Supreme Valves' Alloy 20 Product Configurations
Alloy 20 (CN7M) valves are the gold standard for process safety when standard austenitic SS316 CF8M fails due to localized chloride cracking or sulfuric acid attack. We manufacture and supply the following configurations:
Alloy 20 Gate Valves
Standards: API 603, API 600, ASME B16.34
Sizing: NPS 1/2" to 24" | Class 150/300/600
Designed for full-bore isolation, featuring a solid wedge gate, outside screw & yoke (OS&Y), bolted bonnet, and integral seat rings to eliminate boundary-leak points under hot acid flow.
Alloy 20 Wafer Check Valves
Standards: API 594, API 598, ASME B16.5
Sizing: NPS 2" to 12" | Class 150/300
Dual-plate or single-plate wafer non-return designs. Compact, light, featuring spring-assisted shut-off in Alloy 20 to prevent reverse flow in aggressive leaching lines.
Alloy 20 Ball Valves
Standards: API 608, API 607 (Fire-Safe), BS 5351
Sizing: NPS 1/2" to 8" | Class 150/300
Available in 2-piece and 3-piece full bore designs, lever or actuator-ready (ISO 5211). Features reinforced PTFE or PEEK soft seats for bubble-tight organic acid shut-off.
Alloy 20 Globe & Control Valves
Standards: BS 1873, ISA S75, ASME B16.34
Sizing: NPS 1/2" to 12" | Class 150/300/600
Bolted bonnet, plug disc throttling profile. Excellent for sulfuric acid dilution flow control, equipped with contoured seats for precise modulating parameters.
Sulfuric Acid Chemical Compatibility Matrix
Standard Stainless Steel 316 CF8M fails rapidly in sulfuric acid dilution processes due to high chemical dissolution rates. The chart below displays why **Alloy 20 (CN7M)** is mandatory for long-term valve life:
| Sulfuric Acid Concentration | Temperature Limit | Cast Iron / WCB | SS304 (CF8) | SS316 (CF8M) | Alloy 20 (CN7M) | Hastelloy C276 |
|---|---|---|---|---|---|---|
| Dilute Sulfuric Acid (5% - 20%) | Ambient to 60°C (140°F) | C - Poor | B - Moderate | B - Moderate | A - Excellent | A - Excellent |
| Medium Concentration (20% - 70%) | Ambient to 80°C (176°F) | C - Poor | C - Poor | C - Poor | A - Excellent | A - Excellent |
| Concentrated Acid (70% - 95%) | Ambient to 50°C (122°F) | B - Moderate | B - Moderate | B - Moderate | A - Excellent | A - Excellent |
| Highly Concentrated (96% - 98%) | Up to 80°C (176°F) | A - Passivates | B - Moderate | B - Moderate | A - Excellent | A - Excellent |
| Acid Dilution Lines (Process Mix) | Elevated up to 100°C (212°F) | C - Rapid Failure | C - Poor | C - Poor | A - Excellent | A - Excellent |
Critical Role in Copper Hydrometallurgy & Raffinate Loops
In copper heap leaching operations, dilute sulfuric acid solvent is irrigated over low-grade copper ore to dissolve copper minerals. The resulting copper-rich solution is run through a solvent extraction (SX-EW) circuit using **raffinate** (acidic recycled solution).
Because the raffinate and leaching solutions consist of **sulfuric acid diluted with water and active mineral impurities**, standard carbon steels or stainless 316 valves dissolve or suffer severe pitting due to the low pH. Supreme Valves' **Alloy 20 dual-plate check valves and gate valves** offer complete resistance to this corrosive dissolution, ensuring that leach lines stay pressurized and copper extraction circuits run with zero downtime.
Technical Specifications & Material Standard Codes
| Specification Parameter | ASTM Standard / Compliance Metric |
|---|---|
| Cast Body Alloys | ASTM A351 Grade CN7M (Austenitic stabilized Alloy 20) |
| Forged / Trim Fittings | ASTM B462 (Forgings) / ASTM B473 (Barstock / Stem) |
| Stabilization Element | Columbium (Columbium/Niobium) - prevents intergranular cracking |
| Pressure Ratings | ASME B16.34 Class 150, Class 300, Class 600 |
| Wall Thickness Design | API 600 / API 603 / ASME B16.34 standard limits |
| Mandatory Testing | ASME B16.34 wall verification, API 598 shell hydro, seat leakage tests |
| Sulfide Stress Cracking | Fully compliant with NACE MR0175 / ISO 15156 |
| Fasteners / Bolting | ASTM A193 Grade B8M (SS316 stud) / ASTM A194 Grade 8M (Nuts) |
USA & Global B2B Request for Quote
Are you a procurement manager or design engineer looking for high-quality Alloy 20 check, gate, or ball valves? Submit your inquiry details below. We accommodate small quantities (including Qty 1 sample orders for USA projects) and export door-to-door globally.
Our B2B Commitments:
- **Proforma Invoice (PI) & banking wire transfer details in US Dollars**
- Direct air-cargo routing to USA sites (DAP Saint George, Utah, Phoenix, Tucson, Salt Lake City)
- ISO 10204 3.1 Material Test Certificate (MTC) package with each shipment