Washers are optional in PCC-1, but when used they should be through-hardened. They give the nut a smooth, hard bearing face, which keeps the nut factor steady and protects the flange. A printable PDF (PB-TD-215) is below. Values are for reference; confirm against the current edition of the governing standard. Send us your bolting list for a quote or call (281) 581-0176.
Related: ASTM F436 Washers · Belleville Washers and Live Loading · All technical docs
Washer types (App M-1.5, M-2)
| Type | Material | Use with | Hardness |
|---|---|---|---|
| 1 | Carbon steel | Steel nuts (2H, 4, 7) | 38–45 HRC |
| 4 | Low-alloy steel (4130/4140) | Steel nuts (2H, 4, 7) | 38–45 HRC |
| 5 | Martensitic stainless (S41000) | Grade 8 austenitic nuts | 38–45 HRC |
| 6 | Precipitation-hardened stainless (S17400) | Grade 8 austenitic nuts | 33–42 HRC |
| 7 | Austenitic (S21800) | Low temperature, about −50 to −300°F | 20–23 HRC |
Temperature limits (App M-1.3)
| Type | Single use | Reuse |
|---|---|---|
| 1 | 800°F | 400°F (galling risk above 600°F) |
| 4 | 1,000°F | 750°F |
| 5 | 1,200°F | 800°F |
| 6 | 1,500°F | 1,025°F |
| 7 | Low temperature service | – |
Key points
- Through-hardened washers are recommended. Surface-hardened washers are not.
- Type 1 matches an ASTM F436 Type 1 washer. Some F436 sizes interfere with flange spot faces or back faces, and F436 does not cover every size (M-1.4).
- Install with the marked face toward the flange (M-1.6).
- Washers are marked with the type number, depressed, on one face.
- Sizes covered: 1/2 to 4 in. bolts. Use the dimensions in PCC-1 App M or your purchase specification.
Ordering
Patriot Bolt supplies through-hardened flange washers to your specification with stud bolts and nuts. Allow for washer thickness in stud length using the Stud Bolt Length Calculator.
References: ASME PCC-1-2026, Guidelines for Pressure Boundary Bolted Flange Joint Assembly · ASTM F436, Hardened Steel Washers. Summaries are paraphrased; clause numbers refer to ASME PCC-1-2026 unless noted. Patriot Bolt manufactures bolting and does not perform bolting, training or joint assembly services.