Galvanized & Stainless Steel Ductwork

US Duct provides A FULL LINE of standard and special fabricated industrial ducting, including galvanized ductwork, stainless steel ductwork, and carbon steel. Just tell us your application and requirements — US Duct is fully equipped to provide custom galvanized and stainless steel ductwork to suit your specific needs.

In order to satisfy the diverse needs of our customers, we offer a large range of options beyond stainless steel ductwork. For instance, we offer products in a variety of sizes beginning at 3”. Our options for gauges range from 24 GA to 3/16” thickness.

In addition to providing all of these options, we ensure that you receive every component that you need from us. We offer a full range of standard and special design products. We can also supply you with all types of joining methods, including flanges, raw ends, airtight clamp-connect tubing, and rolled-lip (clamp together) ducting.

types of ductwork: clamp together duct, flanged duct, US Tubing

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Types of Industrial Ductwork

Clamp Together Duct — "Rolled Lip" Duct

US Duct's Clamp Together Duct system utilizes a rolled lip that is formed at the end of all parts. The lips (think a small version of a 55 gal barrel) of the mating parts are joined together with a gasketed, over-center clamp. The clamp pulls the ends together and envelopes them inside the sealing gasket. ALL parts and special hoods are available with rolled lip. The duct is available in galvanized or SS and in most gauges (depending upon diameter). Using the combination of a separate 11" long adjustable sleeve and/or the integral adjustable collar on each fitting, the US Duct Clamp Together system is infinitely adjustable. This feature along with the clamp enables the novice or professional to reduce installation time by 70%.

US Tubing — Airtight and Leak-Free

Providing the tight seal of flange connections and the convenience of Clamp Together Duct, US Tubing duct offers fully welded construction and Vanstone-gasket and clamp connecting system that creates a totally leak-free duct system for those applications that cannot have leakage: Oil Mist, positive pressure systems, food processing and many more.

Flanged Ductwork — Angle Rings or Mating Flanges

Flanged duct refers more to the joining method than the actual duct. Flanges (a.k.a. angle rings or mating flanges) are rolled angle iron with specifically punched holes. Bolts are used to "pull" the flanges together. Flanges and the duct are available in all sizes — 3" and up, in black iron, galvanized or SS. The duct fabrication and welding are based upon the customer's need and request. There are several options for affixing the flange to the duct.

Spiral Ductwork — Longer Runs and Fewer Connections

Spiral ducting is inexpensive and a great consideration for long runs of ducting. It is a definite consideration for duct sizes between 16" and 36" where there are long runs with few fittings.

A Word About Stainless Steel Ducting

All ducting steels have the same basic iron and carbon composition, but stainless steel ductwork also contains a healthy dose of chromium — the alloy that gives stainless steel its famous corrosion resistance.

There are multiple grades under the stainless steel umbrella, each with slightly different alloy composition, and therefore slightly different physical characteristics. Stainless steel must contain at least 10.5 percent chromium. Depending on the grade, it may contain much higher chromium levels, and additional alloying ingredients like molybdenum, nickel, titanium, aluminum, copper, nitrogen, phosphorus and selenium.

The two most common stainless steel grades for ducting are 304 and 316. The key difference is the addition of molybdenum, an alloy which drastically enhances corrosion resistance, especially for more saline or chloride-exposed environments. 316 stainless steel contains molybdenum, but 304 doesn’t.

For outdoor and some corrosive ductwork applications, stainless steel is an ideal corrosion-resistant material, but it will only withstand long-term exposure if the grade is appropriate for its environment. 304 is an economical and practical choice for most environments, but it doesn’t have the chloride resistance of 316. The slightly higher price point of 316 ducting and components may be well worth it in areas or applications with high chloride exposure. Each application for stainless steel ductwork has its own unique demands and needs a stainless steel that’s up to the task.

A Word About Galvanized Ductwork

Most ductwork manufactured with galvanized metal is hot-dip galvanized, a process of coating steel with a thin zinc layer. The steel passes through a molten bath of zinc at a temperature of around 860°F (460°C). When exposed to the atmosphere, pure zinc reacts with oxygen to form zinc oxide, which further reacts with carbon dioxide to form zinc carbonate, a dull grey, relatively durable material that stops further corrosion in many circumstances, protecting the steel below from the elements. Galvanized steel is widely used in ductwork applications where rust resistance is needed and can be identified by the crystallization patterning on the surface (often called a “spangle”).

The process of hot-dip galvanizing results in a metallurgical bond between zinc and steel with a series of distinct iron-zinc alloys, creating a versatile and affordable material for manufacturing ductwork and duct components. The resulting coated steel can be used in much the same way as uncoated. Galvanized steel is suitable for high-temperature applications typically up to 392°F (200°C). Use at temperatures above this level can result in the peeling of the zinc at the intermetallic layer. Galvanized sheet steel ducting is commonly used in most dust collection ducting applications.

A Word About Teflon®-Coated or Painted Ductwork

Sometimes, the duct material is sufficient for the needs of the system. Other applications have more complex requirements and need to be able to convey abrasive or corrosive materials with ease. US Duct offers a comprehensive line of available coatings and finishes for your ductwork including Teflon®. From simple appearance needs (painting and powder coating) to complex chemistry (abrasion resistance and nonstick) applications, US Duct can provide your duct coating needs.

See More Coating Options

Whether it's simply selecting the right material for your application, or if additional ductwork coatings are required, we've got you covered.

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