Analysis of common defects in tube sheet manufacturing

Common defects in tube sheet manufacturing mainly include cracks, deformation, and expansion joint problems. Cracks are often caused by improper forging temperature control or abnormal material composition, while deformation is related to heat treatment processes and processing parameters. Expansion joint problems involve temperature control and process selection.

I. Crack Defects
Causes: Forging temperature too high or too low, abnormal content of elements such as Mo/Cu in the material, or improper heat treatment process (e.g., heating rate, holding time).
Case Study: A tube sheet on a desorption tower in a chemical plant developed curved cracks after 400 hours of use due to defects in the forging process.

II. Deformation Defects
Causes: Improper control of heat treatment processes (e.g., heating rate, holding time) or processing parameters (e.g., bending support force).
Case Study: In the tube hot bending process, insufficient sand filling or uneven heating led to inward radial concavity on the inner side.

III. Expansion Joint Problems
Causes: Expansion joint temperature too high (>300℃) leading to stress relaxation, or improper process selection (e.g., the sequence of expansion joint and welding).
Case Study: During the expansion joint of tubes and tube sheets, improper temperature control led to connection failure.