If you've worked with any kind of fluid processing system, then you are familiar with ball valves and the crucial job they do. Ball valves are quarter-turn valves that are often made with full-bore designs. This means they can completely stop flow when closed and will not hinder flow when opened. This is valuable with flow rate and pressure are important to the application. Stainless steel is one of the strongest and most resilient materials out there, with top-notch pressure and temperature resistances. There are too many applications for stainless steel ball valves, but in this article we will look at some of the most common. But first, what makes stainless steel so special?
What is Stainless Steel?
The reason there are so many uses for stainless steel ball valves is that it is a fantastic material. It is tougher than cast iron, ductile iron, brass, and copper when it comes to pressure rating and temperature tolerance. Stainless steel competes with carbon steel on many fronts, but beats it by a mile in corrosion resistance. For this reason, applications for stainless steel ball valves are typically demanding in one or more area (corrosion, temperature, pressure).
Stainless steel is a fantastic material that is difficult to beat, but it does have one major drawback: price. There is a major price jump from iron valves to steel valves, but it is warranted! The price jump is reflected by a jump in quality from one material to another. Stainless steel is the best of the best, with high pressure tolerance, temperature limits, and corrosion resistance.
Not all stainless steel is created equal! There are several grades of stainless steel, the most common being 304 and 316. These numbers represent the chemical makeup of the material, which is composed of at least 50% iron and 10% chromium regardless of grade. Typically, the more chromium in the mix, the higher the corrosion resistance. 304 stainless steel resists corrosion fairly well due to the addition of nickel in the mix. 316 stainless steel is better equipped for harsh environments, though. It has higher levels of nickel and a a substance called molybdenum added to the mix. Both nickel and molybdenum work with the chromium to make the alloy more resistant to chlorides, which are found in marine environments. Ball valves made of 316 stainless steel are some of the most corrosion-resistant you can find.
Applications for Stainless Steel Ball Valves
We sell a wide range of valves, but what are stainless steel ball valves used for, specifically? Let's find out! Below are a few jobs where stainless steel shows its worth.
The process of refining crude oil into usable outputs is a complicated one that we will not delve too far into today. However, it is a great example of a job that only stainless steal ball valves can do. Crude petroleum can contain water, carbon dioxide, sulfur, and all kinds of microorganisms. These make it a very corrosive substance. It will slowly break down metal over time, so you must get valves and pipes that will be able to withstand it for the longest amount of time. Stainless steel ball valves will hold up longer than other materials, so they are the obvious choice.
Some applications take place in or near seawater, such as desalination. Marine environments are corrosive and harmful to all types of materials, but because they involve water, they affect metals most of all. In these types of applications, many like to use plastic ball valves that may have better resistance to water and harsh chemicals than most metals. The problem with this is that plastic valves lack the ability to perform under high pressures and extreme temperatures. Stainless steel ball valves handle intense conditions with ease. And with the proper maintenance, a stainless ball valve can have a long lifespan around seawater.
Finally, we will take a quick look at brewing. Stainless steel ball valves are used in just about every brewery. Most commonly located on the kettle, stainless ball valves allow the user to control liquid flow during transfers. The reason stainless steel is necessary is it comes in direct contact with wort, the liquid extracted during the mashing process when brewing beer or whisky. This is a corrosive liquid substance that would wear down valves made of iron. Since plastic valves can't handle the temperatures encountered in brewing, stainless steel is the best option! Image on the right courtesy of LearnToBrew.com.