Material selection across the whole connection
metal duct elbows
| Round nominal bore (mm) | 100 / 160 / 250 / 400 |
|---|---|
| Rectangular opening W × H (mm) | 300 × 200 / 500 × 300 / 800 × 400 |
| Material families | Galvanized steel / stainless steel / aluminum |
| Construction | Pressed, segmented, folded or welded, according to material and duty |
| Connections | Spigot, clamp or flange |
| Selection inputs | Air contaminants, temperature, moisture and cleaning method |
Alloy or grade, wall thickness, surface treatment and seal materials are specified for the selected construction.
Metal duct elbows can be configured for the air stream, installation environment and maintenance requirements.
Metal describes a broad family of duct elbows, not a single performance level. The useful comparison is how the body and its connections behave in the intended environment, including conditions outside the duct and the products used to clean it.
Compare the material families
Galvanized steel
A common choice for general ventilation, with a protective zinc coating and many familiar joint forms. Cut edges, damaged coating and persistently wet areas deserve attention. Aggressive chemical exposure requires a separate compatibility assessment.
Stainless steel
Useful where the selected grade and surface finish suit the air stream or cleaning regime. The grade, weld condition and crevices matter; stainless steel is not immune to corrosion, especially when deposits retain contaminants.
Aluminum
A light sheet material used in suitable ventilation fittings. Its forming, joining and support details differ from steel. Select the alloy and exposure conditions explicitly instead of assuming all aluminum fittings suit every extract process.
The least compatible part can govern the assembly
A stainless body can still be joined by a gasket that swells in the process atmosphere, or by fasteners unsuitable for a damp environment. Conversely, a durable gasket cannot compensate for a damaged shell. Specify the joint as an assembly, including sealant, fasteners and any insulation in contact with the surface.
When metals are mixed, examine the potential for moisture to remain at the contact. The appropriate isolation or protective detail depends on the materials and environment. Keep those details in the purchase specification rather than relying on the installer to improvise.
Specify evidence that answers the real question
If material traceability is important, identify the required grade documentation and fabrication records in the order. A bright finish, a magnet check or the word industrial does not establish chemical compatibility or a pressure rating. For cleanable extraction, examine internal seams and access as carefully as the external finish.
See aluminum duct elbows for lightweight connections and industrial duct elbows for particle-carrying duties.
Metal duct elbows can be configured for the air stream, installation environment and maintenance requirements.