Long radius bends for steel pipe can also be made in smaller sized pipe by the use of _____________.

• A. Wrinkle bending
• B. Mandrel bending
• C. Roll bending
• D. Heat bending

Answer: (A)

Wrinkle bending lets you form long-radius bends in small-diameter steel pipe by creating a controlled series of wrinkles in the bend area. Those wrinkles provide extra accommodation in the metal so the pipe can curve gradually without kinking, effectively achieving a larger bend radius than a plain bend on the same small size. This method is handy when you need a gentle curve but don’t have the equipment for roll bending or mandrel bending on small pipes. Roll bending is more suited to larger pipes; mandrel bending focuses on preventing collapse rather than extending the bend radius; heat bending relies on heating the material and doesn’t inherently produce a longer radius.