Where must the bend be located if the pipe has a longitudinal weld?

• A. Neutral axis
• B. External surface
• C. Internal surface
• D. End of the pipe

Answer: (A)

The bend must be located at the neutral axis for a pipe that has a longitudinal weld because this is the point where the material does not experience tensile or compressive stress during bending. In a cylindrical pipe, the neutral axis runs along the center of the wall. Positioning a bend at the neutral axis helps prevent failure or deformation along the weld, which is typically a potential weak point due to the concentrated stresses in that area.

If the bend were located at either the external or internal surfaces, it could lead to increased stress concentrations along the weld seam, raising the risk of crack formation or material failure, especially under operational loads. Locating the bend at the end of the pipe would not make structural sense, as it does not align with standard practices that aim to minimize the risk of failure and maintain the integrity of the weld. Therefore, the proper location for bending a pipe with a longitudinal weld is indeed at the neutral axis to ensure optimal performance and safety.