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Incoloy 925 washers are precipitation-hardened nickel-iron-chromium alloy components designed for extreme corrosion resistance and high mechanical strength in demanding environments. These washers are widely used in offshore oil & gas systems, marine engineering, chemical processing units, and high-pressure valve assemblies where conventional stainless steel fasteners fail due to chloride attack or stress corrosion cracking.
Manufactured to meet stringent standards such as ASTM B805 and UNS N09925 material classification, Incoloy 925 washers provide a reliable load distribution surface while maintaining structural integrity under elevated temperatures and aggressive media exposure. Their controlled chemistry ensures resistance against pitting, crevice corrosion, and sour gas environments containing hydrogen sulfide (H₂S).
KK Fasteners supplies engineered Incoloy 925 washers to global industrial clients with full material traceability, dimensional accuracy, and batch-level inspection documentation for critical applications.
| Parameter | Specification |
|---|---|
| Material | Incoloy 925 (UNS N09925) |
| Grade Condition | Solution annealed + precipitation hardened |
| Size Range | M3 to M100 / 1/8" to 4" |
| Standards | ASTM B805, ASME SB805, ISO 887 |
| Thread Compatibility | Metric (M), UNC, UNF |
| Hardness | 32–38 HRC (aged condition) |
| Tensile Strength | 900–1200 MPa |
| Surface Finish | Pickled, Passivated, Bright Polished |
| Washer Types | Flat washer, heavy duty washer, spring washer (custom variants) |
| Coating Options | Anti-galling coating, PTFE coating (on request) |
| Grade | C | Mn | Si | S | Cu | Fe | Ni | Cr | Al | Ti |
| 925 | 0.05 max | 1.00 max | 0.5 max | 0.03 max | 1.50 – 3.00 | 22.00 min | 38.00 – 46.00 | 19.50 – 23.50 | 0.02 max | 0.06 – 1.20 |
| Element | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 925 | 8.14 g/cm3 | 1400 °C (2550 °F) | Psi – 80,000 , MPa – 550 | Psi – 32,000 , MPa – 220 | 30 % |
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN | OR |
| Incoloy 925 | 2.4858 | N08925 | NCF 925 | NA 16 | ЭП703 | NFE30C20DUM | NiCr21Mo | XH38BT |
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" |
- |
- |
- |
Incoloy 925 washers are used wherever mechanical fastening must survive corrosive, high-pressure, or high-temperature environments. They are especially critical in industries where failure is not an option.
Incoloy 925 washers are manufactured using precision cold forging followed by controlled heat treatment to achieve precipitation hardening. This process ensures uniform grain structure and enhanced mechanical strength. CNC finishing is used to maintain tight dimensional tolerances, especially for critical sealing surfaces in high-pressure assemblies.
Each batch undergoes hardness testing, tensile validation, and dimensional inspection using calibrated gauges. Surface finish is verified for passivation quality and defect-free geometry. Traceability is maintained through heat number marking and batch documentation. KK Fasteners integrates ISO 9001:2015 quality systems along with RoHS and REACH compliance checks to ensure global acceptance across regulated industries.
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Incoloy 925 washers are high-strength nickel alloy fasteners designed for extreme corrosion resistance and mechanical stability. They are used to distribute load in bolted joints in offshore, marine, chemical, and oil & gas applications where standard stainless steel washers may fail.
Its nickel-iron-chromium base with molybdenum, copper, and titanium provides excellent resistance to pitting, crevice corrosion, and hydrogen sulfide (H₂S) stress corrosion cracking, especially in seawater and sour gas conditions.
These washers are typically manufactured in compliance with ASTM B805 and ASME SB805 standards, along with ISO and DIN dimensional standards to ensure global interchangeability and engineering reliability
They are widely used in offshore platforms, marine structures, chemical plants, refineries, power generation systems, and desalination units where corrosion resistance and long-term load stability are critical.
Look for ISO-certified manufacturers with material traceability, test certificates, controlled production processes, and proven export capability. KK Fasteners supplies certified Incoloy 925 washers with full inspection documentation for global projects.
ncoloy 925 washers are engineered for environments where corrosion failure is not an option, delivering long-term reliability under extreme conditions. With precision manufacturing, full traceability, and export-ready documentation, KK Fasteners supports global procurement teams with engineered fastening solutions tailored to critical applications. Contact the engineering team today to request a technical datasheet or quotation for your project requirements.
