Valve Materials Guide: Material Types, Performance & Selection

When selecting valves, many people focus first on valve types such as ball valves, gate valves, and butterfly valves, while overlooking the importance of material selection.
Based on Plumberstar‘s engineering experience, the valve type determines its function, while the material determines whether it can operate reliably over the long term under actual working conditions. Even for the same valve, the required material may vary completely depending on whether it is used for clean water, steam, seawater, or chemical media.

This guide focuses on valve body materials and sealing materials, while also considering the material requirements of internal components. It explains the performance characteristics, typical applications, and selection principles of common valve materials.

1. Why Valve Material Selection Matters

Many projects pay more attention to valve type, pressure rating, or purchase price during selection, while overlooking the material itself. In reality, the material directly affects valve service life, operational reliability, maintenance costs, and project acceptance.

1) Corrosion Resistance Determines Valve Service Life

Corrosion is one of the most common causes of valve failure, and different media attack materials in completely different ways. Seawater, chlorinated circulating water, acidic and alkaline media, and clean water all impose different corrosion resistance requirements. If the material is incompatible with the medium, the valve may suffer leakage, strength degradation, or premature failure due to corrosion, even if its manufacturing quality is not an issue.
Therefore, the first step in engineering material selection is to identify the process medium and then select a material with suitable corrosion resistance.

Valve Failure Caused by Corrosion

2) Pressure and Temperature Determine Operational Reliability

Every material has its own pressure and temperature limits. When a system operates continuously under high temperature, high pressure, or frequent pressure fluctuations, the material’s strength, dimensional stability, and sealing performance are all affected. Even if the valve performs normally for a short period, long-term operation may significantly reduce its service life.
Therefore, material selection should be based on continuous operating conditions rather than only the maximum temperature or pressure rating.

Different Types of Pressure Valves

3) Mechanical Properties Affect System Stability

In industrial piping systems, valves are subjected not only to internal pressure but also to external loads such as water hammer, vibration, frequent cycling, and pipeline stress. If the material lacks sufficient strength, toughness, or fatigue resistance, problems such as body cracking, stem deformation, or seal failure may occur even without corrosion.
For high-cycle, large-diameter, or high-pressure systems, mechanical properties are often just as important as corrosion resistance.

4) Material Selection Affects Total Life-Cycle Cost

Many buyers focus first on purchase price. However, for engineering projects, the purchase cost of a valve is only a small part of its total life-cycle cost. Maintenance, replacement, downtime, and labor costs caused by improper material selection are often far greater than the difference in material cost.
Therefore, material selection affects not only the valve itself, but also the reliability and total life-cycle cost of the entire piping system.

5) Material Selection Affects Project Compliance and Acceptance

In addition to performance requirements, many industries also have specific regulations and certification requirements for valve materials. For example, drinking water, food processing, pharmaceuticals, gas distribution, and chemical industries may all require approved materials and sealing components that comply with applicable standards.
If the selected materials do not meet project specifications, the valve may fail final acceptance even if it performs properly.

Required Certifications and Compliance Documents

2. Understanding Valve Material Categories

When selecting valve materials, many people simply compare brass, stainless steel, and carbon steel. In reality, this comparison is incomplete because a valve is not made from a single material. It consists of multiple components, each serving a different function and requiring different material properties.

Therefore, engineering material selection mainly involves Body Materials and Seal Materials. Internal components such as stems, balls, and discs are typically selected according to specific operating conditions to meet requirements for wear resistance, corrosion resistance, and sealing performance.

Valve Body and Seal Cross-Section

1) Body Materials

The valve body is the main structural component of a valve. It withstands system pressure and external loads, making it the material that buyers are usually most concerned about. The most common valve body materials for industrial and commercial valves include:

• Brass
• Bronze
• Cast Iron
• Ductile Iron
• Carbon Steel
• Stainless Steel
• Zinc Alloy
• Aluminum Alloy
• Engineering plastics such as PVC, CPVC, and UPVC

2) Seal Materials

Compared with valve body materials, sealing materials are often overlooked. In practice, however, they play a critical role in leakage performance and maintenance intervals.
Common valve sealing materials include:

• PTFE (Polytetrafluoroethylene)
• EPDM (Ethylene Propylene Diene Monomer)
• NBR (Nitrile Butadiene Rubber)
• FKM (Fluoroelastomer / Viton®)
• Graphite

Although sealing materials account for only a small portion of the total valve cost, they have a significant impact on leakage rates, maintenance intervals, and service life.

3. Common Valve Body Materials

The valve body is the main structural component of a valve. It withstands system pressure, connects to the pipeline, and protects internal components. As the most expensive part of the valve, it is also the primary focus of material selection. The following are the most common valve body materials used in engineering projects.

1) Brass

Brass offers an excellent balance of corrosion resistance, machinability, and cost, making it a cost-effective choice for low- and medium-pressure fluid systems.

Brass Valve

Typical Applications

• Hot and cold water systems
• HVAC systems
• Gas distribution
• Residential water supply
• Underfloor heating manifolds
• Low- and medium-pressure compressed air systems

Advantages
Brass has excellent forging and machining properties, making it easy to produce precision threads and reliable sealing surfaces. It also provides good corrosion resistance in potable water systems. For small-diameter valves (DN15–DN50), brass remains one of the most widely used materials due to its balance of performance and cost.

Limitations
Brass is not suitable for long-term service in high-temperature, high-salinity, or seawater environments. Continuous operating temperatures are generally limited to 120°C (up to 150°C for short-term exposure). In high-chloride environments, brass is susceptible to dezincification, which reduces material strength and increases the risk of leakage.

2) Bronze

Although bronze looks similar to brass, it generally provides better corrosion resistance, especially in seawater, salt spray, and high-humidity environments.

Bronze Valve

Typical Applications

• Marine engineering
• Shipbuilding systems
• Seawater cooling systems
• Fire protection systems
• Industrial HVAC systems
• Industrial water supply systems

Advantages
Bronze is more stable than standard brass in saline and marine environments. It also offers better resistance to dezincification and wear. As a result, bronze remains a common valve body material for marine, seawater, and certain fire protection applications.

Limitations
Bronze is more expensive than brass and generally has lower pressure capability than carbon steel and stainless steel. It is therefore not a general-purpose material for medium- and high-pressure industrial piping. For residential water supply systems, bronze usually offers little economic advantage.

3) Stainless Steel

Stainless steel is one of the most commonly used corrosion-resistant materials for industrial valves. The most common grades are 304, 316, and 316L.

Stainless Steel Valve

Typical Applications

• Chemical processing
• Oil and gas
• Food processing
• Pharmaceutical industry
• Marine engineering
• High-purity fluid handling

Advantages
Stainless steel combines excellent corrosion resistance, mechanical strength, and temperature resistance. 304 is suitable for general industrial media. 316 contains molybdenum, providing better resistance to chloride corrosion, making it more suitable for marine, chemical, and coastal environments. 316L has a lower carbon content and better weldability, making it widely used in food processing, pharmaceutical manufacturing, and hygienic piping systems.

Limitations
Stainless steel is more expensive and more difficult to machine than brass or carbon steel, making it unnecessary for many commercial applications. Under highly concentrated acids, alkalis, or corrosive media, standard 304 or 316 stainless steel may still fail, requiring further evaluation of specialized materials.

4) Carbon Steel

Carbon steel offers lower corrosion resistance than stainless steel, but its high strength and pressure capacity make it a common choice for high-temperature and high-pressure industrial systems.

Carbon Steel Valve

Typical Applications

• Oil and gas
• Steam systems
• Power plants
• Petrochemical industry
• High-pressure industrial pipelines

Advantages
Carbon steel provides high strength and excellent impact resistance, making it suitable for steam, hot oil, and industrial main pipelines. Compared with brass and cast iron, it performs better in high-temperature, high-pressure, and heavy-duty industrial applications.

Limitations
Carbon steel is susceptible to corrosion and is not suitable for corrosive media or continuously wet environments without protective coatings or other anti-corrosion treatments. It also has limited low-temperature performance. Standard carbon steel is generally not recommended for service below −20°C due to the risk of brittle fracture.

5) Cast Iron

Cast iron is economical and easy to cast, making it widely used in large-diameter, low-pressure piping systems.

Cast Iron Valve

Typical Applications

• Municipal water supply
• Fire protection networks
• Wastewater treatment
• Cooling water systems
• Large-diameter, low-pressure pipelines

Advantages
Cast iron is well suited for manufacturing large valve bodies and provides excellent cost performance in clean water, air, and other non-corrosive media under low- and medium-pressure conditions. As a result, many large butterfly valves and gate valves still use cast iron bodies.

Limitations
Cast iron has relatively low toughness and is less resistant to impact and water hammer than ductile iron. In humid or corrosive environments, epoxy coatings or other protective treatments are generally required.

6) Ductile Iron

Ductile iron offers significantly higher strength and toughness than cast iron and is widely used for large-diameter water supply valves.

Ductile Iron Value

Typical Applications

• Municipal water supply
• Underground pipeline networks
• Water treatment plants
• Large butterfly valves
• Large gate valves
• Fire protection systems

Advantages
Ductile iron provides a good balance of strength, toughness, and cost. Compared with gray cast iron, it withstands water hammer, pressure fluctuations, and external impact much better. It is commonly used for DN100 and larger butterfly valves, gate valves, and fire protection systems.

Limitations
Ductile iron still requires corrosion protection and does not provide the same corrosion resistance as stainless steel. For seawater, chemical media, or hygienic applications in the food and pharmaceutical industries, stainless steel, bronze, or other suitable materials are generally recommended.

7) PVC

PVC valves are widely used in low-pressure, ambient-temperature, and corrosive applications, particularly in water treatment, irrigation, and light chemical piping systems.

PVC Value

Typical Applications

• Chemical dosing systems
• Water treatment
• Agricultural irrigation
• Swimming pool circulation systems
• Acid and alkali transfer

Advantages
PVC offers excellent chemical resistance and remains stable in many acidic, alkaline, and saline media without the risk of rust. It is also lightweight, easy to install, and requires no additional corrosion protection, making it an ideal choice for small and medium-sized low-pressure systems.

Limitations
PVC is primarily limited by temperature, pressure, and mechanical strength. It is generally suitable for low-pressure applications between 0°C and 60°C. It is not recommended for high-temperature, high-pressure, steam, or other critical industrial services. Outdoor installations should also consider UV aging and impact resistance.

8) Zinc Alloy & Aluminum Alloy

Zinc alloy and aluminum alloy are used in selected valve products where lightweight construction or low manufacturing cost is the primary requirement. Compared with brass, stainless steel, and carbon steel, they are less commonly used for pressure-bearing valve bodies.

zinc alloy valve

Zinc Alloy Applications

• Mini ball valves
• Angle valves
• Bibcocks
• Economy plumbing valves

Aluminum Alloy Applications

• Pneumatic valves
• Valve actuator housings
• Compressed air equipment
• Lightweight valve components

Advantages
Zinc alloy offers excellent die-casting performance and low production cost, making it suitable for high-volume manufacturing of economical valves. Aluminum alloy is lightweight, easy to machine, and provides good corrosion resistance in dry environments.

Limitations
Neither material is recommended for high-pressure, high-temperature, steam, seawater, or highly corrosive applications. For pressure-bearing valve bodies, brass, stainless steel, carbon steel, and ductile iron generally provide better strength, durability, and long-term reliability.

4. Valve Seat and Seal Materials

The valve body determines whether a valve can withstand operating conditions, while the sealing material determines whether it can maintain a reliable seal over the long term. In many cases, valve leakage is not caused by body failure, but by incompatibility between the seat, O-rings, packing, and the operating medium or temperature. Therefore, sealing materials should always be selected together with the valve body material.

Seal Materials

1) PTFE (Polytetrafluoroethylene)

PTFE is one of the most widely used valve seat sealing materials and is commonly found in ball valves, butterfly valves, and some globe valves.
Suitable Media

• Water
• Natural gas
• Air
• Most acids and alkalis
• Chemical fluids

Advantages
Excellent chemical stability, outstanding resistance to most chemicals, low coefficient of friction, low operating torque, and reliable sealing performance.

Limitations
Continuous operating temperature is generally limited to 180°C. Under high-temperature, high-pressure, or frequent cycling conditions, PTFE is prone to cold flow and wear, making it unsuitable for long-term steam service.

2) EPDM (Ethylene Propylene Diene Monomer)

EPDM is the most commonly used rubber sealing material for water supply and HVAC systems.
Suitable Media

• Hot and cold water
• Drinking water
• HVAC systems
• Cooling water
• Mild acids and alkalis

Advantages
Excellent resistance to water, ozone, and weathering. It performs well under long-term heating and cooling cycles and is widely used in water supply and HVAC applications.

Limitations
EPDM is not compatible with mineral oils, fuels, or most petroleum-based media. Prolonged exposure to high temperatures accelerates aging, making it unsuitable for fuel systems and high-temperature applications.

3) NBR (Nitrile Butadiene Rubber)

NBR is the most commonly used oil-resistant rubber sealing material in industrial valves.
Suitable Media

• Hydraulic oil
• Diesel
• Lubricating oil
• Compressed air
• Certain gas systems

Advantages
Excellent oil resistance and wear resistance at a relatively low cost, making it widely used in hydraulic, pneumatic, and fuel systems.

Limitations
NBR has limited resistance to both high and low temperatures and is not suitable for strongly oxidizing chemicals or prolonged high-temperature service.

4) FKM (Viton)

FKM is a high-performance elastomer with excellent resistance to high temperatures and chemical corrosion.

Suitable Media

• High-temperature oils
• Fuels
• Chemical media
• Solvents
• Hot air

Advantages
Compared with NBR, FKM offers superior heat resistance and chemical resistance. It is therefore widely used in petrochemical processing, high-temperature fluids, and certain automotive applications.

Limitations
FKM is relatively expensive and usually provides little advantage for standard water supply systems.

5) Graphite

Flexible graphite is primarily used in high-temperature industrial valves.

Graphite Seal Ring

Suitable Media

• Steam
• Heat transfer oil
• High-temperature gases
• High-temperature industrial pipelines

Advantages
Graphite withstands much higher temperatures than rubber sealing materials (-200°C to 450°C) and is widely used in steam valves, globe valves, and high-temperature gate valves. It also provides excellent pressure resistance while maintaining reliable sealing performance under elevated temperatures.

Limitations
Graphite has limited elasticity and requires higher installation accuracy. It is generally unsuitable for low-pressure residential applications that require bubble-tight sealing.

5. How to Select Valve Materials by Operating Conditions

Valve material selection should begin with the operating conditions rather than comparing whether brass, stainless steel, or carbon steel is “better.” Once the medium, temperature, pressure, and installation environment are clearly defined, the range of suitable materials can usually be narrowed down quickly.

1) Select Materials by Medium

The process medium is the first consideration in material selection. The table below summarizes the recommended body and sealing materials for common applications to provide a quick reference.

2) Select Materials by Temperature

Temperature affects not only the valve body but also the sealing materials.

Low-Temperature Service (≤ -20°C)
Material toughness becomes critical at low temperatures to prevent brittle fracture. Standard carbon steel and gray cast iron are generally not recommended. 316L stainless steel or low-temperature carbon steel is preferred, while PTFE or low-temperature-grade FKM is recommended for sealing materials.

Normal Temperature (-20°C to 80°C)
This is the most common operating range for water supply, HVAC, and general industrial systems. Brass, ductile iron, and 304 stainless steel are typically suitable, while EPDM, PTFE, or NBR should be selected according to the process medium.

Medium-High Temperature (80°C to 180°C)
The valve body is usually not the limiting factor, but standard rubber seals begin to age more rapidly. Particular attention should be paid to whether the sealing material is suitable for continuous service.

High-Temperature Service (180°C to 450°C)
Carbon steel and stainless steel are typically used for the valve body. Flexible graphite, metal seats, or high-temperature FKM are preferred for sealing. PVC, standard rubber seals, and standard PTFE are generally not recommended.

Ultra-High Temperature (>450°C)
These applications normally require high-temperature alloy steel bodies combined with pure graphite or metal sealing systems. Conventional non-metallic soft seals are not suitable for this temperature range.

3) Select Materials by Pressure

Operating pressure directly determines the mechanical strength required for the valve body. As pressure increases, material strength, wall thickness, and manufacturing quality become more critical. Material selection should not be based solely on the process medium or purchase cost.

Low-Pressure Applications (Typically ≤1.6 MPa / PN16)
Brass, ductile iron, certain gray cast iron valves, and PVC valves are generally suitable. These materials are commonly used in residential water supply, irrigation, and general industrial water systems.

Medium-Pressure Applications (Approximately 1.6–6.4 MPa / PN16–PN64)
Carbon steel, stainless steel, and ductile iron are generally recommended. PVC is not suitable for this pressure range. Standard gray cast iron should also be used with caution, especially in systems subject to pressure fluctuations or water hammer.

High-Pressure Applications (Typically >6.4 MPa / Above PN64)
High-strength carbon steel, forged carbon steel, or stainless steel is typically required. These materials are commonly used in steam systems, oil and gas pipelines, and industrial transmission lines. Low-strength materials should not be used to avoid the risk of deformation, cracking, or pressure failure.

4) Select Materials by Installation Environment

The same process medium may require different materials under different installation environments. Indoor systems generally have a lower corrosion risk and can be selected according to the process medium, temperature, and pressure. Outdoor, coastal, and chemical plant installations require additional consideration of environmental corrosion.

Indoor Applications
No special corrosion protection is normally required. Materials can be selected according to the process medium, temperature, and pressure.

Outdoor Applications
Rain, UV exposure, temperature fluctuations, and long-term weathering should all be considered. Standard cast iron and unprotected brass are generally not recommended for prolonged outdoor exposure. Epoxy-coated ductile iron or stainless steel is preferred, while EPDM or FKM is recommended for weather-resistant sealing.

Marine and Coastal Environments
Salt spray and chloride corrosion are the primary concerns. 316L stainless steel, aluminum bronze, or bronze should be used for valve bodies. Standard brass, carbon steel, and cast iron are generally not recommended.

Chemical Plant Environments
In addition to process media, airborne corrosive gases should also be considered. Depending on the corrosion level, 304, 316, or higher-grade stainless steels may be required. PTFE and FKM are commonly used as corrosion-resistant sealing materials.

Food & Drinking Water Applications
Compliance takes priority over cost. Valve bodies are typically manufactured from food-grade 304/316 stainless steel or lead-free brass, while sealing materials should also comply with the applicable hygiene and potable water standards.

6. Valve Material Selection Quick Reference

In practice, engineers do not need to memorize every material property. The goal is to quickly identify which materials are suitable for a given application. The following two tables provide a practical reference for preliminary material selection.

1) Valve Body Material Comparison

The valve body is responsible for withstanding pressure, connecting the pipeline, and protecting internal components. Material selection should therefore focus on corrosion resistance, operating pressure, continuous operating temperature, and project budget.

The values above are typical engineering references. Actual material selection should also consider valve design, manufacturing standards, and the manufacturer’s technical specifications.

2) Valve Seal Material Comparison

The table below summarizes the corrosion resistance, pressure capability, continuous operating temperature, cost, and typical applications of common sealing materials.

Compared with the valve body, sealing components typically account for less than 10% of the total valve cost, yet they determine the long-term sealing performance of most valves. For this reason, we always evaluate the valve body material and sealing material together during project reviews rather than considering only the valve body.

7. Common Material Selection Mistakes

Based on Plumberstar’s engineering experience, most premature valve failures are not caused by manufacturing defects but by improper material selection. The following are some of the most common mistakes encountered in engineering projects.

1) Focusing Only on Purchase Price

Low-cost materials may perform adequately in clean water systems, but when used in corrosive, high-temperature, or high-pressure applications, they often fail prematurely due to leakage, corrosion, or material degradation. The cost of replacement and downtime is usually far greater than the initial savings.

Valve Failure Repair

Engineering Recommendation: Evaluate materials based on service life and maintenance costs rather than purchase price alone.

2) Focusing Only on the Valve Body

Many buyers verify whether the valve body is made of 304 or 316 stainless steel but overlook the valve seat, O-rings, and packing. For example, using EPDM in oil service or standard PTFE in high-temperature steam applications can result in seal failure while the valve body remains intact.

Seal Failure Repair

Engineering Recommendation: Always verify both the valve body material and the sealing material.

3) Specifying Only the Medium Name

“Water” may refer to tap water, groundwater, seawater, cooling water, or chlorinated circulating water. Likewise, “chemical media” may require completely different materials depending on concentration.

Valve Corroded by the Process Medium

Engineering Recommendation: Provide the medium composition, concentration, operating temperature, and corrosion level whenever possible.

4) Ignoring the Installation Environment

Even for water systems, indoor and coastal environments require different material selections. In salt-spray environments, standard brass, cast iron, and 304 stainless steel may corrode much faster, making 316L stainless steel, bronze, or aluminum bronze a better choice.

Valve Corrosion in Coastal Environments

Engineering Recommendation: Evaluate environmental corrosion separately for outdoor, coastal, and chemical plant installations.

5) Overlooking Certification Requirements

For drinking water, food, pharmaceutical, and gas applications, regulatory compliance is often more critical than material strength. Drinking water systems may require certifications such as NSF, WRAS, ACS, KTW, or DVGW, while food and pharmaceutical applications may require FDA or EC 1935/2004 compliance. Gas systems must also comply with applicable local standards. Even if the material performs well, the valve may still fail project acceptance without the required certifications.

Industry-Certified Valves

Engineering Recommendation: Confirm the required certifications before selecting the valve body, seals, and surface treatment.

8. Valve Material Selection Checklist

When receiving an inquiry, we always confirm the following information before recommending suitable materials.
If you are sourcing valves, you can also use the checklist below as a reference.

1) Basic Operating Conditions

• Identify the process medium, such as clean water, steam, oil, chemicals, seawater, or wastewater.
• Confirm whether the medium is corrosive and whether it contains chlorides, acids, alkalis, oils, or other special components.
• Determine whether the project involves drinking water, food processing, gas service, or other industries requiring certification.

2) Pressure and Temperature

• Confirm the normal operating pressure and whether pressure fluctuations or water hammer are expected.
• Confirm the continuous operating temperature rather than only the maximum instantaneous temperature.
• Verify that the selected materials meet the required pressure, temperature, and mechanical strength.

3) Material Matching

• Verify the valve body material and sealing material separately rather than focusing only on the valve body.
• Confirm that the sealing material is suitable for the process medium, operating temperature, and operating frequency.
• For corrosive, high-temperature, high-pressure, or high-cycle applications, evaluate whether higher-grade materials are required.

4) Installation and Project Requirements

• Confirm whether the installation environment is indoors, outdoors, coastal, or within a chemical plant.
• Determine whether additional corrosion protection or higher-grade materials are required.
• Consider project certifications, expected service life, procurement cost, and long-term maintenance costs together.

9. Conclusion

There is no universally superior valve material—only the material best suited to the operating conditions.
Based on our project experience, the factor that most often determines valve service life is not the valve design itself, but whether the material matches the actual operating conditions. Spending more time on material selection at the beginning of a project can significantly reduce future maintenance, downtime, and replacement costs.

If you are not sure which valve material is suitable for your application, feel free to submit your project requirements and operating conditions. Our engineering team will evaluate the most appropriate material solution and provide practical recommendations before procurement.