Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 800H Washers
Incoloy 800H washers are bearing-surface and loose-prevention spacers machined from ASTM B409 plate (flat washers) or cold-formed from ASTM B408 bar stock (spring and locking washers) for high-temperature petrochemical and refinery flange-bolting service to 815 deg C (1500 deg F). TorqBolt manufactures three washer families on a single page: flat washers to DIN 125 / ISO 7089 for load distribution under nut bearing faces, spring washers to DIN 127 for elastic loose-prevention, and external-tooth locking washers to DIN 6798 for tooth-bite loose-prevention. Standard diameter range is M6 to M48 for all three variants, matched to the bolt or stud thread diameter. Every washer ships with EN 10204 type 3.1 mill test certificate documenting heat number, ASTM B408 (bar) or B409 (plate) chemistry, solution-anneal cycle and ASTM grain size verification. Note: for high-temperature sustained service, the all-metal DIN 980 lock nut is generally preferred over spring or locking washers for primary loose-prevention.
Washer Dimensions (DIN 125, DIN 127, DIN 6798)
| Size designation | Across flats / OD | Head / nut height | Thread pitch | Standard reference |
|---|---|---|---|---|
| M6 | Inner 6.4 mm | Outer 12.0 mm; Thickness 1.6 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M8 | Inner 8.4 mm | Outer 16.0 mm; Thickness 1.6 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M10 | Inner 10.5 mm | Outer 20.0 mm; Thickness 2.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M12 | Inner 13.0 mm | Outer 24.0 mm; Thickness 2.5 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M16 | Inner 17.0 mm | Outer 30.0 mm; Thickness 3.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M20 | Inner 21.0 mm | Outer 37.0 mm; Thickness 3.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M24 | Inner 25.0 mm | Outer 44.0 mm; Thickness 4.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M30 | Inner 31.0 mm | Outer 56.0 mm; Thickness 4.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M36 | Inner 37.0 mm | Outer 66.0 mm; Thickness 5.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
| M48 | Inner 50.0 mm | Outer 88.0 mm; Thickness 6.0 mm (flat) | n/a | DIN 125 / DIN 127 / DIN 6798 |
Manufacturing Route at TorqBolt
Flat washers are punched from plate stock; spring and locking washers are cold-formed from bar stock with post-form solution anneal where applicable:
- Flat washer route: receive Incoloy 800H plate to ASTM B409; PMI verification.
- Punch flat washers to DIN 125 ID + OD on hydraulic press; controlled punch-clearance to minimize burr.
- Deburr both sides; flatness verified.
- Solution anneal at 1149 deg C plateau followed by rapid quench; ASTM grain size 5 verified.
- Spring washer route: receive Incoloy 800H bar to ASTM B408; cold-form to DIN 127 split-ring profile.
- Locking washer route: cold-form external teeth to DIN 6798 profile from bar or plate stock.
- Spring and locking variants: post-form stress-relief at 870 deg C for 2 hours; ASTM grain size verified.
- Hardness check, dimensional verification, PMI on each batch.
- Pack matched with bolt or nut assemblies on PO call-out; CoC + EN 10204 cert.
Washer Sizes Stocked and Lead Times
| Diameter range | Length range | Stock status | Lead time |
|---|---|---|---|
| M6 - M16 flat | Per DIN 125 | Stock + ex-stock | 7 working days |
| M20 - M36 flat | Per DIN 125 | Made-to-order from stock plate | 10 to 14 working days |
| M6 - M24 spring | Per DIN 127 | Made-to-order from stock bar | 14 to 21 working days |
| M6 - M24 locking | Per DIN 6798 | Made-to-order from stock bar | 14 to 21 working days |
Inspection and Heat Marking
Washer specific inspections cover hole-diameter, OD, thickness, flatness (flat washers) and spring-tension (spring washers):
- Inner diameter verified to receive bolt shank with clearance.
- Outer diameter verified per DIN 125 / 127 / 6798 schedule.
- Thickness verified per DIN schedule with controlled tolerance.
- Flatness verified for flat washers (within 0.1 mm over 10 mm).
- Spring tension verified for DIN 127 split-ring washers (gap angle per schedule).
- Tooth profile verified for DIN 6798 external-tooth locking washers.
- Hardness band 120-184 HB; ASTM E112 grain-size etch verification.
- PMI by X-ray fluorescence on first piece and one per batch.
Typical Service Conditions
Washers are specified as load-distribution spacers under nut bearing faces and as loose-prevention elements on bolted assemblies:
- Flat washers under heavy hex nuts on pressure-vessel flange joints for load distribution.
- Flat washers under anchor bolt top-nuts on structural base plates.
- Spring washers under hex nuts on access-cover bolting subject to thermal cycling.
- Locking washers under hex bolts on heat exchanger baffle bolting.
- Spacer washers under eye bolts for height adjustment.
- U-bolt saddle-plate flat washers on pipe-support clamping.
Incoloy 800H Alloy Considerations on This Fastener Form
Companion Fasteners and Related Pages
- Hex Nuts: matched standard nuts for washer assemblies.
- Heavy Hex Nuts: matched heavy-pattern nuts for pressure-vessel bolting.
- Lock Nuts: all-metal prevailing-torque alternative for high-temperature loose-prevention.
- Hex Bolts: matched bolts for washer assemblies.
- Stud Bolts: matched studs for washer assemblies.
Frequently Asked Questions
Q. Are spring washers effective at high temperature?
DIN 127 spring washers lose their elastic preload above approximately 540 deg C as the spring temper relaxes. For high-temperature loose-prevention the all-metal DIN 980 lock nut is generally preferred. Spring washers remain useful for ambient and moderate-temperature service.
Q. What is the difference between DIN 6798A and DIN 6798V?
DIN 6798A is the external-tooth locking washer (teeth on the outer edge). DIN 6798V is the internal-tooth locking washer (teeth on the inner edge). Both use the tooth-bite principle for loose-prevention.
Q. Can flat washers be punched from B408 bar instead of B409 plate?
Flat washers from bar are not standard; bar stock is round and produces high scrap when punched into flat washers. Plate stock (B409) is the standard source for flat washers. Bar may be used for small-batch custom washers on PO call-out.
Q. Are washers available in inch sizes?
Yes. ANSI / ASME B18.21.1 flat washers, B18.21.1 spring washers and B18.21.2 locking washers in 1/4 inch through 2 inch are machined on PO call-out.
Q. Do you supply matched washer-bolt-nut sets?
Yes. Default supply is component-level (washers only). Matched sets are supplied when ordered with the bolt and nut line item from the same heat batch.
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