Performance and Precautions for Freeman Valve's ASTM A182 F51 Check Valve, and The Differences Between ASTM A182 F51 Check Valve and ASTM A995 Gr. 4A Check Valve
ASTM A182 F51, a forged version of 2205 duplex stainless steel, is an ideal check valve material for chloride-containing environments due to its excellent resistance to chloride ion corrosion. The following focuses on the core advantages and usage precautions of this model of check valve manufactured by Freeman Valve.
1. Core Advantages of Freeman Valve's ASTM A182 F51 check valve in Resisting Chloride Ion Corrosion
1.1 Excellent Resistance to Chloride Stress Corrosion Cracking (SCC)
This is the most crucial advantage of this check valve model and the key reason why it replaces traditional F316L check valve. Mechanistically, ASTM A182 F51 employs a ferrite (F) + austenite (A) duplex microstructure, completely breaking the SCC sensitivity mechanism of pure austenitic stainless steel under the coupling effect of "chloride ions + tensile stress." The ferrite phase effectively inhibits crack propagation, significantly improving the check valve's SCC threshold.
In practical applications, this check valve exhibits significantly superior corrosion resistance compared to austenitic stainless-steel castings such as F304 and F316L in typical SCC environments, including seawater, brine, and chlorinated process media. It can maintain stable operation for extended periods under conditions where traditional austenitic stainless-steel check valve frequently fail, greatly improving equipment reliability.
1.2 Excellent Resistance to Pitting and Crevice Corrosion
This advantage stems from its well-designed alloy composition: ASTM A182 F51 contains approximately 22% chromium (Cr), 3% molybdenum (Mo), and 0.10–0.30% nitrogen (N), achieving a pitting corrosion resistance equivalent (PREN) of 32–38, far exceeding that of F316L (PREN≈25).
The synergistic effect of Mo and N is particularly crucial, giving it extremely strong resistance to pitting and crevice corrosion in neutral and weakly acidic media containing chloride ions (such as seawater and chloride solutions). Especially suitable for complex casting structures with gaps, easily deposited media, and localized stagnation in check valve internal flow channels and flange sealing surfaces, reducing the risk of localized corrosion failure at its source.
1.3 Excellent Resistance to Uniform Corrosion
In neutral, weakly alkaline, and weakly acidic environments containing chloride ions, the high Cr content in ASTM A182 F51 check valve forms a stable passivation film with an extremely low overall uniform corrosion rate, far superior to ordinary carbon steel and low-alloy cast iron check valve. This effectively resists the overall erosion of the check valve body by chloride ions, extending the check valve's service life.
2. Precautions for Using ASTM A182 F51 check valve
2.1 Temperature Limits
The recommended long-term operating temperature for this check valve is ≤300℃. Exceeding this temperature will significantly reduce the stability of its duplex structure, accelerate the precipitation of intermetallic phases, and significantly deteriorate its resistance to chloride ion corrosion. Especially under the combined conditions of "high temperature + high chloride," its corrosion resistance is far inferior to that of super duplex steel castings (such as ASTM A995 5A/6A) or nickel-based alloys, requiring material upgrades based on the operating conditions.
2.2 Concentration/Pressure Limitations
Use in extreme corrosive conditions should be avoided: Environments with extremely high concentrations of chloride ions, high temperature and pressure, or strong acidic chlorides (such as high-temperature concentrated hydrochloric acid, high-chlorine and high-pressure oil and gas) should be avoided. ASTM A182 F51 check valve have insufficient resistance to pitting corrosion and SCC, and are prone to rapid corrosion failure. Appropriate selection based on operating conditions is necessary.
3. Core Differences Between ASTM A182 F51 check valve and ASTM A995 Gr. 4A check valve
Both belong to the 2205 duplex stainless steel system. The core difference lies only in the manufacturing process and corresponding standards, as follows:
• ASTM A995 Gr. 4A: Follows the ASTM A995 standard and is a cast version of 2205 duplex stainless steel, mainly used for check valve components with complex structures (such as check valve bodies and covers).
• ASTM A182 F51: Follows the ASTM A182 standard and is a forged version of 2205 duplex stainless steel, emphasizing high strength and consistent performance. It is mostly used for check valve forgings with higher mechanical performance requirements.
Design Standard of F51 Check Valve:
Design Acc. to ASME B16.34 (ANSI Standard F51 Check Valve);
Design Acc. to EN-12516-1/2 (EN Standard F51 Check Valve, DIN Standard F51 Check Valve).
Test Standard of F51 Check Valve:
Test Acc. to API 598 (ANSI Standard F51 Check Valve);
Test Acc. to EN 12266-1/2 (EN Standard F51 Check Valve, DIN Standard F51 Check Valve).
Surface Finishing of F51 Check Valve:
All F51 Check Valve surface is finely machined to achieve the required roughness and conforms to standard MSS SP-110.
Size of F51 Check Valve:
From DN1/4’’ to 48’’ (ANSI Standard F51 Check Valve);
From DN8 to DN1200 (EN Standard F51 Check Valve, DIN Standard F51 Check Valve).
Face to Face of F51 Check Valve:
Face to Face Acc. to ASME B16.10 (ANSI Standard F51 Check Valve);
Face to Face Acc. to EN 558-1 (EN Standard F51 Check Valve, DIN Standard F51 Check Valve).
Pressure Rating of F51 Check Valve:
ANSI Class 150 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 300 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 600 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 800 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 900 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 1500 F51 Check Valve (ANSI Standard F51 Check Valve);
ANSI Class 2500 F51 Check Valve (ANSI Standard F51 Check Valve);
EN 1092 PN 16 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 25 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 40 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 63 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 100 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 160 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 250 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 320 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve);
EN 1092 PN 400 F51 Check Valve (EN Standard F51 Check Valve, DIN Standard F51 Check Valve).
Working Temperature of F51 Check Valve:
Please refer to the "Temperature and Pressure Curve of F51 Check Valve" for temperature and pressure changes.
Ends Connection of F51 Check Valve:
ANSI Flange Ends F51 Check Valve;
ANSI Integral Flange Ends F51 Check Valve;
ANSI Welded Flange Ends F51 Check Valve;
Butt Weld (ASME B16.25) Ends F51 Check Valve;
Butt Weld x ANSI Flange Ends F51 Check Valve;
EN 1092 Flange Ends F51 Check Valve;
EN 1092 Integral Flange Ends F51 Check Valve;
EN 1092 Welded Flange Ends F51 Check Valve;
Butt Weld (EN 12627) Ends F51 Check Valve;
Butt Weld (ISO 1127) Ends F51 Check Valve;
Butt Weld x EN 1092 Flange Ends F51 Check Valve;
Male NPT (ASME B1.20.1) Ends F51 Check Valve;
Male BSPP (ISO 228-1) Ends F51 Check Valve;
Male BSPT (ISO 7-1) Ends F51 Check Valve;
Male NPT x Female NPT Ends F51 Check Valve;
Male BSPP x Female BSPP Ends F51 Check Valve;
Male BSPT x Female BSPT Ends F51 Check Valve;
Male NPT x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Male BSPP x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Male BSPT x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Female NPT (ASME B1.20.1) Ends F51 Check Valve;
Female BSPP (ISO 228-1) Ends F51 Check Valve;
Female BSPT (ISO 7-1) Ends F51 Check Valve;
Socket Weld (ASME B16.11) Ends F51 Check Valve;
Socket Weld (EN 12760) Ends F51 Check Valve;
Female NPT x Socket Weld Ends F51 Check Valve;
Female BSPP x Socket Weld Ends F51 Check Valve;
Female BSPT x Socket Weld Ends F51 Check Valve;
Butt Weld (ASME B16.25) Ends F51 Check Valve;
Butt Weld (EN 12627) Ends F51 Check Valve;
Female NPT x Butt Weld Ends F51 Check Valve;
Female BSPP x Butt Weld Ends F51 Check Valve;
Female BSPT x Butt Weld Ends F51 Check Valve;
Female NPT x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Female BSPP x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Female BSPT x Long Butt Weld (+100 mm) Ends F51 Check Valve;
Long Butt Weld (+100 mm Weld Stub) Ends F51 Check Valve.
CE Marking of F51 Check Valve:
CE Marking is Available to F51 Check Valve with a Diameter of DN32 or Larger.
Chemical Composition of F51 Check Valve:
For the Chemical Composition of F51 Check Valve, please refer to EN 10204 Type 3.1 certificate.
Mechanical Properties of F51 Check Valve:
For the Mechanical Properties of F51 Check Valve, please refer to EN 10204 Type 3.1 certificate.
Certificate of F51 Check Valve:
All F51 Check Valve will be delivered with EN 10204 Type 3.1 Certificate.
Approvals of F51 Check Valve:
MSS SP-110 Certified of F51 Check Valve;
NACE MR 0175 Certified of F51 Check Valve
API 607 Fire Safe Certified of F51 Check Valve;
ISO 9001 Certified of F51 Check Valve;
PED Certified of F51 Check Valve.
Available Upon Request of F51 Check Valve:
NACE MR0175 is available upon request of F51 Check Valve;
ATEX is available upon request of F51 Check Valve;
TA-LUFT is available upon request of F51 Check Valve;
SIL is available upon request of F51 Check Valve;
Degreasing is available upon request of F51 Check Valve;
Fire Safe is available upon request of F51 Check Valve;
Stem Extension is available upon request of F51 Check Valve;
Double Block and Bleed is available upon request of F51 Check Valve.