What are the standard sizes for stainless steel pipe?  What does schedule mean, and why is it used when talking about pipe sizes?  These questions and more will be examined in today’s post.

Stainless steel offers several advantages over other metals, and these benefits make it an excellent material for a variety of demanding applications.  Whether it’s superior strength, corrosion resistance or ease of manufacturing, more solutions are relying on stainless.

That’s why understanding the sizing system for pipe is important.  It’s also why working with an experienced material supplier who knows the industry terminology is critical.

What are the advantages of stainless steel pipe?

There are two primary attributes that make stainless steel extremely attractive for a wide variety of industries: excellent strength and corrosion resistance.  This is especially true when talking about stainless pipe.  Other benefits include stainless steel’s thermal and chemical resistance, cleanliness and lower maintenance costs.

When picking out a material, you’ll need to take careful stock of the specific requirements for your field and application. Stainless offers tremendous strength, versatility, weldability and a lack of reactivity to several chemicals, making it a primary choice for pipe material.  Another benefit that’s often overlooked is that it requires a significantly lower preparation time prior to fabrication compared to carbon steel.

When working in a high temperature environment, stainless is a great choice; it’s also resistant to UV radiation.  Combining these attributes with its excellent corrosion resistance, stainless steel is often the only option when dealing with marine or other extreme environments.  It’s even possible to apply treatments that make stainless pipe resistant to microbial growth. Stainless is commonly used in the food and beverage, wastewater treatment and healthcare industries.

Another lesser known but valuable trait is that stainless equipment tends to retain its resale value as it ages.

Seamless Versus Welded 

When picking out what type of stainless steel pipe to use, one of the decisions to make is whether seamless or welded is required.  In general, welded pipe costs less and is more readily available than seamless, as it’s easier to manufacture. However, depending on the application, welded piping may not be an option.  The weld’s seam is a weak spot in the pipe, creating a risk of rupture in pressurized applications.  Recent advances in manufacturing techniques have improved welding integrity, but it is still an issue. Pressure-related specifications will need to be followed prior to settling on materials.

When picking a material, options will likely include aluminum, copper, carbon steel or plastic.  Aluminum, while it’s lightweight, is not as easy to weld and typically is not as corrosion resistant.  Copper is durable and heat resistant, but much more expensive. Carbon steel is prone to corrosion, while plastic rarely can match the durability afforded by stainless steel.

What do we mean by pipe schedule and nominal pipe size?

The size of pipes can be described in several different ways.  Consider a pipe’s outside diameter, wall thickness and inside diameter; when purchasing pipe, there are two size indicators that figure all the above at once.  These are the nominal pipe size and the schedule number.  Industry standards to refer to pipes by their schedule, such as schedule 40 and schedule 80; these are among the most common sizes.

In 1927 the American Standards Association created a system that designated wall thicknesses based on steps between the sizes. The nominal pipe size is referenced, and the term schedule was invented to specify the nominal wall thickness of pipe.

First, the nominal pipe size refers to the outside diameter.  Typically, this won’t be an exact measurement, but a reference number that can be used to figure out the exact dimensions. Complicated right?  As an example, if the nominal pipe size is 3, then the actual outside diameter should be 3.500 inches, and an NPS of 2 indicates the outside diameter is 2.375. Please follow this link to access a chart with the various standard diameters here: https://en.wikipedia.org/wiki/Nominal_Pipe_Size

Knowing only the nominal size doesn’t indicate much about the pipe.  Equally as important is knowing the pipe schedule. The schedule determines both the inside diameter and the wall thickness for a nominal pipe size.  Likewise, only knowing the schedule without the nominal pipe size also does not provide enough information.  With the nominal size and the schedule, one can figure out the exact wall thickness, as well as both the inside and outside diameters of the pipe. 

What are the differences between Schedule 40 and Schedule 80 piping? 

As mentioned, schedule 40 and schedule 80 are probably the two most common pipe schedules.  The major differences between the two include wall thickness, inside diameter and weight.  Schedule 80 has a larger wall thickness, smaller inside diameter and increased weight when compared to Schedule 40, assuming they both have the same nominal pipe size. 

The above referenced chart includes sizing information for the various standard schedules, which range from schedule 5 to schedule 160.

Your Technical Services Provider

When it comes to pipe size, there are many options to choose from.  When determining what schedule pipe and what material is just right for the next project, why not team up with the professionals?  Clinton Aluminum’s dedicated team of experts has the experience and familiarity to answer all questions about pipe dimensions and materials.  Contact us today to speak with one of our knowledgeable and friendly representatives.

Benefits of 316 vs. 304 Stainless Steel

While there are no visible differences between 304 and 316 stainless steel, there are distinctive chemical differences – the most crucial difference being their chemical compositions. 304 stainless steel contains 18% chromium and 8% nickel. In contrast, 316 stainless steel contains 16% chromium, 10% nickel, and 2% molybdenum. The chemical distinction between these two grades of stainless steel is of great importance when considering their intended uses.

304 Stainless Steel Properties & Applications

The majority of stainless steel utilized globally is grade 304. There are multiple reasons for its popularity, including:

• 304 stainless steel is durable and is corrosion and oxidation resistant, meaning it can endure average exposures.
• Its melting point ranges from 2,550° F to 2,650° F, allowing it to withstand very high temperatures.
• 304 is also valued for its high tensile strength of about 621 MPa (90 ksi).

304 stainless steel’s chemical makeup of 18% chromium and 8% nickel makes it a good choice for many common applications, which include:

• Kitchen equipment & appliances
• Water piping
• Indoor electrical enclosures
• Auto moldings & trim
• Wheel covers
• Storage tanks

316 Stainless Steel Properties & Applications

304 and 316 stainless steel share many properties. However, it is the added properties that set 316 stainless steel apart.

• The addition of molybdenum to 316’s chemical makeup improves its resistance to harmful acids, alkalis, and chloride pitting. This increases its longevity and provides crucial protection for essential components.
• Its high percentage of chromium and nickel, indicative of austenitic stainless steel alloys, provides increased strength and corrosion resistance in some of the most punishing environments.

316 stainless steel’s material composition of 16% chromium, 10% nickel, and 2% molybdenum allows it to be used in applications that require superior corrosion resistance and stringent hygiene and cleanliness requirements. Some of the most common applications are:

• Chemical equipment
• Pharmaceutical equipment
• Outdoor electrical enclosures
• Marine parts
• Stainless steel baskets
• Medical surgical equipment
• Stainless steel floats

Benefits of Using 316 Stainless Steel

When salt and other chlorides are an exposure and lasting durability is desired, the benefits of using 316 stainless steel over 304 are clear.

Durability

Not only tough, but also versatile, 316 stainless steel is an excellent choice for use in applications such as custom wire baskets. These baskets are often subject to harsh, high-impact conditions, and 316 stainless steel continues to deliver durability in these environments year after year.

Corrosion Resistance

316 stainless steel’s added chemical component, molybdenum, makes it much more corrosion resistant than 304 or other stainless steel alloys. This allows 316 stainless steel to be used in highly acidic environments that other steels can’t tolerate without incurring damage. 316’s corrosion-resistant properties also make it ideal in pharmaceutical and medical applications due to its ability to withstand the strong disinfectants and high temperatures needed to sterilize equipment.

Sea and Marine Applications

Exposure to salt and chlorides can wreak havoc on 304 and other stainless steel alloys. Salt can cause 304 stainless steel to rust by eroding its protective oxide layer, and 304 steel is also more easily pitted from the effects of salt and chlorides. However, 316 stainless steel has all of the desirability properties of 304 stainless steel, but with the added benefit of molybdenum, which allows it to withstand exposure to salt and chlorides without breaking down.

Bergsen Metals Stainless Steel Products

While 316 stainless steel has all of the benefits of 304 stainless steel and many additional benefits as well, it all comes down to the qualities needed for a particular application.

Regardless of your stainless steel needs, Bergsen Metals offers a complete inventory of stainless steel products in a wide variety of grades and sizes. View our stainless steel products, request a quote, or contact us for more information on how we can move your business forward with our quality stainless steel products and exceptional customer service.