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Intergranular Corrosion Resistance Stainless Steel 347H Slip On Flanges custom

Intergranular Corrosion Resistance Stainless Steel 347H Slip On Flanges Manufacturers

-- Steady & Reliable Manufacturer --

Stabilized Stainless Steel Flange Solutions

In high-temperature environments where sensitization can lead to catastrophic failure, our Stainless Steel 347H Slip On Flanges offer the ultimate protection. Grade 347H is a columbium-stabilized austenitic stainless steel specifically designed to prevent intergranular corrosion during long-term exposure in the chromium carbide precipitation range of 800°F to 1500°F (427°C to 816°C). As a specialized manufacturer, we focus on the "H" grade (High Carbon) variant, which provides higher creep strength and stress rupture properties than standard 347. The slip-on design allows for easy alignment on the pipe and dual welding points, making these flanges a reliable choice for critical thermal processing equipment. Our forging process ensures a uniform grain structure, maximizing the effectiveness of the niobium stabilization and ensuring your piping system remains ductile and crack-resistant under extreme thermal stress.

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347H Technical Specifications

ParameterSpecification Detail
Material GradeASTM A182 F347 / F347H (UNS S34709)
StandardsASME B16.5, DIN 2576, EN 1092-1
Stabilizing ElementColumbium (Niobium) + Tantalum
Pressure ClassesClass 150, 300, 600, 900, 1500
Size Range1/2" to 24" (DN15 - DN600)
Surface TreatmentPickled and Passivated

High-Temperature Chemical Applications

These 347H slip-on flanges are primarily utilized in oil refineries and petrochemical plants for high-temperature fluid catalytic cracking (FCC) units and hydro-desulfurization equipment. They are a critical component in the production of organic chemicals, particularly where heavy-duty heaters and heat exchangers are involved. In the power generation sector, they are used for steam boiler tubes and high-pressure steam pipes. Because of their excellent oxidation resistance and resistance to polythionic acid stress corrosion cracking, they are also favored in aircraft exhaust stacks and collector rings. Whether used in radiant heaters or high-temperature gaskets joints, 347H flanges provide a secure connection in environments where standard 304 or 316 stainless steels would suffer from intergranular attack at the weld zones.

Material Performance Advantages

  • Superior Creep Strength: The high carbon content (H-grade) ensures higher allowable stress at elevated temperatures.
  • Elimination of Sensitization: Niobium stabilization prevents chromium carbide precipitation, maintaining corrosion resistance after welding.
  • Excellent Ductility: Maintains toughness in high-heat service, reducing the risk of brittle fracture over years of operation.
  • Dual Fillet Welds: The slip-on design facilitates strong internal and external welds, ensuring a leak-proof terminal.

Trade & Export Support

We support payments via T/T, Irrevocable L/C at sight, and trade assurance. Since 347H is a specialized alloy, we provide 100% PMI (Positive Material Identification) testing to verify the niobium content before shipping. Each flange is coated with a light anti-rust oil or passivated and packed in seaworthy plywood cases with individual dividers to prevent face damage. We offer worldwide shipping via air for urgent refinery turnarounds and sea freight for new construction projects. Every order includes 3.1 Mill Test Certificates and intergranular corrosion test reports (ASTM A262 Practice E) upon request, ensuring complete compliance with global engineering standards and safety protocols.

  • Q: What is the main difference between 321 and 347H?
  • A: Both are stabilized, but 321 uses Titanium while 347 uses Niobium. 347H offers better creep resistance at temperatures above 1000°F compared to 321.
  • Q: Can 347H flanges be used in cryogenic temperatures?
  • A: Yes, like most austenitic grades, 347H remains ductile at very low temperatures, though it is primarily selected for its high-heat performance.
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Jiangyin Gaoxin Pipe Fittings Co., Ltd.
About Us
JIANGYIN GAOXIN PIPE FITTINGS CO.,LTD.
Our company is a professional manufacturer of pressure piping components. As Intergranular Corrosion Resistance Stainless Steel 347H Slip On Flanges Manufacturers，Our product range covers butt-weld, socket-weld, and threaded pipe fittings, including flanges and customized non-standard parts. These products are widely used in industries such as oil & gas, chemical processing, power generation, shipbuilding, papermaking, metallurgy, pharmaceuticals, and food processing. We manufacture according to standards such as ASME, EN,JIS,DIN,ANSI,GOST, MSS, GB/T,HG, DL, SH, SY,and have a complete range of inspection equipment, a strict quality control system, and various certifications（PED,AD2000,EAC, ABS,BV, DNV,NORSOK M650, ISO9001,ISO14001,ISO45001,etc.）, making us a leader in the industry.

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