Globe Valve Materials

Figure 1: Stainless steel globe valve for steam

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Selecting the correct globe valve material plays a crucial role in their performance and suitability for specific applications. By understanding the properties and benefits of different materials, one can select globe valves that not only meet the operational requirements of their systems but also offer longevity and reliability. Globe valves offer a range of material combinations tailored to meet specific requirements, like cost-effectiveness, corrosion resistance, or sustained performance under high-pressure conditions.

Table of contents

• Globe valve body materials
• Stem, seat, and disc materials
• Wear and erosion
• Sealing and leakage
• Globe valve material specifications and standards
• Design considerations

Globe valve body materials

The valve body, the primary structure of the globe valve, is subjected to the internal pressures of the system and must be robust enough to withstand the operating environment. Materials for the valve body are selected based on factors such as strength, corrosion resistance, and cost:

• Carbon steel: A popular choice for industrial applications due to its ruggedness and cost-effectiveness. Carbon steel offers a good balance between durability and price, making it suitable for a wide range of globe valve applications where extreme corrosion resistance is not a primary concern. The material is suitable for moderate to high temperatures and pressures, typically up to 800°F (427°C) and psi (136 bar), depending on the specific grade.
• Cast iron: Utilized in less demanding applications, cast iron provides adequate strength for lower pressure and temperature conditions. Its lower cost makes it an attractive option for systems where cost is a significant factor. Cast iron is generally suitable for temperatures up to 450°F (232°C) and pressures up to 250 psi (17.2 bar).
• Stainless steel: Chosen for environments where corrosion resistance is paramount. Stainless steel is ideal for applications involving aggressive media or in industries such as food processing and pharmaceuticals, where cleanliness and non-reactivity are crucial. Stainless steel can handle temperatures up to °F (538°C) and pressures up to psi (207 bar), depending on the alloy.
• PVC: PVC globe valves offer excellent corrosion resistance, are lightweight and cost-effective for handling corrosive materials. However, they are not suitable for high-temperature or high-pressure applications. Also, they have lower mechanical strength and thermal stability compared to metals. PVC is suitable for temperatures up to 140°F (60°C) and pressures up to 232 psi (16 bar).
• Forged steel: Forged steel globe valves are ideal for high-pressure and high-temperature applications due to their superior strength and durability. The forging process results in a denser, more uniform material structure, offering enhanced mechanical properties and resistance to impact and thermal fatigue. Forged steel is capable of withstanding temperatures up to °F (566°C) and pressures exceeding psi (414 bar), depending on the grade.

Read our chemical resistance guide for more information on the compatibility of materials with various media.

Stem, seat, and disc materials

The stem and disc are critical moving parts of a globe valve, responsible for the actual control of fluid flow. Material selection for these components is essential for ensuring the valve's functional integrity and longevity.

• Stem materials: Typically made from stainless steel, the stem must resist corrosion and wear, especially since it is in constant motion against the packing material to prevent leaks. Stainless steel's resistance to galling and seizure under these conditions makes it an ideal choice.
• Seat materials: The seat and disc come into direct contact with the fluid and must be made from materials that can withstand the fluid's properties, including corrosiveness and abrasiveness.
  • PTFE (Teflon): Excellent chemical resistance, low friction, good for non-abrasive fluids.
  • RTFE (Reinforced PTFE): Improves wear resistance compared to virgin PTFE for slightly abrasive fluids.
  • Metal: Various grades of stainless steel or bronze offer good wear resistance and high-temperature capabilities for harsher globe valve applications.
• Disc materials: Globe valves offer various disc designs:
  • Plug type disc: Offers maximum erosion resistance with its long and tapered design, making it suitable for applications where erosion is a concern. Stainless steel is widely used for plug type discs, offering excellent erosion resistance due to its durability and corrosion resistance.
  • Composition disc: Features a flat seat for moderate throttling but is not recommended for high-pressure applications due to its non-aerodynamic surface. Brass or bronze provides a good balance between cost and performance for composition discs.
  • Ball (conventional) disc: Provides a thin contact area that allows for good seating and moderate throttling. Ceramics are often used to make ball discs.

Typically, in cast iron globe valves, the disc and seat ring are often made of bronze, while in more demanding applications involving carbon steel or stainless steel valve bodies, the trim material is usually stainless steel. Read our chemical resistance guide for more details on the compatibility of various materials with different media.

Figure 2: Globe valve disc types: Plug disc (left), composition disc (middle), and ball disc (right)

Wear and erosion

• Hardfacing materials: In applications where globe valves are exposed to high velocity or abrasive media, hardfacing materials like Stellite are applied to disc and seat surfaces. This significantly enhances wear resistance, extending the valve's service life in demanding conditions.
• Erosion resistance: Erosion resistance is critical for globe valves in steam service, where the velocity of steam can cause rapid material degradation. Selecting materials with high erosion resistance like hardened stainless steel, stellite and nickel alloys ensures the valve's durability and operational efficiency.

Sealing and leakage

• Soft seating materials: For applications requiring tight shut-off, globe valves use soft seating materials such as PTFE. These materials offer superior sealing capabilities at lower temperatures, making them ideal for precise flow control applications where leakage must be minimized.
• Emission standards: Material selection in globe valves also addresses environmental concerns, particularly in minimizing fugitive emissions. Compliance with standards like ISO or API 622 is essential, with certain materials offering reduced leakage rates and improved environmental performance.

Globe valve material specifications and standards

• ASTM and ASME standards: Materials used in globe valve construction are subject to rigorous standards to ensure they meet the required mechanical and chemical properties for safe and efficient operation. ASTM International provides specifications for material composition and properties, while ASME standards, particularly ASME B16.34, detail the application of these materials in valve design, including pressure and temperature ratings. Adherence to these standards guarantees that globe valves can withstand the demands of their intended applications.
• NACE MR/ISO compliance: For globe valves used in oil and gas applications, especially where sour service conditions are present, materials must comply with NACE MR/ISO . This standard addresses the selection of materials resistant to sulfide stress cracking in corrosive environments, ensuring the longevity and reliability of valves in harsh conditions.
• Lead free globe valves: Essential for adhering to health and environmental safety standards in potable water systems, lead-free globe valves are made from materials that meet strict lead content regulations. The American National Standards Institute (ANSI) and the National Sanitation Foundation (NSF), particularly through the NSF/ANSI 61 and NSF/ANSI 372 standards, set the criteria for lead-free water system components.

Design considerations

Globe valves can feature a single-seat design with a disc that moves in and out of the flow path or a double-seated design that reduces the hydraulic load on each disc, beneficial for larger valves or those under high pressure. Additionally, the choice between a conventional design, where the process media directly contacts the disc, and a cage-guided design, which isolates the disc from pressure and deflection, depends on the application's specific requirements. However, cage-guided designs are not suitable for viscous media due to the risk of clogging. Cage-guided designs demand materials that can endure rapid flow dynamics and turbulence without degrading, like stainless steel or Hastelloy.

The Ultimate Guide to Forged Globe Valves: Strength, Precision, and Reliability

In the critical world of fluid control, where pressure, temperature, and reliability are paramount, Forged Globe Valves stand out as the preferred choice for severe service conditions. Unlike their cast counterparts, these valves are meticulously crafted from solid metal billets subjected to intense heat and pressure (forging), resulting in a denser, stronger, and more reliable microstructure. This guide dives deep into forged steel globe valves and forged stainless steel globe valves, exploring their construction, function, standards, materials, and key specifications.

What is a Forged Globe Valve

A Forged Globe Valve is a type of linear motion valve primarily designed for throttling flow and providing positive shut-off in high-pressure and high-temperature piping systems. The defining characteristic is its manufacturing process: key components like the valve body and bonnet are formed through forging. This process aligns the grain flow of the metal, significantly enhancing its mechanical strength, impact resistance, and integrity compared to casting. Forged globe valves are synonymous with durability and leak prevention in critical applications across oil & gas, power generation, chemical processing, and refining.

Anatomy of Strength: Forged Globe Valve Structure

Understanding the robust structure is key to appreciating their performance: 

1.  Forged Body:

The core pressure-containing component, shaped by forging for superior density and strength. Features inlet and outlet ports and the internal flow path.

2.  Forged Bonnet:

The forged cover bolted or threaded to the body, providing access to the internals and sealing the system pressure. Bonnet gaskets ensure a tight seal.

3.  Disc (Plug):

The movable element that modulates or stops flow by seating against or lifting from the stationary seat ring. Often tapered or parabolic for precise throttling.

4.  Seat Ring:

A hardened ring (often replaceable) installed in the body against which the disc seals to achieve shut-off.

5.  Stem:

A precision-machined shaft that transmits the force from the actuator (handwheel, gear, etc.) to the disc. Connected via threads (rising stem design is common).

6.  Yoke & Actuator Mounting:

The structure connecting the bonnet to the actuator (handwheel, gear operator, pneumatic/hydraulic actuator).

7.  Packing Gland:

The assembly compressing packing material around the stem to prevent leakage along the stem path while allowing movement.

Core Function: Precision Flow Control and Shut-off

The primary functions of a forged globe valve are: 

1.  Throttling Control:

The design allows for precise modulation of flow rate. The disc’s linear movement relative to the seat enables fine adjustments, making it excellent for regulating flow.

2.  Positive Shut-off:

When fully closed, the disc seats firmly against the seat ring, creating a bubble-tight seal capable of handling high pressures. This is critical for isolation and safety.

3.  Flow Direction:

Globe valves have a distinct flow direction (indicated by an arrow on the body). Flow typically enters below the seat and exits above it, ensuring proper sealing and seat loading when closed. Reversing flow can cause premature wear or leakage.

Standards Governing Forged Globe Valves (API 602)

Quality and interchangeability are ensured by stringent standards. The most prominent is: 

*   API 602:

This American Petroleum Institute standard, titled “Compact Design Gate, Globe, and Check Valves for Refinery Use,” is the definitive specification for **forged steel globe valves**, gate valves, and check valves 2 inches (DN 50) and smaller. It covers design, materials, testing, inspection, and pressure-temperature ratings for **API 602 Forge Globe Valves**. Compliance with API 602 signifies high integrity for critical hydrocarbon service.

*   ASME B16.34:

This standard defines pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing requirements for valves of all sizes, including larger forged globe valves. It establishes the foundation for pressure classes (e.g., Class 800).

*   Other Standards:

MSS SP-42 (Corrosion Resistant Valves), MSS SP-80 (Bronze Gate, Globe, Angle & Check Valves – though primarily bronze), BS (UK equivalent to API 602), and various ISO standards may also apply depending on region and application.

Material Matters: Construction of Forged Globe Valves

The forging process utilizes high-quality materials suitable for demanding environments: 

*   Carbon Steel (ASTM A105):

The most common material for general high-pressure/temperature service. Offers excellent strength and value. A105 forged steel globe valves are widely used in steam, oil, and gas.

*   Low-Temp Carbon Steel (ASTM A350 LF2/LF3):

Used for sub-zero temperature applications to prevent brittle fracture.

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*   Alloy Steels (ASTM A182 F11, F22, F91):

Provide enhanced strength and corrosion resistance at elevated temperatures (e.g., power plants).

*  Stainless Steels (ASTM A182 F304/F304L, F316/F316L, F347):

Essential for corrosion resistance in chemical, petrochemical, marine, and food-grade applications. Forged stainless steel globe valves offer durability against a wide range of aggressive media.

*   Duplex/Super Duplex Stainless Steels (ASTM A182 F51, F53, F55):

For exceptional strength and corrosion resistance in highly corrosive environments (e.g., offshore, chlorides).

*   Nickel Alloys (Alloy 400, 600, 625, C276):

For the most severe corrosive and high-temperature services.

Handling the Pressure: Pressure Range and Class Ratings

Forged globe valves are specifically engineered for high-pressure service: 

*   Pressure Class:

Primarily conform to ASME B16.34 pressure classes. Common classes include 800, , and .

*   Class 800 Dominance:

Forged steel globe valve class 800 is arguably the most prevalent standard rating for high-pressure applications in the 2″ and smaller sizes governed by API 602. It signifies suitability for pressures up to psig (95 bar) at 100°F (38°C), with ratings decreasing as temperature increases (per ASME B16.34 tables).

*   Higher Classes:

Class ( psig @ 100°F) and Class ( psig @ 100°F) are used for even more extreme pressures. **Forged globe valves** excel in these ranges due to their inherent strength.

*   Example:

A 1 2 800 forged steel threaded globe valve refers to a 1/2 inch size, Class 800 pressure rating, carbon steel (typically A105) valve with threaded ends.

Ensuring Fit: Dimensions of Forged Globe Valves

Dimensions are standardized for interchangeability: 

*   API 602 Compact Design:

Valves built to API 602 have specific face-to-face dimensions, significantly shorter than standard ASME B16.10 dimensions for equivalent cast valves. This “compact” design saves space and weight.

*   End Connections:

Common options include:

    *   Threaded (NPT, BSPT, BSPP) – Common for smaller sizes like the 1 2 800 forged steel threaded globe valve.

    *   Socket Weld (SW) – Popular for high-integrity small bore piping.

    *   Butt Weld (BW) – Used for the highest integrity, permanent installations. Requires beveled ends per ASME B16.25.

    *   Flanged (Less common for small forged valves; ASME B16.5 dimensions apply).

*   Key Dimensions:

Face-to-face (F2F), end-to-end (for flanged), center-to-face (for angle pattern valves), stem rise (for rising stem), handwheel diameter, and bolt circle/bore for flanged bonnets. Always refer to manufacturer’s dimensional drawings for specific models.

Finding Quality: Forged Globe Valve Manufacturers and Suppliers

Choosing a reliable source is critical for performance and safety

*   Reputable Forged Globe Valve Manufacturers:

Look for established manufacturers with:

    *   API 602 Monogram License (crucial for oil & gas).

    *   ISO Quality Management certification.

    *   Extensive material traceability and testing (e.g., PMI, NDE, hydrostatic testing).

    *   Proven experience in your industry.

*   Trusted Forged Globe Valve Suppliers:

Distributors and forged globe valve suppliers play a vital role. Select partners who:

    *   Source from reputable, certified forged globe valve manufacturers.

    *   Offer technical expertise and application support.

    *   Maintain comprehensive inventory for common sizes/materials (e.g., A105 forged steel globe valve, forged stainless steel globe valves).

    *   Provide reliable logistics and after-sales support.

    *   Can source specialized valves (e.g., forged steel globe valve class 800 in exotic materials).

If you want to learn more, please visit our website Cast Iron Globe Valve-DIN.

Conclusion: The Indispensable Forged Solution

Post time: May-30-