Description
Nickel-iron-chromium alloy industrial valve
Alloy 20 Globe Valve
A chemical-process valve material associated with sulfuric-acid, pickling and fertilizer duties. The globe valve configuration is engineered for frequent isolation and regulated process flow.
What is a Alloy 20 Globe Valve?
A Alloy 20 Globe Valve combines a nickel-iron-chromium alloy containing copper and molybdenum, developed for resistance in sulfuric-acid and related chemical environments with a linear-motion design in which a disc or plug moves perpendicular to the seat for isolation or controlled throttling.
Alloy 20 selection must use concentration-temperature corrosion data and account for contaminants, aeration, velocity and crevices. Pressure drop, cavitation, noise, velocity, plug contour, flow direction and actuator sizing must be checked for throttling service.
Alloy 20 Globe Valve specifications
| Product | Alloy 20 Globe Valve |
|---|---|
| Valve construction | Bolted-bonnet T-pattern globe valve; Y-pattern or angle pattern as separate engineered options |
| Nominal material | Alloy 20 |
| UNS / EN reference | UNS N08020; EN 2.4660 |
| Product forms | Wrought/forged ASTM B462 or ASTM A182 F20 as applicable; cast ASTM A351 CN7M; component specification controlled by design |
| Design standards | API 623 and ASME B16.34; API 602 for applicable compact forged designs |
| Pressure testing | API 598 or project-specified shell, backseat and closure testing |
| Pressure rating | ASME Class or PN rating verified against exact material, size, construction and design temperature |
| End connections | RF/RTJ flanged or butt-weld ends according to design |
| Operation | Handwheel, gearbox, pneumatic or electric actuator |
| Documentation | EN 10204 3.1 material records, pressure test report, GA drawing and project inspection records as ordered |
This is an engineered inquiry product, not a universal stock specification. Final availability depends on valve size, pressure class, material form, trim, seat system, operator, quantity and required code edition.
Alloy 20 material selection
| Selection point | Engineering guidance |
|---|---|
| Material profile | a nickel-iron-chromium alloy containing copper and molybdenum, developed for resistance in sulfuric-acid and related chemical environments |
| Why it is selected | Useful resistance to sulfuric acid and a range of chemical environments, with fabrication characteristics familiar to stainless-alloy shops. |
| Typical service | Sulfuric-acid processing, fertilizer, pickling, chemical transfer and pharmaceutical process systems. |
| Limitations to check | It is not a universal acid alloy. Hydrochloric acid, oxidizing contaminants and mixed acids can change performance significantly. |
| Specification route | Wrought/forged ASTM B462 or ASTM A182 F20 as applicable; cast ASTM A351 CN7M; component specification controlled by design |
| Verification | PMI for nickel, chromium, copper and molybdenum plus heat traceability and component-specific MTC review. |
Globe Valve design and standards
API 623
Common design basis for steel globe valves with flanged or butt-welding ends.
ASME B16.34
Pressure-temperature, material and general valve requirements within scope.
API 598
Shell, backseat and closure pressure testing when specified.
IEC 60534
Relevant when the product is engineered as a control valve with defined sizing and performance requirements.
Body pattern, plug contour, seat/hardfacing, flow direction, packing, pressure drop and actuator thrust must reflect the actual regulating or isolation duty.
Fire-safe, fugitive-emission, sour-service, oxygen, cryogenic, chlorine and PED requirements apply only when explicitly defined and supported for the exact offered configuration.
Typical applications
| Industry | Material service context | Valve selection focus |
|---|---|---|
| Sulfuric-acid processing | Transfer, dilution and process systems within verified concentration-temperature limits | Pressure drop, plug/seat trim, cavitation, flow direction, leakage and operating thrust |
| Fertilizer | Acid and chemical handling systems after compatibility review | Pressure drop, plug/seat trim, cavitation, flow direction, leakage and operating thrust |
| Pickling | Selected acid circulation and transfer duties | Pressure drop, plug/seat trim, cavitation, flow direction, leakage and operating thrust |
| Pharmaceutical and fine chemical | Corrosive reagent and batch-process systems | Pressure drop, plug/seat trim, cavitation, flow direction, leakage and operating thrust |
Application examples are not a corrosion or design approval. The end user must verify process chemistry, contaminants, pressure, temperature, velocity, cycling, emissions and regulatory requirements.
Quality, testing and traceability
Heat-number traceability and EN 10204 3.1 records matched to the ordered component specifications.
PMI for nickel, chromium, copper and molybdenum plus heat traceability and component-specific MTC review.
API 598 or project-specified shell, backseat and closure testing, with acceptance and leakage criteria stated on the order.
GA drawing, dimensions, marking, operation, pressure test and specified NDE/third-party records.
RFQ checklist
- Valve design standard and required edition
- Nominal size and ASME Class or PN rating
- Exact material specifications for pressure boundary, trim, seats, packing and bolting
- T/Y/angle pattern, isolation or throttling duty, flow coefficient/process data and trim contour
- End connection, facing and face-to-face requirement
- Fluid composition, concentration, contaminants and solids
- Design and operating pressure/temperature
- PMI, corrosion testing, NDE, witnessing and document requirements
Frequently asked questions
Why is Alloy 20 used in sulfuric-acid service?
Its nickel, chromium, molybdenum and copper balance can provide useful resistance across selected sulfuric-acid conditions. Exact concentration, temperature and contaminants remain decisive.
What cast grade is commonly associated with Alloy 20 valves?
ASTM A351 CN7M is a commonly specified cast grade associated with Alloy 20-type service. Forged components use their applicable wrought specification.
Can Alloy 20 replace Hastelloy C276?
Not as a blanket substitution. The alloys have different chemistry, strength and corrosion behavior. Selection must follow actual process corrosion data and the piping material specification.
Can a globe valve be used for throttling?
Yes, but the plug contour, pressure drop, cavitation, noise, velocity and actuator requirements must be engineered for the actual process.
How does a globe valve differ from a gate valve?
A globe valve provides better regulation but higher pressure drop. A gate valve offers a straighter flow path and is mainly used for full-open/full-closed isolation.
Can Alloy 20 be used for every component in this globe valve?
Not automatically. Pressure-boundary, trim, stem or shaft, seating, packing, gasket and bolting materials have different mechanical and corrosion duties. The complete bill of materials must be engineered for the service.
Related Alloy 20 valve products
Need a broader comparison? View the general stainless steel and alloy globe valves guide or browse all Globe Valves.
Request a Alloy 20 Globe Valve quotation
Send the valve specification, exact material grades, size, pressure class, operating conditions, quantity and inspection requirements for technical review.
