Choosing the correct materials in manufacturing valves is crucial for safety, reliability, and cost-effectiveness. Yet it can be very complicated, depending on many factors. Identifying the correct material has become paramount when working with customers to ensure safety.
There are thousands of metallic material grades to choose from, each with unique properties, costs, and availability. This comprehensive list must be pared down to a manageable level, primarily based on historical usage and consideration of customer requirements.
Each material and grade are limited by its strength, usable and permissible temperature range, corrosion resistance, and in some materials, section thickness. A fundamental goal is to select the most cost-effective materials that will provide suitable performance in service. Over engineering materials could lead to extended costs for the customer. While under spec-ing can result in reduced performance or premature valve failure, which can be dangerous and costly to the end user and damage both the valve manufacturer’s and the end user’s reputation.
Valve body material must be matched to the pipe material to which it will be connected. Since pipes are typically made to a different standard than forgings and castings, their specifications may be slightly different, but the basic properties must be the same, including chemical composition and heat treat condition.
Valve internals are typically selected to be more corrosion-resistant than the body, and often require higher strength depending on the application. They also require a coating or surface hardening treatment to prevent wear and galling.
The basic factors in material selection are:
- Customer’s pipe material
- Type of valve
- Design pressure and temperatures (low and high)
- Fluid composition
- Torque requirements for the operator
- Welding
The following questions should be asked to narrow down the material selection:
- Is the material readily available in our supply chain?
- Is it listed in design codes such as ASME B16.34 or ASME Section II Part D?
- Is impact testing required, and does the candidate material have sufficient toughness at the minimum design temperature?
- Are materials compatible with each other regarding thermal expansion?
- Should the component raw material be a casting, a forging or hot rolled bar?
- What are the relative costs of purchasing and machining?
- Are there additional industry standards or customer-specific requirements for composition, heat treatment, mechanical properties, or other testing?
- For parts that are subject to wear or galling, are they compatible with the intended coating or surface treatment?
- Does a coating have sufficient corrosion or wear and galling resistance?
Considering all these factors when choosing materials leads to robust and reliable valve performance, which results in satisfied customers and profitable sales and further ensuring that safe operations and minimum downtime are achieved.
At ValvTechnologies our process to achieve zero leakage valves begins with close attention to the materials we select. We ensure our engineered-to-order valves cater to our customers’ unique and specific needs no matter how unique or severe. To learn more about our valves, please visit: https://www.valv.com/products/
About the Author
Steve Swinney is our Principal Metallurgist at ValvTechnologies.
His 35 plus years of expertise in the field is invaluable when evaluating customer material requirements and when selecting metallic material options for applications in our zero leakage valves.
Steve’s background includes a B.Sc. in Metallurgical Engineering from the Colorado School of Mines, work experience in the aerospace and oil and gas industries, and for the past 13 years supporting in ValvTechnologies diverse customer base.
