DIN 7603 C Sealing Ring Washers (Form C)
DIN 7603 form C sealing rings — the stepped bonded sealing washer for counterbored seats, sizes Φ4 ×8 to Φ64 ×70, with the collected bore/OD/sheet-thickness/lip ladder and per-material kg/1000 figures.
Last updated: 2026-11
Specifications
DIN 7603 form C is the stepped member of the bonded sealing-ring pair: where the seat for the washer is counterbored or recessed, the form C profile drops into the recess and its elastomer lip seals at the bottom while the metal ring spans the counterbore edge — the geometry form A cannot span. The collected ladder runs the source's Φd ×dc size naming from Φ4 ×8 to Φ64 ×70 (fasteners M4 to M64), and per size tabulates: bore d1 min/max (min = nominal size), outside diameter d2 min/max, the metal-sheet thickness e (0.12 – 0.2 mm across the range), the lip height h with material legend "AlFA,CuFA,StFA" (aluminium, copper and steel carriers with the FA elastomer), 1.5 mm nominal lip height throughout, and the ±25% kg/1000 mass per material. Note the collected form C ladder stops at Φ64 ×70 — larger counterbored seats are outside this source's tabulation (the form A ladder runs to Φ90 ×100). Sealing duty, not structure: size by the fastener and seat, and name the sealed medium when requesting the compound — the elastomer specification is not tabulated by the collected source and stays per RFQ.
| Standard | DIN 7603 form C — sealing rings, stepped form for counterbored seats |
|---|---|
| Size range | Φ4 ×8 – Φ64 ×70 in the source's "Φd ×dc" notation, fasteners M4 – M64 (form C ladder ends at Φ64 ×70 per the source) |
| Bore diameter | d1: min = nominal size, max per size (e.g. Φ12: 12.5) |
| Outside diameter | d2: max = nominal size per the size token, min/max rows per size |
| Sheet thickness | e: 0.12 – 0.2 mm, single value per size |
| Lip height | h per material legend AlFA,CuFA,StFA: 1.5 mm nominal (max 1.7 / min 1.3) |
| Weight | kg/1000 pcs ±25% per material (AlFA/StFA/CuFA) carried verbatim |
| Elastomer compound / finish | Not tabulated by the collected specification — per RFQ |
| Size | Φ4 ×8 | Φ5 ×7.5 | Φ5.5 ×8 |
|---|---|---|---|
| d1 — min=nominal size | 4.2 | 5.2 | 5.7 |
| max | 4.5 | 5.5 | 6 |
| d2 — max=nominal size | 7.9 | 7.4 | 7.9 |
| min | 7.7 | 7.2 | 7.7 |
| e | 0.2 | 0.12 | 0.12 |
| h — AlFA,CuFA,StFA — Nominal Size | 1.5 | 1.5 | 1.5 |
| max | 1.7 | 1.7 | 1.7 |
| min | 1.3 | 1.3 | 1.3 |
| per 1000 units≈kg — ±25% — AlFA | 0.085 | 0.066 | 0.071 |
| StFA | 0.2 | 0.16 | 0.173 |
| CuFA | 0.222 | 0.178 | 0.192 |
| Size | Φ6.5 ×9.5 | Φ8 ×11.5 | Φ10 ×13.5 |
|---|---|---|---|
| d1 — min=nominal size | 6.7 | 8.2 | 10.2 |
| max | 7 | 8.5 | 10.5 |
| d2 — max=nominal size | 9.4 | 11.4 | 13.4 |
| min | 9.2 | 11.2 | 13.2 |
| e | 0.15 | 0.17 | 0.17 |
| h — AlFA,CuFA,StFA — Nominal Size | 1.5 | 1.5 | 1.5 |
| max | 1.7 | 1.7 | 1.7 |
| min | 1.3 | 1.3 | 1.3 |
| per 1000 units≈kg — ±25% — AlFA | 0.09 | 0.125 | 0.155 |
| StFA | 0.218 | 0.328 | 0.368 |
| CuFA | 0.242 | 0.339 | 0.408 |
| Size | Φ12 ×15.5 | Φ12 ×16 | Φ14 ×18 |
|---|---|---|---|
| d1 — min=nominal size | 12.2 | 12.2 | 14.2 |
| max | 12.5 | 12.5 | 14.5 |
| d2 — max=nominal size | 15.4 | 15.9 | 17.9 |
| min | 15.2 | 15.7 | 17.7 |
| e | 0.17 | 0.2 | 0.2 |
| h — AlFA,CuFA,StFA — Nominal Size | 2 | 2 | 2 |
| max | 2.3 | 2.3 | 2.3 |
| min | 1.7 | 1.7 | 1.7 |
| per 1000 units≈kg — ±25% — AlFA | 0.218 | 0.234 | 0.268 |
| StFA | 0.515 | 0.554 | 0.635 |
| CuFA | 0.573 | 0.615 | 0.705 |
| Size | Φ14 ×20 | Φ15 ×19 | Φ16 ×20 |
|---|---|---|---|
| d1 — min=nominal size | 14.2 | 15.2 | 16.2 |
| max | 14.5 | 15.5 | 16.5 |
| d2 — max=nominal size | 19.9 | 18.9 | 19.9 |
| min | 19.7 | 18.7 | 19.7 |
| e | 0.3 | 0.2 | 0.2 |
| h — AlFA,CuFA,StFA — Nominal Size | 2 | 2 | 2 |
| max | 2.3 | 2.3 | 2.3 |
| min | 1.7 | 1.7 | 1.7 |
| per 1000 units≈kg — ±25% — AlFA | 0.428 | 0.284 | 0.3 |
| StFA | 0.965 | 0.675 | 0.712 |
| CuFA | 1.07 | 0.747 | 0.79 |
| Size | Φ17 ×21 | Φ18 ×22 | Φ20 ×24 |
|---|---|---|---|
| d1 — min=nominal size | 17.2 | 18.2 | 20.2 |
| max | 17.5 | 18.5 | 20.5 |
| d2 — max=nominal size | 20.9 | 21.9 | 23.9 |
| min | 20.7 | 21.7 | 23.7 |
| e | 0.2 | 0.2 | 2 |
| h — AlFA,CuFA,StFA — Nominal Size | 2 | 2 | 2 |
| max | 2.3 | 2.3 | 2.3 |
| min | 1.7 | 1.7 | 1.7 |
| per 1000 units≈kg — ±25% — AlFA | 0.342 | 0.335 | 0.368 |
| StFA | 0.755 | 0.793 | 0.871 |
| CuFA | 0.837 | 0.88 | 0.966 |
| Size | Φ21 ×26 | Φ22 ×27 | Φ23 ×28 |
|---|---|---|---|
| d1 — min=nominal size | 21.2 | 22.2 | 23.3 |
| max | 21.5 | 22.5 | 23.6 |
| d2 — max=nominal size | 25.9 | 26.9 | 27.9 |
| min | 25.7 | 26.7 | 27.7 |
| e | 0.25 | 0.25 | 0.25 |
| h — AlFA,CuFA,StFA — Nominal Size | 2 | 2 | 2.5 |
| max | 2.3 | 2.3 | 2.9 |
| min | 1.7 | 1.7 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 0.508 | 0.517 | 0.648 |
| StFA | 1.17 | 1.23 | 1.46 |
| CuFA | 1.3 | 1.35 | 1.62 |
| Size | Φ24 ×29 | Φ25 ×30 | Φ26 ×31 |
|---|---|---|---|
| d1 — min=nominal size | 24.3 | 25.3 | 26.3 |
| max | 24.6 | 25.6 | 26.6 |
| d2 — max=nominal size | 28.9 | 29.9 | 30.9 |
| min | 28.7 | 29.7 | 30.7 |
| e | 0.25 | 0.25 | 0.25 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 0.665 | 0.693 | 0.716 |
| StFA | 1.49 | 1.56 | 1.63 |
| CuFA | 1.66 | 1.73 | 1.79 |
| Size | Φ27 ×32 | Φ28 ×33 | Φ30 ×36 |
|---|---|---|---|
| d1 — min=nominal size | 27.3 | 28.3 | 30.3 |
| max | 27.6 | 28.6 | 30.6 |
| d2 — max=nominal size | 31.9 | 32.9 | 35.9 |
| min | 31.7 | 32.7 | 35.7 |
| e | 0.25 | 0.25 | 0.3 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 0.74 | 0.765 | 0.955 |
| StFA | 1.67 | 1.72 | 2.14 |
| CuFA | 1.85 | 1.91 | 2.38 |
| Size | Φ32 ×38 | Φ33 ×39 | Φ35 ×41 |
|---|---|---|---|
| d1 — min=nominal size | 32.3 | 33.3 | 35.3 |
| max | 32.6 | 33.6 | 35.6 |
| d2 — max=nominal size | 37.9 | 38.9 | 40.9 |
| min | 37.7 | 38.7 | 40.7 |
| e | 0.3 | 0.3 | 0.3 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 1.015 | 1.04 | 1.1 |
| StFA | 2.28 | 2.44 | 2.48 |
| CuFA | 2.53 | 2.6 | 2.75 |
| Size | Φ36 ×42 | Φ38 ×44 | Φ39 ×46 |
|---|---|---|---|
| d1 — min=nominal size | 36.3 | 38.3 | 39.3 |
| max | 36.6 | 38.6 | 39.6 |
| d2 — max=nominal size | 41.9 | 43.9 | 45.9 |
| min | 41.7 | 43.7 | 45.7 |
| e | 0.2 | 0.3 | 0.35 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 1.66 | 1.18 | 1.43 |
| StFA | 2.54 | 2.66 | 3.4 |
| CuFA | 2.82 | 2.95 | 3.42 |
| Size | Φ40 ×47 | Φ42 ×49 | Φ44 ×51 |
|---|---|---|---|
| d1 — min=nominal size | 40.3 | 42.3 | 44.3 |
| max | 40.6 | 42.6 | 44.6 |
| d2 — max=nominal size | 46.9 | 48.9 | 50.9 |
| min | 46.7 | 48.7 | 50.7 |
| e | 0.35 | 0.35 | 0.35 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 1.47 | 1.57 | 1.6 |
| StFA | 3.16 | 3.3 | 3.44 |
| CuFA | 3.5 | 3.66 | 3.82 |
| Size | Φ45 ×52 | Φ48 ×55 | Φ50 ×57 |
|---|---|---|---|
| d1 — min=nominal size | 45.3 | 48.3 | 50.2 |
| max | 45.6 | 48.6 | 50.5 |
| d2 — max=nominal size | 51.9 | 54.9 | 56.9 |
| min | 51.7 | 54.7 | 56.7 |
| e | 0.35 | 0.35 | 0.35 |
| h — AlFA,CuFA,StFA — Nominal Size | 2.5 | 2.5 | 2.5 |
| max | 2.9 | 2.9 | 2.9 |
| min | 2.1 | 2.1 | 2.1 |
| per 1000 units≈kg — ±25% — AlFA | 1.64 | 1.74 | 1.81 |
| StFA | 3.51 | 3.74 | 3.83 |
| CuFA | 3.9 | 4.15 | 4.3 |
| Size | Φ52 ×60 | Φ54 ×62 | Φ55 ×63 |
|---|---|---|---|
| d1 — min=nominal size | 52.5 | 54.5 | 55.5 |
| max | 53 | 55 | 56 |
| d2 — max=nominal size | 59.8 | 61.8 | 62.8 |
| min | 59.5 | 61.5 | 62.5 |
| e | 0.4 | 0.4 | 0.4 |
| h — AlFA,CuFA,StFA — Nominal Size | 3 | 3 | 3 |
| max | 3.5 | 3.5 | 3.5 |
| min | 2.5 | 2.5 | 2.5 |
| per 1000 units≈kg — ±25% — AlFA | 2.3 | 2.38 | 2.42 |
| StFA | 4.77 | 4.92 | 5 |
| CuFA | 5.3 | 5.46 | 5.56 |
| Size | Φ56 ×64 | Φ58 ×66 | Φ60 ×68 |
|---|---|---|---|
| d1 — min=nominal size | 56.5 | 58.5 | 60.5 |
| max | 57 | 59 | 61 |
| d2 — max=nominal size | 63.8 | 65.8 | 67.8 |
| min | 63.5 | 65.5 | 67.5 |
| e | 0.4 | 0.4 | 0.4 |
| h — AlFA,CuFA,StFA — Nominal Size | 3 | 3 | 3 |
| max | 3.5 | 3.5 | 3.5 |
| min | 2.5 | 2.5 | 2.5 |
| per 1000 units≈kg — ±25% — AlFA | 2.46 | 2.55 | 2.63 |
| StFA | 5.1 | 5.27 | 5.41 |
| CuFA | 5.65 | 5.85 | 6 |
| Size | Φ64 ×72 | Φ65 ×74 | Φ70 ×79 |
|---|---|---|---|
| d1 — min=nominal size | 64.5 | 65.5 | 70.5 |
| max | 65 | 66 | 71 |
| d2 — max=nominal size | 71.8 | 73.8 | 78.8 |
| min | 71.5 | 73.5 | 78.5 |
| e | 0.4 | 0.45 | 0.45 |
| h — AlFA,CuFA,StFA — Nominal Size | 3 | 3 | 3 |
| max | 3.5 | 3.5 | 3.5 |
| min | 2.5 | 2.5 | 2.5 |
| per 1000 units≈kg — ±25% — AlFA | 2.85 | 3.44 | 3.68 |
| StFA | 5.75 | 6.9 | 7.39 |
| CuFA | 6.35 | 7.65 | 8.2 |
| Size | Φ75 ×84 | Φ78 ×88 | Φ80 ×90 |
|---|---|---|---|
| d1 — min=nominal size | 75.5 | 78.5 | 80.7 |
| max | 76 | 79 | 81.2 |
| d2 — max=nominal size | 83.8 | 87.8 | 89.8 |
| min | 83.5 | 87.5 | 89.5 |
| e | 0.45 | 0.5 | 0.5 |
| h — AlFA,CuFA,StFA — Nominal Size | 3 | 3 | 3 |
| max | 3.5 | 3.5 | 3.5 |
| min | 2.5 | 2.5 | 2.5 |
| per 1000 units≈kg — ±25% — AlFA | 3.93 | 4.6 | 4.73 |
| StFA | 7.87 | 8.95 | 9.28 |
| CuFA | 8.75 | 9.95 | 10 |
| Size | Φ85 ×95 | Φ90 ×100 |
|---|---|---|
| d1 — min=nominal size | 85.7 | 90.7 |
| max | 86.2 | 91.2 |
| d2 — max=nominal size | 94.8 | 99.8 |
| min | 94.5 | 99.5 |
| e | 0.5 | 0.5 |
| h — AlFA,CuFA,StFA — Nominal Size | 3 | 3 |
| max | 3.5 | 3.5 |
| min | 2.5 | 2.5 |
| per 1000 units≈kg — ±25% — AlFA | 4.95 | 5.23 |
| StFA | 9.7 | 10.2 |
| CuFA | 10.7 | 11.3 |
Materials
- Carrier material per the source legend: AlFA (aluminium), CuFA (copper), StFA (steel), each with the FA elastomer lip; compound and hardness per RFQ — state the sealed medium and temperature at quotation
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 7603 C Sealing Ring Washers (Form C)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Why does the form C ladder stop at Φ64 ×70 while form A runs to Φ90 ×100?
That is the extent of the collected source's tabulation, and it mirrors where the two forms are actually used: very large bonded sealing rings see duty on flat-faced housings — drain plugs, level sights, large cover bolts — where form A's simple flat profile is all the seat needs, so the form A table keeps going. Stepped seats (counterbored recesses) concentrate in the medium-size machine range, and the form C table ends at Φ64 ×70 there. If your drawing calls a larger form C, quote the size and seat detail per RFQ rather than substituting form A — the step height that clears the counterbore edge is a drawn dimension the flat form does not have. Both forms' elastomer compounds are outside the collected tables and are confirmed at quotation from the medium and temperature you name.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support