
|
-
|
Size |
USS |
SAE |
||||
|---|---|---|---|---|---|---|
Inside Diameter (A) |
Outside Diameter (B) |
Thickness (C) |
Inside Diameter (A) |
Outside Diameter (B) |
Thickness (C) |
|
#2 |
- |
- |
- |
3/32" |
1/4" |
0.020" |
#4 |
- |
- |
- |
1/8" |
5/16" |
0.032" |
#6 |
- |
- |
- |
5/32" |
3/8" |
0.049" |
#8 |
- |
- |
- |
3/16" |
7/16" |
0.049" |
#10 |
- |
- |
- |
7/32" |
1/2" |
0.049" |
#12 |
- |
- |
- |
1/4" |
9/16" |
0.065" |
1/4" |
5/16" |
0.734" |
0.065" |
9/32" |
5/8" |
0.065" |
5/16" |
3/8" |
7/8" |
0.083" |
11/32" |
11/16" |
0.065" |
3/8" |
7/16" |
1" |
0.083" |
13/32" |
13/16" |
0.065" |
7/16" |
1/2" |
1-1/4" |
0.083" |
15/32" |
15/16" |
0.065" |
1/2" |
9/16" |
1-3/8" |
0.109" |
17/32" |
1-1/16" |
0.095" |
9/16" |
5/8" |
1-15/32" |
0.109" |
19/32" |
1-5/32" |
0.095" |
5/8" |
11/16" |
1-3/4" |
0.134" |
21/32" |
1-5/16" |
0.095" |
3/4" |
13/16" |
2" |
0.148" |
13/16" |
1-15/32" |
0.134" |
7/8" |
15/16" |
2-1/4" |
0.165" |
15/16" |
1-3/4" |
0.134" |
1" |
1-1/16" |
2-1/2" |
0.165" |
1-1/16" |
2" |
0.134" |
1-1/8" |
1-1/4" |
2-3/4" |
0.165" |
- |
- |
- |
1-1/4" |
1-3/8" |
3" |
0.165" |
- |
- |
- |
1-3/8" |
1-1/2" |
3-1/4" |
0.180" |
- |
- |
- |
1-1/2" |
1-5/8" |
3-1/2" |
0.180" |
- |
- |
- |
1-5/8" |
1-3/4" |
3-3/4" |
0.180" |
- |
- |
- |
1-3/4" |
1-7/8" |
4" |
0.180" |
- |
- |
- |
2" |
2-1/8" |
4-1/2" |
0.213" |
- |
- |
- |
Stainless Steel 304L Washers are used wherever controlled load distribution, vibration resistance, and corrosion protection are required in bolted assemblies across industrial systems.
Stainless Steel 304L Washers are manufactured using precision stamping and cold forging techniques to ensure consistent geometry and surface quality. The production process begins with stainless steel coil selection, followed by blanking, forming, and edge finishing under controlled conditions. Each batch undergoes dimensional calibration to meet DIN and ISO tolerance requirements.
Quality control includes hardness testing, tensile verification, and surface inspection to ensure defect-free output. Passivation treatment is applied to enhance corrosion resistance by strengthening the chromium oxide layer. KK Fasteners maintains strict lot traceability and inspection records for every shipment, ensuring compliance with ISO 9001:2015 quality systems along with RoHS and REACH requirements for global markets.

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Stainless Steel 304L Washers are flat circular components used in bolted assemblies to distribute load, reduce surface damage, and improve joint stability. Made from low-carbon austenitic stainless steel, they offer strong corrosion resistance and are widely used in chemical, marine, and construction industries where durability and long service life are required.
The key difference is carbon content. 304L has lower carbon than 304, which reduces carbide precipitation during welding and improves corrosion resistance in welded structures. This makes 304L more suitable for applications exposed to moisture, chemicals, and continuous stress conditions.
These washers are commonly manufactured according to DIN 125, DIN 9021, ISO 7089, ASTM A240, and BS 4320 standards. These ensure proper dimensional accuracy, mechanical strength, and global compatibility in industrial fastening systems.
Selection depends on environmental conditions, load type, and material compatibility. 304L is ideal for general corrosion resistance and welded assemblies, while 316 is better for high chloride or marine exposure. Engineers should also consider bolt grade and compliance with international standards.
Choose a supplier with ISO certification, material traceability, and proven export experience. Reliable manufacturers provide test certificates, consistent quality control, and compliance with DIN/ISO standards. KK Fasteners supplies globally with documented inspection and traceability for industrial buyers.
Stainless Steel 304L Washers deliver dependable performance in corrosion-prone and high-load industrial environments where precision and compliance matter. With controlled manufacturing and global export capability, KK Fasteners ensures consistent quality backed by traceable production standards. For technical specifications, bulk pricing, or custom dimensions, connect with the engineering team at KK Fasteners to request a detailed quotation or project-specific support.