Gr5 Gr7 Class 150 ASME B16.5 Titanium Flanges Slip On Flange Raised Face SORF for Piping Systems

Gr5 Gr7 Class 150 ASME B16.5 Titanium Flanges Slip On Flange Raised Face SORF for Piping Systems

Abstract:

Titanium alloys, particularly Gr5 and Gr7, are increasingly being used for flange manufacturing in industrial applications due to their exceptional corrosion resistance, high strength-to-weight ratio, and suitability for extreme environments. ASME B16.5 is a widely recognized standard that governs the design, dimensions, material specifications, and pressure ratings for flanges used in industrial piping systems. This paper focuses on the design and application of Gr5 and Gr7 titanium flanges according to the ASME B16.5 standard, with a particular emphasis on Class 150, Flat Flange, Slip-On Flange, Raised Face (SORF), and Slip-On Flat Face (SOFF) designs. The paper examines the material properties, advantages, and the manufacturing processes of these titanium flanges, highlighting their industrial applications in areas such as chemical processing, aerospace, marine engineering, and power generation.

1. Introduction

Flanges are crucial components in industrial piping systems, acting as the interface between pipes, valves, and other equipment. The ASME B16.5 standard provides the specifications for flanges used in piping systems, ensuring compatibility and safety in operation. Among the various materials used for flange construction, titanium alloys have gained significant attention due to their high strength, low weight, and exceptional corrosion resistance. Gr5 (Ti-6Al-4V) and Gr7 (Ti-0.15Pd) titanium alloys are particularly suited for flange manufacturing in applications that require both structural integrity and resistance to harsh environments.

This paper aims to explore the design, manufacturing processes, and applications of ASME B16.5 Gr5 and Gr7 titanium flanges, specifically focusing on Class 150, Flat Flanges, Slip-On Flanges, Raised Face (SORF), and Slip-On Flat Face (SOFF) types. The paper will also examine the advantages of using titanium alloys over other materials in industrial settings.

2. Overview of ASME B16.5 Standard:

The ASME B16.5 standard specifies the requirements for flanges, including their dimensions, materials, and pressure ratings. It is essential for ensuring the uniformity and integrity of flange connections in a wide range of industrial applications. Some of the key aspects covered by the ASME B16.5 standard include:

• Flange Types: The standard covers a variety of flange types, including Weld Neck, Blind, Slip-On, and Flat Flanges. Each type serves a different function based on the application requirements.
• Pressure Ratings: The standard classifies flanges by their pressure ratings, ranging from Class 150 to Class 2500. Class 150 flanges, in particular, are widely used in medium-pressure applications.
• Material Specifications: The material of the flange is critical in determining its performance under different operating conditions. Titanium alloys like Gr5 and Gr7 are included in the standard due to their superior properties.

3. Material Properties of Gr5 and Gr7 Titanium Alloys:

3.1 Gr5 Titanium Alloy (Ti-6Al-4V)
Gr5 titanium alloy, also known as Ti-6Al-4V, is the most commonly used titanium alloy and consists of 90% titanium, 6% aluminum, and 4% vanadium. This alloy offers a combination of high strength, low weight, excellent corrosion resistance, and good weldability. The properties of Gr5 titanium alloy include:

• Tensile Strength: 900-1,100 MPa
• Yield Strength: 850-1,000 MPa
• Corrosion Resistance: Excellent resistance to saltwater, acids, and chlorides, making it ideal for marine and chemical processing applications.
• Applications: Aerospace, medical implants, and industrial piping systems requiring high strength and lightweight materials.

3.2 Gr7 Titanium Alloy (Ti-0.15Pd)
Gr7 titanium alloy, also known as Ti-0.15Pd, is a variant of commercially pure titanium with a small addition of palladium (0.15%). This addition enhances its resistance to corrosion, especially in aggressive environments such as high-purity acids and seawater. The properties of Gr7 titanium alloy include:

• Tensile Strength: 550-700 MPa
• Yield Strength: 450-650 MPa
• Corrosion Resistance: Excellent resistance to a wide range of corrosive environments, particularly in the chemical and marine industries.
• Applications: Chemical processing, marine engineering, and other applications where superior corrosion resistance is required.

4. Design of ASME B16.5 Titanium Flanges:

The design of titanium flanges follows the ASME B16.5 standard, with specific considerations given to the material's properties and the intended application. Titanium flanges are designed to handle specific pressure ratings, with Class 150 being one of the most common ratings used for medium-pressure systems.

4.1 Class 150 Flanges
Class 150 titanium flanges are suitable for medium-pressure applications where the operating pressure does not exceed 150 pounds per square inch (psi) at ambient temperature. They are commonly used in piping systems in industries such as chemical processing, power generation, and water treatment.

4.2 Flange Types

• Flat Flanges: Flat flanges have a flat face with no raised area. They are often used for low-pressure applications and are easier to manufacture.
• Slip-On Flanges: These flanges are designed to slide over the pipe and are welded into place. Slip-on flanges are commonly used for applications where welding accessibility is important.
• Raised Face (SORF): Raised face flanges have a small raised area around the flange's bore to create a tighter seal when bolted to the mating flange. SORF flanges are widely used in higher-pressure systems and are known for providing a more reliable seal.
• Slip-On Flat Face (SOFF): These flanges combine the features of slip-on and flat face designs. They are often used in systems where the flanges are exposed to low pressure and require easy assembly and disassembly.

5. Manufacturing of Titanium Flanges: 

Manufacturing titanium flanges involves several key processes to ensure that the final product meets the ASME B16.5 standard's dimensional and material specifications.

5.1 Material Selection
Selecting the appropriate grade of titanium alloy (Gr5 or Gr7) is crucial for the flange's performance. Titanium alloys are chosen based on the expected operating conditions, including pressure, temperature, and corrosion potential.

5.2 Machining and Forming
Titanium flanges are produced through processes such as forging, machining, and welding. Forging is commonly used to shape the flanges, while machining is used to achieve the required dimensions and surface finishes.

5.3 Welding
When welding titanium flanges, special care must be taken to avoid contamination, as titanium is highly reactive with oxygen. Shielded gas welding techniques, such as tungsten inert gas (TIG) welding, are commonly used for titanium flanges.

5.4 Surface Treatment
Titanium flanges may undergo surface treatments such as anodizing or passivation to enhance their corrosion resistance and improve their overall performance in harsh environments.

6. Applications of Titanium Flanges in Industry:

Titanium flanges, especially Gr5 and Gr7, are used in various industrial applications due to their excellent properties. Some key applications include:

• Chemical Processing: Titanium's corrosion resistance makes it ideal for handling aggressive chemicals in processes such as distillation, filtration, and mixing.
• Marine Engineering: Titanium's ability to resist corrosion in seawater makes it an ideal material for flanges used in marine piping systems.
• Aerospace: Gr5 titanium is commonly used in aerospace applications due to its strength, lightweight, and durability under extreme conditions.
• Power Generation: Titanium flanges are used in steam and gas turbines, as well as heat exchangers, where high strength and resistance to heat and corrosion are crucial.

7. Conclusion:

ASME B16.5 Gr5 and Gr7 titanium flanges are essential components in many industrial piping systems. Their superior material properties, including high strength, lightweight, and excellent corrosion resistance, make them ideal for applications in harsh environments such as chemical processing, marine engineering, and aerospace. The careful selection of flange type, material, and design according to the ASME B16.5 standard ensures the reliability and performance of these flanges in industrial applications. As industries continue to demand higher performance from their materials, titanium alloys like Gr5 and Gr7 will play an increasingly important role in flange manufacturing.