Description
Nickel-iron-chromium alloy industrial valve
Alloy 20 Floating Ball Valve
A chemical-process valve material associated with sulfuric-acid, pickling and fertilizer duties. The floating ball valve configuration is engineered for fast on-off isolation in process and utility piping.
What is a Alloy 20 Floating Ball Valve?
A Alloy 20 Floating Ball Valve combines a nickel-iron-chromium alloy containing copper and molybdenum, developed for resistance in sulfuric-acid and related chemical environments with a compact quarter-turn isolation design in which line pressure loads the floating ball against the downstream seat.
Alloy 20 selection must use concentration-temperature corrosion data and account for contaminants, aeration, velocity and crevices. Floating-ball suitability depends on size, differential pressure, seat load, operating torque and cavity-pressure behavior.
Alloy 20 Floating Ball Valve specifications
| Product | Alloy 20 Floating Ball Valve |
|---|---|
| Valve construction | One-, two- or three-piece floating-ball construction; full or reduced bore |
| 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 608, ISO 17292 and ASME B16.34; API 6D only when specifically designed and ordered |
| Pressure testing | API 598 or project-specified shell and closure testing |
| Pressure rating | ASME Class or PN rating verified against exact material, size, construction and design temperature |
| End connections | RF/RTJ flanged, threaded, socket-weld or butt-weld according to design |
| Operation | Lever, 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. |
Floating Ball Valve design and standards
API 608 / ISO 17292
Common design bases for industrial metal ball valves; exact scope and edition must be stated.
ASME B16.34
Pressure-temperature, material, design, examination, testing and marking requirements within scope.
API 598
Common shell and closure pressure-testing basis when specified.
API 607 / API 6FA
Fire-test qualification applies only to the exact offered seat, seal and valve configuration.
Seat polymer or metal, ball/stem alloy, packing, anti-static device, blowout-resistant stem, cavity relief and actuator torque must be selected together.
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 | Seat compatibility, differential pressure, cavity relief, torque and fire-safe/emissions requirements |
| Fertilizer | Acid and chemical handling systems after compatibility review | Seat compatibility, differential pressure, cavity relief, torque and fire-safe/emissions requirements |
| Pickling | Selected acid circulation and transfer duties | Seat compatibility, differential pressure, cavity relief, torque and fire-safe/emissions requirements |
| Pharmaceutical and fine chemical | Corrosive reagent and batch-process systems | Seat compatibility, differential pressure, cavity relief, torque and fire-safe/emissions requirements |
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 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
- Full or reduced bore, seat material, cavity relief, anti-static/fire-safe and actuator requirements
- 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.
How does a floating ball valve achieve shutoff?
Line pressure moves the ball slightly toward the downstream seat, producing pressure-assisted sealing. Seat material and geometry control leakage and operating torque.
When should a trunnion-mounted design be considered?
Trunnion mounting is commonly evaluated as size, pressure, torque, seat-load control or pipeline-service requirements increase.
Can Alloy 20 be used for every component in this floating ball 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 ball valves guide or browse all Ball Valves.
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