ASME SB338 GR7 Titanium Alloy Steel Heat Exchanger Tube , Power Plant

ASME SB338 Grade 7 refers to a specific standard and material specification for Titanium Alloy (Ti-0.2Pd). The material is primarily used in applications requiring both high corrosion resistance and high strength under various challenging conditions.

ASME SB338 Gr. 7 designates a titanium alloy containing Titanium (Ti) as the base metal and 0.12% to 0.25% Palladium (Pd) as the alloying element. The addition of palladium to titanium gives the alloy superior corrosion resistance, particularly against acidic environments and seawater.

The excellent corrosion resistance results in reduced maintenance and longer service life compared to other materials like stainless steel or carbon steel.

Chemical Composition:

• Titanium Grade 7 (Ti-0.2Pd) is an alloy primarily composed of titanium with a small percentage of palladium (0.12-0.25%). This alloy is designed to offer enhanced corrosion resistance, especially in aggressive environments such as in seawater, chemicals, or heat exchangers.
• Titanium (Ti) is known for its excellent strength-to-weight ratio, outstanding corrosion resistance, and ability to perform under high temperatures.
• Palladium (Pd) is added to Grade 7 to improve resistance to general corrosion, particularly in acidic environments.

Mechanical Properties:

• Tensile Strength: Titanium Grade 7 has a high tensile strength, typically ranging between 550 to 750 MPa (80-110 ksi).
• Yield Strength: The yield strength is typically around 275 to 450 MPa (40-65 ksi), which ensures the material performs well under pressure without permanent deformation.
• Elongation: The elongation in the tensile test for Grade 7 titanium alloy tubes is typically around 15-20%, indicating good ductility.

Applications:

1. Heat Exchangers: Primarily used in heat exchangers, especially in environments with high corrosion potential such as desalination plants, chemical processing industries, and offshore oil and gas platforms.
2. Marine and Offshore Applications: Its superior corrosion resistance makes it suitable for marine applications where the heat exchanger tubes are exposed to saltwater.
3. Petrochemical and Chemical Industries: The alloy’s ability to withstand acidic and corrosive environments makes it ideal for heat exchangers used in chemical processing industries.

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