Quick answer: Hastelloy and titanium are not universal corrosion rankings. Screen the exact chemical, concentration, temperature, contaminants, chlorides/fluorides, oxidizing or reducing condition, velocity, solids, pressure, and seal system. Then specify the correct casting or wrought form and require MTR, heat-number traceability, PMI, and any agreed NDE or hydrostatic evidence.
Why Material Selection Cannot Start With the Fluid Name Alone
“Acid,” “chloride,” or a trade chemical can describe a wide range of operating conditions. Water content, impurities, temperature, flow velocity, aeration, solids, pressure, and shutdown chemistry can change corrosion mechanisms. The pump also exposes more than one material: casing, impeller, shaft, wear surfaces, fasteners, gaskets, elastomers, and mechanical-seal components may each have different compatibility requirements.
Define the service envelope before asking whether Hastelloy or titanium is “better.” A material recommendation without the chemistry range and temperature basis is only a candidate for review.
Hastelloy C-Family: Where It Is Considered
Hastelloy is a trade family name rather than one universal alloy. A buyer may be considering a specific C-family wrought designation, a cast grade, or another nickel-based alloy. Verify the exact specification, product form, heat treatment, mechanical requirements, and chemical limits for the component. Do not treat Hastelloy C-276 wrought designation and a pump casting grade as identical simply because the names look similar.
For an ANSI pump wet end, ask which components are actually supplied in the selected alloy and how the supplier controls melt, heat treatment, repair welding, machining, and traceability. A material certificate should identify the ordered specification and heat number, not only a marketing family name.
Titanium: Where It Is Considered
Titanium can be considered in some aggressive, chloride-bearing, or oxidizing services, but the exact grade and chemistry still matter. Fluoride, reducing acids, temperature, velocity, crevices, galvanic couples, and contamination can change the selection. The pump design must also account for strength, erosion, fasteners, gaskets, seal parts, and fabrication or casting requirements.
Do not specify titanium because a liquid is simply called “corrosive.” Put the chemistry, temperature, concentration, contaminants, and project-specific acceptance criteria in the RFQ.
Hastelloy vs Titanium: Screening Matrix
| Screening factor | Hastelloy family | Titanium family | Buyer action |
|---|---|---|---|
| Chemistry | Review exact alloy and oxidizing/reducing environment | Review exact grade and chemical mechanisms | Provide composition and contaminants |
| Concentration | Limits can change with concentration and water content | Limits can change with concentration and temperature | Give normal and upset range |
| Chlorides/fluorides | May affect localized attack and alloy choice | May materially change suitability in some acids | List halides explicitly |
| Temperature | Changes corrosion, strength, seal and casting behavior | Changes corrosion, strength and seal requirements | State continuous and excursion temperatures |
| Product form | Wrought designation and pump casting grade may differ | Grade, casting/wrought form and fabrication route matter | Write the material specification, not only family name |
| Velocity/solids | Can increase erosion-corrosion or wear | Can increase erosion and affect clearances | Provide flow, solids and particle data |
| Verification | MTR, heat traceability, PMI and NDE as specified | MTR, heat traceability, PMI and NDE as specified | Define acceptance records before order |
Casting Grade vs Wrought Alloy Name
“Hastelloy C-276” and “titanium” are not complete pump material specifications. Wrought products and cast pump components can use different designations, chemistry limits, mechanical requirements, heat treatments, and inspection methods. The supplier should state the exact casting or wrought specification for each pressure-containing and wetted component, along with any approved equivalency or deviation.
| Document field | What it should identify |
|---|---|
| Component | Casing, impeller, shaft, wear part, fastener, gasket or seal part |
| Specification | Exact material standard, grade, product form and heat treatment |
| Traceability | Heat number linked to the casting or finished component |
| Chemistry | Actual analysis or certificate basis required by the purchase specification |
| Inspection | PMI, OES, PT, RT/UT, mechanical tests or hydrostatic test as agreed |
| Deviation | Any substitution, repair, weld, machining limit or documentation exception |
PMI is valuable for screening and identity confirmation, but it does not replace the full MTR, heat-treatment record, casting quality evidence, dimensions, or a chemistry-specific engineering assessment. Use the Alloy 20 versus Hastelloy selection guide when that comparison is the actual project question.
Wet-End and Seal Compatibility
Review the seal faces, elastomers, springs, metal parts, gaskets, flush or quench fluid, and secondary containment with the same care as the casing and impeller. A corrosion-resistant wet end cannot compensate for an incompatible elastomer or seal face. Confirm dry-running risk, crystallization, solids, pressure direction, temperature, and the consequence of leakage.
For a chemical transfer application, combine this materials review with the chemical transfer pump selection guide. Candidate material does not equal a universal service guarantee.
Material Verification: MTR, PMI and Heat Traceability
- Freeze the specification: list exact component, grade, product form, heat treatment and applicable standard.
- Trace the heat: link the heat number from melt record/MTR to the casting, part, and final pump serial or manufacturing traveler.
- Verify identity: use PMI or OES when specified and retain the actual report, calibration details, location, and acceptance criteria.
- Inspect quality: apply PT, RT/UT, mechanical testing, hydrostatic testing, or other NDE only within the agreed inspection plan and service risk.
- Review deviations: record repairs, substitutions, welds, machining changes, and missing documents before shipment.
- Preserve the dossier: keep drawings, MTRs, heat treatment, inspection, test, seal, and packing records together.
Lifecycle and Lead-Time Considerations
A higher-alloy material may be justified by chemistry and consequence of failure, but the decision should include casting availability, machining, repair controls, spare strategy, inspection scope, and lead time. A lower-cost candidate that lacks traceability or cannot be inspected reliably may create more lifecycle risk than its purchase price suggests. Conversely, an exotic alloy should not be specified without a documented chemistry reason and a qualified supply route.
Chemical Pump RFQ Checklist
- Exact chemical composition, concentration range, temperature range, pH where relevant, contaminants, chloride/fluoride, oxidizing/reducing condition, gas, solids and velocity.
- Flow, TDH or pressure, suction conditions, vapor pressure, SG, viscosity, operating hours, starts, upset conditions and area classification.
- Wetted and pressure-containing component list with exact material specification and casting/wrought form.
- Seal faces, elastomers, gaskets, flush/quench, secondary containment, leak detection and isolation requirements.
- MTR, heat number, heat treatment, PMI/OES, NDE, hydrostatic, dimensional, performance, balance and documentation requirements.
- Approved drawings, change control, deviation process, sample records, packing requirements and spare-parts scope.
For a material and duty review, send the chemistry and component list through ANSI Pumps Pro contact. The OEM cross-reference process can be used when an exotic-alloy part must replace an installed component.
Frequently Asked Questions
Is Hastelloy more corrosion-resistant than titanium in every service?
No. The result depends on exact alloy or grade, chemistry, concentration, temperature, contaminants, velocity, solids, and component design.
Is PMI enough to verify a Hastelloy pump part?
No. PMI can support identity screening, but the order may also require MTRs, heat traceability, heat treatment, casting quality, dimensions, NDE, and hydrostatic or other tests.
Can titanium be specified for every corrosive chemical?
No. Review the exact chemistry, grade, temperature, halides, reducing conditions, velocity, galvanic interfaces, seals, and fabrication route.
What should a material quotation state?
It should identify each wetted and pressure-containing component, exact specification and product form, traceability, inspection scope, seal materials, deviations, and documents supplied.
