1. What is 904L Stainless Steel?
904L stainless steel (UNS N08904/EN 1.4539) is an ultra-low carbon, high-alloy austenitic stainless steel. Its core advantage is its extremely strong corrosion resistance in harsh environments such as dilute sulfuric acid and chloride-containing media, and it is also easy to process and weld.
2. Freeman Valve's 904L stainless steel ANSI check valve has the following advantages:
2.1 Excellent Corrosion Resistance:
a. Freeman Valve's 904L stainless steel ANSI check valve has high molybdenum (Mo: 4~5%) and copper (Cu: 1~2%) content, which significantly improves their resistance to reducing acids (such as sulfuric acid and phosphoric acid) and halides (such as chloride ions);
b. Freeman Valve's 904L stainless steel ANSI check valve perform excellently in media such as dilute sulfuric acid, boiling phosphoric acid, and organic acids, exhibiting outstanding resistance to pitting and crevice corrosion.
2.2 Excellent resistance to stress corrosion cracking (SCC): Freeman Valve's 904L stainless steel ANSI check valve is 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.
2.3 High-temperature adaptability: Freeman Valve's 904L stainless steel ANSI check valve maintain stability at high temperatures and can withstand short-term environments up to approximately 400°C.
3. The following issues should be noted when using 904L stainless steel ANSI check valve:
3.1 Not suitable for strong oxidizing environments: In strong oxidizing acids such as nitric acid, the corrosion resistance of 904L stainless steel ANSI check valve is actually inferior to that of 304L or 316L ANSI check valve with lower molybdenum content.
3.2 Sensitivity issues: Improper welding or heat treatment can easily lead to carbide precipitation, requiring solution treatment (rapid cooling at 1100~1150°C) to restore performance.
4. Classic Applications of Freeman Valve's 904L Stainless Steel ANSI check valve:
4.1 Freeman Valve's 904L stainless steel ANSI check valve is widely used in sulfuric acid environments. Examples include: dilute sulfuric acid storage tanks, pipelines, and heat exchangers (especially for sulfuric acid concentrations ≤10%, exhibiting excellent corrosion resistance at temperatures ≤40℃).
4.2 Freeman Valve's 904L stainless steel ANSI check valve is widely used in chloride-containing systems. Examples include: seawater cooling systems, salt chemical evaporators, and chlorination reactor linings.
4.3 Freeman Valve's 904L stainless steel ANSI check valve is widely used in organic acid processing. Examples include: acetic acid and formic acid production equipment, preventing localized corrosion.
4.4 Freeman Valve's 904L stainless steel ANSI check valve is widely used in environmental protection and hydrometallurgical fields. Examples include: flue gas desulfurization (FGD) system components and acidic wastewater treatment equipment.
4.5 Freeman Valve's 904L stainless steel ANSI check valve is widely used in PTA (purified terephthalic acid) production. For example: crystallizers and condensers used in high-temperature acetic acid media.
4.6 Freeman Valve's 904L stainless steel ANSI check valve is widely used in the pharmaceutical industry. For example: reaction vessels and pipelines for high-purity pharmaceuticals (resistant to cleaning agent corrosion).
Differences between 904L and 2205 stainless steel ANSI check valve in resisting chloride ion corrosion
1. Different emphasis on pitting/crevice corrosion resistance:
1.1 The pitting equivalent value (PREN≈33-35) of 2205 ANSI check valve is higher than that of 904L ANSI check valve (PREN≈32-34), and the strengthening effect of nitrogen makes it more resistant to pitting corrosion in high-concentration, high-temperature chloride ion environments (such as high-chlorinated brine in deep well oil production, seawater above 60℃).
1.2 The high nickel + copper content of 904L ANSI check valve results in a passivation film stability far exceeding that of 2205 in chloride-containing reducing media (such as dilute sulfuric acid + chloride ion mixed systems), and avoids the phase imbalance problem of duplex steel. 2. Differences in Stress Corrosion Cracking (SCC) Resistance:
2.1 Stress corrosion cracking under chloride ion conditions is a common failure mode for austenitic stainless steel 2205 ANSI check valve, but the high nickel content of 904L ANSI check valve significantly reduces this susceptibility. 2205 ANSI check valve also exhibit better SCC resistance than ordinary austenitic steels such as 316L, but under the same chloride ion concentration and stress conditions, their long-term stability is slightly lower than that of 904L ANSI check valve.
3. Differences in Process and Operating Condition Matching:
3.1 904L ANSI check valve require no heat treatment after welding and has good low-temperature toughness, making them suitable for polar and marine environments.
3.2 2205 ANSI check valve 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 ANSI check valve) makes them more suitable for high-pressure + high-chlorine composite operating conditions (such as high-pressure seawater pipelines).
Design Standard of 904L Swing Check Valve:
Design Acc. to ASME B16.34 (ANSI Standard 904L Swing Check Valve);
Design Acc. to EN-12516-1/2 (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve).
Test Standard of 904L Swing Check Valve:
Test Acc. to API 598 (ANSI Standard 904L Swing Check Valve);
Test Acc. to EN 12266-1/2 (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve).
Surface Finishing of 904L Swing Check Valve:
All 904L Swing Check Valve surface is finely machined to achieve the required roughness and conforms to standard MSS SP-110.
Size of 904L Swing Check Valve:
From DN1/4’’ to 48’’ (ANSI Standard 904L Swing Check Valve);
From DN8 to DN1200 (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve).
Face to Face of 904L Swing Check Valve:
Face to Face Acc. to ASME B16.10 (ANSI Standard 904L Swing Check Valve);
Face to Face Acc. to EN 558-1 (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve).
Pressure Rating of 904L Swing Check Valve:
ANSI Class 150 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 300 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 600 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 800 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 900 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 1500 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
ANSI Class 2500 904L Swing Check Valve (ANSI Standard 904L Swing Check Valve);
EN 1092 PN 16 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 25 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 40 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 63 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 100 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 160 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 250 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 320 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve);
EN 1092 PN 400 904L Swing Check Valve (EN Standard 904L Swing Check Valve, DIN Standard 904L Swing Check Valve).
Working Temperature of 904L Swing Check Valve:
Please refer to the "Temperature and Pressure Curve of 904L Swing Check Valve" for temperature and pressure changes.
Ends Connection of 904L Swing Check Valve:
ANSI Flange Ends 904L Swing Check Valve;
ANSI Integral Flange Ends 904L Swing Check Valve;
ANSI Welded Flange Ends 904L Swing Check Valve;
Butt Weld (ASME B16.25) Ends 904L Swing Check Valve;
Butt Weld x ANSI Flange Ends 904L Swing Check Valve;
EN 1092 Flange Ends 904L Swing Check Valve;
EN 1092 Integral Flange Ends 904L Swing Check Valve;
EN 1092 Welded Flange Ends 904L Swing Check Valve;
Butt Weld (EN 12627) Ends 904L Swing Check Valve;
Butt Weld (ISO 1127) Ends 904L Swing Check Valve;
Butt Weld x EN 1092 Flange Ends 904L Swing Check Valve;
Male NPT (ASME B1.20.1) Ends 904L Swing Check Valve;
Male BSPP (ISO 228-1) Ends 904L Swing Check Valve;
Male BSPT (ISO 7-1) Ends 904L Swing Check Valve;
Male NPT x Female NPT Ends 904L Swing Check Valve;
Male BSPP x Female BSPP Ends 904L Swing Check Valve;
Male BSPT x Female BSPT Ends 904L Swing Check Valve;
Male NPT x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Male BSPP x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Male BSPT x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Female NPT (ASME B1.20.1) Ends 904L Swing Check Valve;
Female BSPP (ISO 228-1) Ends 904L Swing Check Valve;
Female BSPT (ISO 7-1) Ends 904L Swing Check Valve;
Socket Weld (ASME B16.11) Ends 904L Swing Check Valve;
Socket Weld (EN 12760) Ends 904L Swing Check Valve;
Female NPT x Socket Weld Ends 904L Swing Check Valve;
Female BSPP x Socket Weld Ends 904L Swing Check Valve;
Female BSPT x Socket Weld Ends 904L Swing Check Valve;
Butt Weld (ASME B16.25) Ends 904L Swing Check Valve;
Butt Weld (EN 12627) Ends 904L Swing Check Valve;
Female NPT x Butt Weld Ends 904L Swing Check Valve;
Female BSPP x Butt Weld Ends 904L Swing Check Valve;
Female BSPT x Butt Weld Ends 904L Swing Check Valve;
Female NPT x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Female BSPP x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Female BSPT x Long Butt Weld (+100 mm) Ends 904L Swing Check Valve;
Long Butt Weld (+100 mm Weld Stub) Ends 904L Swing Check Valve.
CE Marking of 904L Swing Check Valve:
CE Marking is Available to 904L Swing Check Valve with a Diameter of DN32 or Larger.
Chemical Composition of 904L Swing Check Valve:
For the Chemical Composition of 904L Swing Check Valve, please refer to EN 10204 Type 3.1 certificate.
Mechanical Properties of 904L Swing Check Valve:
For the Mechanical Properties of 904L Swing Check Valve, please refer to EN 10204 Type 3.1 certificate.
Certificate of 904L Swing Check Valve:
All 904L Swing Check Valve will be delivered with EN 10204 Type 3.1 Certificate.
Approvals of 904L Swing Check Valve:
MSS SP-110 Certified of 904L Swing Check Valve;
NACE MR 0175 Certified of 904L Swing Check Valve
API 607 Fire Safe Certified of 904L Swing Check Valve;
ISO 9001 Certified of 904L Swing Check Valve;
PED Certified of 904L Swing Check Valve.
Available Upon Request of 904L Swing Check Valve:
NACE MR0175 is available upon request of 904L Swing Check Valve;
ATEX is available upon request of 904L Swing Check Valve;
TA-LUFT is available upon request of 904L Swing Check Valve;
SIL is available upon request of 904L Swing Check Valve;
Degreasing is available upon request of 904L Swing Check Valve;
Fire Safe is available upon request of 904L Swing Check Valve;
Stem Extension is available upon request of 904L Swing Check Valve;
Double Block and Bleed is available upon request of 904L Swing Check Valve.
Lift Type (Piston Type)