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Certifications: EN 10204 3.1 / 3.2 material test certificates and complete export documentation packages.
Hastelloy
A world-class technical reference for chemical process engineers navigating the complete Hastelloy nickel-alloy family beyond C-22 and C-276 — covering the B-series’ distinctive chromium- free chemistry for hydrochloric acid service, the counter- intuitive reason chromium is actually detrimental in strongly reducing acids, the G-series for phosphoric/sulfuric acid with chlorides, C-2000’s broadened single-alloy versatility, and the isocorrosion diagram methodology used to select among the family, plus the QC and documentation discipline required for critical Hastelloy component supply.
Nickel-Molybdenum Chemistry
& Why Chromium Is Detrimental in HCl
RR Hydraulic’s dedicated Hastelloy C-22 and C-276 references cover the nickel-chromium-molybdenum C-series in detail — the B-series represents a fundamentally different alloy family within the Hastelloy name, deliberately omitting chromium for a genuinely counter-intuitive but important metallurgical reason.
1.1 — Hastelloy B-3 (and Legacy B-2): Nickel-Molybdenum Chemistry
Hastelloy B-3 (and its predecessor B-2) is a nickel-molybdenum alloy (approximately 28–30% Mo, with essentially no significant chromium content) — a fundamentally different composition family from the nickel-chromium-molybdenum C-series discussed in detail throughout RR Hydraulic’s dedicated C-22 and C-276 references. B-3 is specifically engineered and widely specified for hydrochloric acid (HCl) service across a broad range of concentrations and temperatures, including boiling concentrated HCl conditions where even the C-series’ excellent broad-spectrum acid resistance is not the optimal, most cost-effective choice.
1.2 — The Counter-Intuitive Reason: Why Chromium Can Be Detrimental in Strongly Reducing HCl
1.3 — When to Specify B-Series Over C-Series
Specify Hastelloy B-3 specifically for hydrochloric acid process equipment — HCl production, HCl-based pickling and chemical processing, and any process stream where HCl is the dominant or sole aggressive chemistry — where its chromium-free composition provides genuinely superior resistance to the C-series alternatives. Where the process stream involves HCl alongside oxidizing species (dissolved oxygen, oxidizing contaminants, or mixed acid chemistry including oxidizing acids), the C-series’ chromium content becomes beneficial again for the oxidizing component of the environment — always evaluate the complete, actual process chemistry (not simply “HCl is present”) before defaulting to B-series, since a mixed or oxidizing-contaminated HCl stream may in fact favour a C-series alloy or, in some cases, the newer C-2000 grade discussed in Part 2.
& C-2000 —
Phosphoric Acid and Combined Oxidizing/Reducing Resistance
Two further Hastelloy families address specific gaps in the B-series/C-series coverage — G-series for phosphoric and sulfuric acid environments containing chlorides, and C-2000 as a newer-generation alloy specifically engineered to combine strengths that traditionally required choosing between different alloy families.
Submit series/grade, application, and quantity to sales@rrhydraulics.com for a certified offer.
2.1 — Hastelloy G-30: Phosphoric and Sulfuric Acid with Chlorides
Hastelloy G-30 is a nickel-chromium-molybdenum-copper-columbium (niobium) alloy specifically engineered for phosphoric acid production and processing environments, particularly where chloride contamination and other aggressive impurities common in industrial-grade (rather than laboratory-pure) phosphoric acid make standard austenitic stainless or even 904L (discussed in RR Hydraulic’s dedicated reference) inadequate. G-30’s specific combination of chromium (oxidizing acid resistance), molybdenum (general corrosion and pitting resistance), and copper (further enhancing resistance to sulfuric and phosphoric acid specifically, following the same copper-addition principle discussed for 904L and Incoloy 825 in RR Hydraulic’s dedicated references) makes it a standard specification for demanding phosphoric acid fertiliser production equipment.
2.2 — Hastelloy C-2000: Combining Oxidizing and Reducing Acid Resistance
2.3 — The Complete Hastelloy Family Reference
| Series / Grade | Base Chemistry | Primary Environment | RR Hydraulic Reference |
|---|---|---|---|
| B-3 (B-Series) | Ni-Mo (no significant Cr) | Hydrochloric acid — reducing conditions | This reference, Part 1 |
| C-276 | Ni-Cr-Mo (low C/Si) | Broad range, reducing-favoured, weldable without PWHT | Hastelloy C-276 reference |
| C-22 | Ni-Cr-Mo (higher Cr, lower Mo) | Oxidizing environments favoured over C-276 | Hastelloy C-22 reference |
| C-2000 | Ni-Cr-Mo-Cu | Combined oxidizing/reducing versatility | This reference, Section 2.2 |
| G-30 (G-Series) | Ni-Cr-Mo-Cu-Cb | Phosphoric/sulfuric acid with chlorides | This reference, Section 2.1 |
How the Chemical Process
Industry Actually Selects Among the Family
Selecting the correct Hastelloy grade for a specific process stream relies on a specific, standard engineering tool — isocorrosion diagrams — similar in principle to the Nelson and McConomy curves discussed for petrochemical service in RR Hydraulic’s dedicated Petrochemical reference, but organised around acid concentration and temperature for the specific acid chemistry.
3.1 — What Isocorrosion Diagrams Show and How They’re Used
Isocorrosion diagrams — published by Hastelloy’s manufacturer and widely referenced throughout the chemical process industry — plot lines of constant corrosion rate (commonly the boundary between acceptable, typically below 0.1 mm/year, and unacceptable corrosion rate) as a function of acid concentration (horizontal axis) and temperature (vertical axis), for a specific acid chemistry (sulfuric acid, hydrochloric acid, phosphoric acid, and others) and a specific alloy grade. By overlaying isocorrosion diagrams for different candidate alloys (B-3, C-276, C-22, C-2000, or G-30) for the same acid chemistry, a process engineer can directly compare which alloy provides acceptable corrosion resistance at the specific process stream’s actual concentration and temperature — the same fundamental engineering logic as the Nelson curve (hydrogen partial pressure vs. temperature) and McConomy curve (sulfur content vs. temperature) tools discussed in RR Hydraulic’s Petrochemical reference, applied here to acid concentration and temperature for corrosion-resistant alloy selection.
3.2 — Practical Application: Selecting Among the Family for a Specific Process Stream
Confirm the Complete Actual Process Chemistry
Isocorrosion diagram selection requires knowing the specific acid, its actual concentration and temperature range across normal and upset operating conditions, and any secondary contaminants (chlorides, oxidizing species, other acids) that may shift the effective corrosion environment away from the idealised single-acid diagram — always verify the complete process stream chemistry rather than selecting based on the primary acid alone.
Design for Upset and Off-Design Conditions, Not Just Normal Operation
Process upset conditions (higher-than-normal concentration or temperature excursions, contamination events) can push the effective corrosion environment into a more severe region of the isocorrosion diagram than normal operation — material selection should account for a reasonable range of off-design conditions the equipment may realistically experience, not solely the nominal steady-state design point.
Cross-Reference Against Actual Plant Experience Where Available
Published isocorrosion diagrams represent controlled laboratory testing conditions — actual plant experience with the specific alloy in a genuinely comparable process stream (where available) provides valuable additional confirmation or refinement of the diagram-based selection, particularly for complex, multi-component process streams that do not map cleanly to a single-acid laboratory test condition.
Industry Applications
& Documentation
RR Hydraulic maintains full traceability across the complete Hastelloy family, from certified heat/lot through finished, tested, and packed component shipment.
4.1 — Inspection & QC Protocol
4.2 — EN 10204 / Documentation Requirements
| Certificate | Content | EPC Requirement | When Mandatory |
|---|---|---|---|
| 2.1 / 2.2 | Declaration / non-specific | Not acceptable for critical acid process supply | Never for critical chemical process equipment supply |
| 3.1 (EN 10204) | Heat-traceable chemical + mechanical test report | Mandatory — all EPC supply | All chemical process and general project supply |
| 3.2 (EN 10204) | 3.1 + TPI countersign | Critical / owner-specified critical items | High-consequence acid process pressure equipment |
4.3 — Applications by Industry
Hydrochloric Acid Service
Hastelloy B-3 for HCl production, pickling, and general HCl process equipment, leveraging the chromium-free chemistry advantage discussed in detail in Part 1 — the standard, most corrosion-resistant material for this specific, demanding acid environment.
Phosphoric Acid and Mixed Process Chemistry
Hastelloy G-30 for phosphoric acid fertiliser production and other applications involving chloride-contaminated phosphoric/sulfuric acid, and C-2000 for process streams with variable or combined oxidizing/reducing character, per Part 2.
General Chemical Process Equipment
C-276/C-22 for the broad range of general chemical process applications discussed in detail throughout RR Hydraulic’s dedicated references, with isocorrosion diagram verification (Part 3) confirming correct grade selection against the specific process stream’s actual chemistry.
4.4 — Export Packaging Specification
- Hastelloy components packed by series and grade with clear labelling, given the significant corrosion performance differences across the B/C/G-series family discussed throughout this reference
- Heat/lot number marked or tagged on each item, cross-referenced to the accompanying material test certificate
- Components segregated from carbon steel and other dissimilar materials during packing per standard practice discussed throughout RR Hydraulic’s materials references
- Documentation in a waterproof pocket: EN 10204 3.1/3.2 MTC, chemical composition report, mechanical properties report, PMI report, corrosion test report (where specified), and packing list with series/grade/form/size breakdown per item
- ISPM-15 timber or export cartons for international shipment, with country of origin and HS tariff code documentation matched to the Hastelloy product category
Submit your series/grade, application, and quantity to RR Hydraulic for a complete, certified commercial offer.