Custom-machined large-bore ring-type joint gaskets in Hastelloy C-276 (UNS N10276) — the material of choice for hydrochloric acid, chlorine, and highly corrosive mixed acid service — in sizes from 10" to 52" bore to API 6A, ASME B16.20 and customer specification. All profiles: R oval, R octagonal, RX, kammprofile. Full EN 10204 3.1 mill test certificates with hardness certification. Kriloha supplies from UK, CFR Mumbai.
Three independent challenges — material availability, machining capability, and documentation — combine to make large-bore exotic alloy RTJ rings effectively unavailable from Indian suppliers.
Not stocked in large-diameter form by Indian material distributors. To machine a 16" RTJ ring, you need a forged ring or thick disc cut from 450–500mm diameter bar, which must be imported, adding 8–12 weeks before machining begins.
Kriloha maintains relationships with certified Hastelloy C-276 forging suppliers. We hold approved supplier status with EN 10204 3.1 material certification. For large-bore RTJ rings, we procure forged ring blanks to minimise machining allowance and lead time.
Hastelloy C-276 work-hardens rapidly, generates high cutting temperatures, and requires specialist tooling, low feed rates and constant coolant flow. Machining a 16" RTJ ring groove to API tolerances in C-276 requires CNC turning capability with appropriate tooling.
Ring face finish is inspected to 63 Ra (3.2 µm) for standard RTJ and 32 Ra (1.6 µm) for high-pressure API service. Dimensional inspection performed to ASME B16.20 Table 11 tolerances.
Requires EN 10204 3.1 MTC (not 3.2), chemical analysis, mechanical properties, hardness at multiple locations, dimensional inspection report, and full traceability from raw material heat number to finished ring serial number.
Full API 6A documentation package supplied as standard:
| UNS designation | N10276 |
| Ni content | 57% min |
| Mo content | 15–17% |
| Cr content | 14.5–16.5% |
| Max hardness (RTJ) | 200 BHN max |
| Tensile strength (min) | 690 MPa |
| NACE MR0175 | Compliant for sour gas H₂S service |
| Pitting resistance (PREN) | 44 — excellent chloride resistance |
| Delivery terms | CFR Mumbai; lead time 4–6 weeks |
| Available profiles | R oval, R octagonal, RX, kammprofile |
| Bore sizes | 2" to 52" nominal bore |
| Pressure class | ASME 600–2500 LBS · API 2,000–20,000 psi |
| Applicable standards | ASME B16.20 · API 6A · API 6BX |
| Dimensional tolerance | ASME B16.20 Table 11 · API 6A App. F (BX) |
| Ring face finish | 63 Ra (3.2 µm) standard; 32 Ra (1.6 µm) high-P |
| Documentation | EN 10204 3.1 MTC + hardness + dimensional + traceability |
| Optional extras | PMI, helium leak test, TPI (BV/TÜV) |
| Specialist bore range | 10" to 52" — not available from Indian suppliers |
Chlorine gas, HCl and sodium hypochlorite reactor nozzles require RTJ rings in Hastelloy C-276 — the only alloy with documented resistance to wet chlorine at operating temperatures.
Indian coal power plants retrofitting FGD systems see dilute sulphuric acid, chlorides and particulate slurry — conditions that corrode 316 SS rapidly. Hastelloy C-276 RTJ rings are specified for all high-pressure FGD connections.
Multi-purpose API pharmaceutical reactors handling mixed acid, HBr and chlorinated solvents specify Hastelloy C-276 for all high-pressure nozzle connections.
High H₂S partial pressure wells in the Bombay High and KG basin require NACE MR0175-compliant materials for all wellhead and flow line connections. Hastelloy C-276 is specified where both sour service and high chloride are present.
The more detail you provide, the faster we can respond. If you have a drawing, email it directly — we will review and respond within 24 hours.