UNS S38815, also known as Zecor-Z or 310M, is a duplex stainless steel that combines a dual-phase structure of austenite and ferrite, offering a unique balance of properties. Freeman Valve's UNS S38815 ANSI globe valve offer the following advantages:

1.1 Excellent Corrosion Resistance:

① Freeman Valve's UNS S38815 ANSI globe valve significantly outperform 304/316 austenitic stainless steels in pitting and crevice corrosion resistance in chloride environments (such as seawater and brine).

② Freeman Valve's UNS S38815 ANSI globe valve significantly outperform ordinary austenitic stainless steels in stress corrosion cracking (SCC).

③ Freeman Valve's UNS S38815 ANSI globe valve exhibit excellent resistance to media such as dilute sulfuric acid and organic acids.

1.2 Fatigue and Wear Resistance:

The presence of ferrite in Freeman Valve's UNS S38815 ANSI globe valve enhances wear resistance, making them suitable for dynamic load environments.

2. When using UNS S38815 ANSI globe valve, please note the following:

2.1 UNS S38815 ANSI globe valve has limited low-temperature toughness: The ferrite phase may become brittle at extremely low temperatures, making them unsuitable for ultra-low-temperature environments such as liquid nitrogen (austenitic stainless steel is preferred).

2.2 UNS S38815 ANSI globe valve is sensitive to heat treatment: Prolonged heating at 300-900°C may cause precipitation of sigma phase or carbides, resulting in brittleness or decreased corrosion resistance. Strict control of the heat treatment process is required.

2.3 UNS S38815 valve application temperature limit: Long-term operating temperatures generally do not exceed 250-300°C. Phase transformation may occur at high temperatures.

2.4 UNS S38815 ANSI globe valve should avoid use in environments with strong reducing acids (such as hydrochloric acid).

3 Key Application Areas for Freeman Valve's UNS S38815 ANSI globe valve:

3.1 Freeman Valve's UNS S38815 ANSI globe valve is widely used in the oil and gas industry, for example, in chloride-resistant systems such as submarine pipelines and downhole equipment operating in acidic environments (including H₂S/CO₂).

3.2 Freeman Valve's UNS S38815 ANSI globe valve is widely used in the chemical and petrochemical industries, for example, in reactors, heat exchangers, storage tanks (especially those containing chloride ions or acidic media), and in chemical equipment such as sulfuric acid and phosphoric acid.

3.3 Freeman Valve's UNS S38815 ANSI globe valve is widely used in seawater treatment, for example, in desalination plants, condensers, and seawater pumps.

3.4 Freeman Valve's UNS S38815 ANSI globe valve is widely used in the pulp and paper industry, for example, in high-chloride environment equipment in bleaching plants.

3.5 Freeman Valve's UNS S38815 ANSI globe valve has been widely used in the energy and environmental protection sectors, such as flue gas desulfurization (FGD) systems and wastewater treatment equipment.

4 Conclusion:

UNS S38815 ANSI globe valve is suitable for moderately harsh environments requiring a balance of strength, corrosion resistance, and cost, and perform particularly well in the presence of chloride ions.

Analysis of the Advantages and Disadvantages of Freeman Valve's UNS S38815 ANSI globe valve in Concentrated Sulfuric Acid Corrosion

1 Advantages of the UNS S38815 ANSI globe valve in Concentrated Sulfuric Acid Corrosion:

1.1 Resistance of the UNS S38815 ANSI globe valve in Moderately Concentrated Sulfuric Acid (80%-95%): In concentrated sulfuric acid (above 90%) at room temperature or slightly elevated temperatures (<50°C), a passive film forms on the surface of the UNS S38815 valve, exhibiting excellent corrosion resistance. Furthermore, the balanced duplex structure (austenite + ferrite) of the UNS S38815 ANSI globe valve provides strong resistance to uniform corrosion.

1.2 Stability of the UNS S38815 ANSI globe valve in Oxidizing Environments: If the concentrated sulfuric acid contains oxidizing impurities (such as dissolved oxygen, Fe₃⁺, Cu₂⁺, etc.), the passivation ability of the UNS S38815 ANSI globe valve is enhanced, further reducing the corrosion rate.

1.3 Freeman Valve's UNS S38815 ANSI globe valve is resistant to stress corrosion cracking (SCC). In sulfuric acid environments containing trace amounts of chloride ions (such as industrial sulfuric acid), UNS S38815 ANSI globe valve exhibit significantly better SCC resistance than austenitic stainless steels (such as 316L).

2 Disadvantages of UNS S38815 ANSI globe valve in their corrosion resistance to concentrated sulfuric acid:

2.1 High corrosion risk for UNS S38815 ANSI globe valve in reducing concentrated sulfuric acid: At high temperatures (>50°C) or in reducing concentrated sulfuric acid (such as low-purity sulfuric acid containing H₂S, SO₂, etc.), the passive film on UNS S38815 ANSI globe valve is easily destroyed, causing a sharp increase in corrosion rate. Furthermore, the ferrite phase may corrode preferentially, leading to localized pitting or selective dissolution.

2.2 Limitations of UNS S38815 ANSI globe valve for Low-Concentration Sulfuric Acid (<80%): Dilute sulfuric acid (especially <50%) is more corrosive to UNS S38815 ANSI globe valve. In these cases, higher alloy materials (such as Hastelloy C-276 or PTFE-lined equipment) are required.

2.3 Temperature Sensitivity of UNS S38815 ANSI globe valve: Long-term use of UNS S38815 ANSI globe valve in concentrated sulfuric acid at temperatures above 60°C may cause intergranular corrosion or sigma phase precipitation, requiring strict temperature limits.

2.4 Impact of Chloride Ion Impurities on UNS S38815 ANSI globe valve: Chloride ions (Cl⁻) in concentrated sulfuric acid may cause pitting and crevice corrosion, especially in stagnant areas.

Corrosion Resistance Comparison of Hastelloy C-276 ANSI globe valve and UNS S38815 ANSI globe valve

1 Advantages of Hastelloy C-276 ANSI globe valve:

1.1 Hastelloy C-276 ANSI globe valve is resistant to corrosion in concentrated sulfuric acid at all concentrations: From dilute sulfuric acid (<10%) to fuming sulfuric acid (>100%), they perform excellently across a wide concentration range, particularly at high temperatures (up to the boiling point) and in reducing environments.

1.2 Hastelloy C-276 ANSI globe valve is resistant to localized corrosion: Hastelloy C-276 ANSI globe valve is virtually unaffected by pitting and crevice corrosion, even in the presence of chloride ions (Cl⁻) or in alternating redox media.

1.3 High-temperature adaptability of Hastelloy C-276 ANSI globe valve: Hastelloy C-276 ANSI globe valve can operate at temperatures exceeding 200°C (in concentrated sulfuric acid) for extended periods without the risk of sigma-phase embrittlement.

2. Disadvantages of Hastelloy C-276 ANSI globe valve:

Overdesign Risk: Performance is redundant in ambient temperature oxidizing concentrated sulfuric acid (>90%), resulting in a low cost-performance ratio.

3. Advantages of UNS S38815 ANSI globe valve:

UNS S38815 ANSI globe valve is resistant to medium- and high-concentration oxidizing acids: UNS S38815 ANSI globe valve exhibit excellent corrosion resistance in ambient temperature (~50°C) and 90%-95% concentrated sulfuric acid (containing oxidizing media such as Fe₃⁺ and Cu₂⁺), and their cost is significantly lower than C-276.

4 Disadvantages of UNS S38815 ANSI globe valve: Concentration and Temperature Sensitivity:

4.1 UNS S38815 ANSI globe valve has a high corrosion rate in dilute sulfuric acid (<80%);

4.2 UNS S38815 ANSI globe valve is susceptible to damage to the passivation film in high temperatures (>60°C) or in reducing acids (containing H₂S/SO₂);

4.3 UNS S38815 ANSI globe valve may cause localized corrosion in media containing chloride ions.

5 Application Selection

5.1 Situations Where Hastelloy C-276 ANSI globe valve is Preferred:

① High-temperature concentrated sulfuric acid (e.g., concentration processes >80°C, waste acid recovery);

② Reducing/impurity environments (industrial sulfuric acid containing H₂S, SO₂, and Cl⁻);

③ Critical equipment (e.g., reactors and heat exchangers requiring long life and zero leakage).

5.2 Preferred Situations for UNS S38815 ANSI globe valve:

① Normal/low-temperature oxidizing concentrated sulfuric acid (e.g., 90%-95% sulfuric acid storage tanks and pipelines).

② Budget limitations and mild corrosion conditions (regular inspection and maintenance required).

③ Requirement of high-strength and lightweight structural components.

6 Summary

6.1 Hastelloy C-276 ANSI globe valve is the "ultimate solution" for concentrated sulfuric acid (especially high-temperature, reducing, and impurity-laden), but they are costly.

6.2 UNS S38815 ANSI globe valve is an economical option, limited to oxidizing, medium-low-temperature, and high-concentration sulfuric acid, requiring strict monitoring of environmental parameters.

Key Decision: Evaluate the sulfuric acid's purity, temperature, redox properties, and equipment life requirements, and verify through corrosion coupon testing if necessary.

Design Standard of UNS S38815 Globe Valve:

Design Acc. to ASME B16.34 (ANSI Standard UNS S38815 Globe Valve);

Design Acc. to EN-12516-1/2 (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve).

Test Standard of UNS S38815 Globe Valve:

Test Acc. to API 598 (ANSI Standard UNS S38815 Globe Valve);

Test Acc. to EN 12266-1/2 (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve).

Surface Finishing of UNS S38815 Globe Valve:

All UNS S38815 Globe Valve surface is finely machined to achieve the required roughness and conforms to standard MSS SP-55.

Size of UNS S38815 Globe Valve:

From DN1/4’’ to 48’’ (ANSI Standard UNS S38815 Globe Valve);

From DN8 to DN1200 (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve).

Face to Face of UNS S38815 Globe Valve:

Face to Face Acc. to ASME B16.10 (ANSI Standard UNS S38815 Globe Valve);

Face to Face Acc. to EN 558-1 (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve).

Pressure Rating of UNS S38815 Globe Valve:

ANSI Class 150 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 300 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 600 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 800 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 900 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 1500 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

ANSI Class 2500 UNS S38815 Globe Valve (ANSI Standard UNS S38815 Globe Valve);

EN 1092 PN 16 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 25 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 40 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 63 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 100 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 160 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 250 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 320 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve);

EN 1092 PN 400 UNS S38815 Globe Valve (EN Standard UNS S38815 Globe Valve, DIN Standard UNS S38815 Globe Valve).

Working Temperature of UNS S38815 Globe Valve:

Please refer to the "Temperature and Pressure Curve of UNS S38815 Globe Valve" for temperature and pressure changes.

Ends Connection of UNS S38815 Globe Valve:

ANSI Flange Ends UNS S38815 Globe Valve;

ANSI Integral Flange Ends UNS S38815 Globe Valve;

ANSI Welded Flange Ends UNS S38815 Globe Valve;

Butt Weld (ASME B16.25) Ends UNS S38815 Globe Valve;

Butt Weld x ANSI Flange Ends UNS S38815 Globe Valve;

EN 1092 Flange Ends UNS S38815 Globe Valve;

EN 1092 Integral Flange Ends UNS S38815 Globe Valve;

EN 1092 Welded Flange Ends UNS S38815 Globe Valve;

Butt Weld (EN 12627) Ends UNS S38815 Globe Valve;

Butt Weld (ISO 1127) Ends UNS S38815 Globe Valve;

Butt Weld x EN 1092 Flange Ends UNS S38815 Globe Valve;

Male NPT (ASME B1.20.1) Ends UNS S38815 Globe Valve;

Male BSPP (ISO 228-1) Ends UNS S38815 Globe Valve;

Male BSPT (ISO 7-1) Ends UNS S38815 Globe Valve;

Male NPT x Female NPT Ends UNS S38815 Globe Valve;

Male BSPP x Female BSPP Ends UNS S38815 Globe Valve;

Male BSPT x Female BSPT Ends UNS S38815 Globe Valve;

Male NPT x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Male BSPP x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Male BSPT x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Female NPT (ASME B1.20.1) Ends UNS S38815 Globe Valve;

Female BSPP (ISO 228-1) Ends UNS S38815 Globe Valve;

Female BSPT (ISO 7-1) Ends UNS S38815 Globe Valve;

Socket Weld (ASME B16.11) Ends UNS S38815 Globe Valve;

Socket Weld (EN 12760) Ends UNS S38815 Globe Valve;

Female NPT x Socket Weld Ends UNS S38815 Globe Valve;

Female BSPP x Socket Weld Ends UNS S38815 Globe Valve;

Female BSPT x Socket Weld Ends UNS S38815 Globe Valve;

Butt Weld (ASME B16.25) Ends UNS S38815 Globe Valve;

Butt Weld (EN 12627) Ends UNS S38815 Globe Valve;

Female NPT x Butt Weld Ends UNS S38815 Globe Valve;

Female BSPP x Butt Weld Ends UNS S38815 Globe Valve;

Female BSPT x Butt Weld Ends UNS S38815 Globe Valve;

Female NPT x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Female BSPP x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Female BSPT x Long Butt Weld (+100 mm) Ends UNS S38815 Globe Valve;

Long Butt Weld (+100 mm Weld Stub) Ends UNS S38815 Globe Valve.

CE Marking of UNS S38815 Globe Valve:

CE Marking is Available to UNS S38815 Globe Valve with a Diameter of DN32 or Larger.

Chemical Composition of UNS S38815 Globe Valve:

For the Chemical Composition of UNS S38815 Globe Valve, please refer to EN 10204 Type 3.1 certificate.

Mechanical Properties of UNS S38815 Globe Valve:

For the Mechanical Properties of UNS S38815 Globe Valve, please refer to EN 10204 Type 3.1 certificate.

Certificate of UNS S38815 Globe Valve:

All UNS S38815 Globe Valve will be delivered with EN 10204 Type 3.1 Certificate.

Approvals of UNS S38815 Globe Valve:

MSS SP-110 Certified of UNS S38815 Globe Valve;

NACE MR 0175 Certified of UNS S38815 Globe Valve

API 607 Fire Safe Certified of UNS S38815 Globe Valve;

ISO 9001 Certified of UNS S38815 Globe Valve;

PED Certified of UNS S38815 Globe Valve.

Available Upon Request of UNS S38815 Globe Valve:

NACE MR0175 is available upon request of UNS S38815 Globe Valve;

ATEX is available upon request of UNS S38815 Globe Valve;

TA-LUFT is available upon request of UNS S38815 Globe Valve;

SIL is available upon request of UNS S38815 Globe Valve;

Degreasing is available upon request of UNS S38815 Globe Valve;

Fire Safe is available upon request of UNS S38815 Globe Valve;

Stem Extension is available upon request of UNS S38815 Globe Valve;

Double Block and Bleed is available upon request of UNS S38815 Globe Valve.