Galvanized pipe elbows play a crucial role in connecting and directing the flow of air, fluids, or gases in various systems.
Here are some common techniques for fabricating galvanized elbows：
Segmented Elbows:
In this approach, sections, also refers to as “gore,” are sliced and shaped. These pieces are subsequently pieced together, using either welding or riveting techniques, to fabricate the elbow. Segmented elbows offer flexibility, accommodating different curvatures and inclinations. Nonetheless, they entail substantial labor and may possess seams prone to leakage.
Press Brake Forming:
A press brake apparatus is employing to curve the sheet metal into the desired elbow configuration. This method is ideal for generating substantial batches of elbows while maintaining uniform excellence. Nonetheless, its capabilities regarding achievable radii and angles might be somewhat constrained.
Roll Forming:
Roll forming involves guiding the sheet metal through a sequence of rollers, gradually shaping it into the desired elbow form. This method ensures consistent bending throughout the process, thanks to its gradual nature. It’s commonly using for creating elbows with specific radii and angles.
Here are the steps involved in creating both seamless and welded 90 degree galvanized elbow:
Manufacturing Process of Seamless Elbow:
Heating Bending: One common method for seamless elbows is hot mandrel bending. Here’s how it works:
- Straight steel pipes are heated to an elevated temperature.
- The pipe is then pushed, expanded, and bent using inner tools (mandrel) step by step.
- Hot mandrel bending allows for a wide size range of seamless elbows.
- Advantages include smaller thickness deviation and stronger bending radius.
- Fewer welds are needed, enhancing pipe quality and usability.
Cold Bending: An alternative method is cold bending:
- Straight steel pipes are bent at normal temperatures using a bending machine.
- Suitable for pipes with an outer diameter of 17.0 to 219.1 mm and wall thickness of 2.0 to 28.0 mm.
- The recommended bending radius is 2.5 times the outer diameter (Do).
- Cold bending produces small-radius elbows, but internal packing with sand prevents wrinkling.
Manufacturing Process of Welded Elbow:
Welded elbows are mading from steel plates, resulting in a visible weld seam.
Here’s how they’re producing:
- Molding: A mold shapes the steel plate into the desired elbow form.
- Welding: The seam is welding to create a finished steel elbow.
Inspection is crucial due to the welded nature of the elbows. A meticulous examination of the welding joint is imperative. Non-destructive testing (NDT), particularly X-ray inspection, is frequently employed for this purpose.
The selection of fabrication technique relies on variables such as the intended use, material thickness, and production demands. Galvanized steel elbows serve as indispensable elements across diverse sectors, including HVAC, automotive, and aerospace industries.