904L is an ultra-low carbon, high-alloy austenitic stainless steel. The core advantage of 904L safety valves is their exceptional corrosion resistance in harsh environments such as dilute sulfuric acid and chloride-containing media, and their ease of machining and welding.
① Freeman Valve's 904L safety valves have high molybdenum (Mo: 4~5%) and copper (Cu: 1~2%) content, significantly improving their resistance to reducing acids (such as sulfuric acid and phosphoric acid) and halides (such as chloride ions);
② Freeman Valve's 904L safety valves perform excellently in media such as dilute sulfuric acid, boiling phosphoric acid, and organic acids, exhibiting outstanding resistance to pitting and crevice corrosion.
Freeman Valve's 904L safety valves are suitable for environments containing chloride ions (such as seawater and chloride solutions), exhibiting superior resistance to stress corrosion cracking compared to conventional austenitic stainless steels.
Freeman Valve's 904L safety valves maintain stability at high temperatures and can withstand short-term environments up to approximately 400°C.
In strong oxidizing acids such as nitric acid, 904L safety valves actually have lower corrosion resistance than 304L or 316L valves with lower molybdenum content.
Improper welding or heat treatment of 904L safety valves can easily lead to carbide precipitation, requiring solution treatment (rapid cooling at 1100~1150°C) to restore performance.
For example: dilute sulfuric acid storage tanks, pipelines, heat exchangers (especially for sulfuric acid with a concentration ≤10%, exhibiting excellent corrosion resistance at temperatures ≤40℃).
For example: seawater cooling systems, salt chemical evaporators, chlorination reactor linings.
For example: acetic acid and formic acid production equipment, preventing localized corrosion.
For example: flue gas desulfurization (FGD) system components, acidic wastewater treatment equipment.
For example: crystallizers and condensers used in high-temperature acetic acid media.
For example: reaction vessels and pipelines for high-purity pharmaceuticals (resistant to cleaning agent corrosion).
① The pitting equivalent value (PREN≈33-35) of the 2205 safety valves is higher than that of the 904L safety valves (PREN≈32-34), and the nitrogen content further enhances its resistance to pitting corrosion in high-concentration, high-temperature chloride ion environments (such as high-chlorinated brine in deep well oil production and seawater above 60℃).
② The high nickel + copper content of the 904L safety valves results in a passivation film with significantly greater stability than that of the 2205 safety valves in reducing media containing chloride (such as dilute sulfuric acid + chloride ion mixtures), without exhibiting the phase imbalance problem common in duplex steels.
① Stress corrosion cracking under chloride ion conditions is a common failure mode for 2205 safety valves, but the high nickel content of 904L safety valves significantly reduces this susceptibility. 2205 safety valves also exhibit better SCC resistance than ordinary austenitic steels such as 316L safety valves, but under the same chloride ion concentration and stress conditions, their long-term stability is slightly lower than that of 904L safety valves.
① 904L safety valves require no heat treatment after welding and have good low-temperature toughness, making them suitable for polar and marine environments.
② 2205 safety valves require controlled heat input during welding to avoid excessive ferrite content, but their high strength (tensile strength ≥620MPa, more than 1.2 times that of 904L safety valves) makes them more suitable for high-pressure + high-chlorine composite operating conditions (such as high-pressure seawater pipelines).
Design Standard of 904L Safety Valve:
Design Acc. to ASME B16.34 (ANSI Standard 904L Safety Valve);
Design Acc. to EN-12516-1/2 (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve).
Test Standard of 904L Safety Valve:
Test Acc. to API 598 (ANSI Standard 904L Safety Valve);
Test Acc. to EN 12266-1/2 (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve).
Surface Finishing of 904L Safety Valve:
All 904L Safety Valve surface is finely machined to achieve the required roughness and conforms to standard MSS SP-110.
Size of 904L Safety Valve:
From DN1/4’’ to 48’’ (ANSI Standard 904L Safety Valve);
From DN8 to DN1200 (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve).
Face to Face of 904L Safety Valve:
Face to Face Acc. to ASME B16.10 (ANSI Standard 904L Safety Valve);
Face to Face Acc. to EN 558-1 (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve).
Pressure Rating of 904L Safety Valve:
ANSI Class 150 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 300 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 600 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 800 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 900 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 1500 904L Safety Valve (ANSI Standard 904L Safety Valve);
ANSI Class 2500 904L Safety Valve (ANSI Standard 904L Safety Valve);
EN 1092 PN 16 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 25 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 40 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 63 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 100 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 160 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 250 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 320 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve);
EN 1092 PN 400 904L Safety Valve (EN Standard 904L Safety Valve, DIN Standard 904L Safety Valve).
Working Temperature of 904L Safety Valve:
Please refer to the "Temperature and Pressure Curve of 904L Safety Valve" for temperature and pressure changes.
Ends Connection of 904L Safety Valve:
ANSI Flange Ends 904L Safety Valve;
ANSI Integral Flange Ends 904L Safety Valve;
ANSI Welded Flange Ends 904L Safety Valve;
Butt Weld (ASME B16.25) Ends 904L Safety Valve;
Butt Weld x ANSI Flange Ends 904L Safety Valve;
EN 1092 Flange Ends 904L Safety Valve;
EN 1092 Integral Flange Ends 904L Safety Valve;
EN 1092 Welded Flange Ends 904L Safety Valve;
Butt Weld (EN 12627) Ends 904L Safety Valve;
Butt Weld (ISO 1127) Ends 904L Safety Valve;
Butt Weld x EN 1092 Flange Ends 904L Safety Valve;
Male NPT (ASME B1.20.1) Ends 904L Safety Valve;
Male BSPP (ISO 228-1) Ends 904L Safety Valve;
Male BSPT (ISO 7-1) Ends 904L Safety Valve;
Male NPT x Female NPT Ends 904L Safety Valve;
Male BSPP x Female BSPP Ends 904L Safety Valve;
Male BSPT x Female BSPT Ends 904L Safety Valve;
Male NPT x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Male BSPP x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Male BSPT x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Female NPT (ASME B1.20.1) Ends 904L Safety Valve;
Female BSPP (ISO 228-1) Ends 904L Safety Valve;
Female BSPT (ISO 7-1) Ends 904L Safety Valve;
Socket Weld (ASME B16.11) Ends 904L Safety Valve;
Socket Weld (EN 12760) Ends 904L Safety Valve;
Female NPT x Socket Weld Ends 904L Safety Valve;
Female BSPP x Socket Weld Ends 904L Safety Valve;
Female BSPT x Socket Weld Ends 904L Safety Valve;
Butt Weld (ASME B16.25) Ends 904L Safety Valve;
Butt Weld (EN 12627) Ends 904L Safety Valve;
Female NPT x Butt Weld Ends 904L Safety Valve;
Female BSPP x Butt Weld Ends 904L Safety Valve;
Female BSPT x Butt Weld Ends 904L Safety Valve;
Female NPT x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Female BSPP x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Female BSPT x Long Butt Weld (+100 mm) Ends 904L Safety Valve;
Long Butt Weld (+100 mm Weld Stub) Ends 904L Safety Valve.
CE Marking of 904L Safety Valve:
CE Marking is Available to 904L Safety Valve with a Diameter of DN32 or Larger.
Chemical Composition of 904L Safety Valve:
For the Chemical Composition of 904L Safety Valve, please refer to EN 10204 Type 3.1 certificate.
Mechanical Properties of 904L Safety Valve:
For the Mechanical Properties of 904L Safety Valve, please refer to EN 10204 Type 3.1 certificate.
Certificate of 904L Safety Valve:
All 904L Safety Valve will be delivered with EN 10204 Type 3.1 Certificate.
Approvals of 904L Safety Valve:
MSS SP-110 Certified of 904L Safety Valve;
NACE MR 0175 Certified of 904L Safety Valve
API 607 Fire Safe Certified of 904L Safety Valve;
ISO 9001 Certified of 904L Safety Valve;
PED Certified of 904L Safety Valve.
Available Upon Request of 904L Safety Valve:
NACE MR0175 is available upon request of 904L Safety Valve;
ATEX is available upon request of 904L Safety Valve;
TA-LUFT is available upon request of 904L Safety Valve;
SIL is available upon request of 904L Safety Valve;
Degreasing is available upon request of 904L Safety Valve;
Fire Safe is available upon request of 904L Safety Valve;
Stem Extension is available upon request of 904L Safety Valve;
Double Block and Bleed is available upon request of 904L Safety Valve.