Flanges can be manufactured using one of three main techniques – casting, forging, or cutting from rolled plate metal. No matter what technique is used, the basic procedure always involves processing the raw material and then forming them into the appropriate shapes. Flanges will then be sealed and finished to meet applicable standards before being shipped to a customer.
Raw Materials Used in Flange Manufacturing
Manufacturing flanges starts with the raw material, which will either be from the United States or imported from areas such as India, China, and South Korea. These materials must go through rigorous testing before being purchased. A Mill Test Report (MTR) declares any chemical and physical properties in the material and verifies that it has met the minimum standards for use.
The most common materials used for flange manufacturing are mild/carbon steel, ductile iron, aluminum, and stainless steel.
Common Manufacturing Methods
Flanges are manufactured by first shaping, then machining, drilling, and finishing to the correct specifications. Cast, cut, and forged machining methods may all be used in the production of flanges. Forged flanges are generally more resistant to wear, but more expensive to produce. Cast flanges are cheaper to produce but may fail under high-pressure situations. Cut flanges are the weakest of the groups.
Finishing and Coatings
The roughness or smoothness of a flange, as well as any serrations, is handled after a flange has been cut, cast, or forged. The finish of a flange will vary based on the application. Finishes such as smooth, rolled, machined, and continuous or concentric serrated are available. Protective coatings are then applied before the pieces are shipped.
The Bottom Line
There are many different kinds of flanges with different strengths and weaknesses, so doing your own research or speaking with an expert prior to purchasing is always a good idea. Cut, cast, and forged flanges all have their specialties and work best under different conditions. Cut flanges are generally the weakest of the bunch, but they have their uses in low-pressure projects.
Flanges are often used in high-pressure situations as well, especially forged flanges. A weld neck flange has been successfully used at pressures up to 5,000 psi. It’s important to understand the stresses and wear the flange will face before you decide which piece to order to complete your project.
Give us a call at Lynco Flange & Fitting and we will help you select the right materials for your next project.