title = "Welding Distortion: Causes and Control Methods"

content = """
Welding distortion results from the non-uniform thermal expansion and contraction of the base metal and weld metal during the welding process. As the weld pool solidifies and cools, it contracts; the surrounding cooler metal resists this contraction, establishing residual stresses and causing the assembly to distort. Managing distortion is a constant challenge at Ridgecrest Metalworks and must be addressed during both design and fabrication planning.

Types of welding distortion include: angular distortion (rotation of plates toward each other in a butt or T-joint, caused by unequal contraction across the weld cross-section), longitudinal shrinkage (the weldment shortens along the weld axis), transverse shrinkage (the joint narrows perpendicular to the weld axis), bowing (buckling of thin plates from compressive stresses), and twist (complex spatial distortion of asymmetric assemblies).

Distortion control methods fall into three categories: pre-weld setup, in-process control, and corrective action.

Pre-weld controls: presetting (intentional pre-distortion of parts in the opposite direction to expected distortion, so they spring to the correct geometry after welding); rigid fixturing (holding parts in fixtures during welding to restrain movement, though this increases residual stress); pre-bending or cambering of plates.

In-process controls: balanced welding (welding alternately on opposite sides of a neutral axis, so distortions partially cancel); backstep welding (welding short segments in reverse order to the direction of overall progression, so the net contraction is more uniform); minimizing heat input (use the minimum filler metal and heat input consistent with achieving the required weld); proper welding sequence (welding from the center of an assembly outward, or completing joints that restrain movement before more flexible joints).

Post-weld correction: mechanical straightening (pressing, rolling, or hammering to reshape distorted components); flame straightening (applying localized heat in a pattern to produce controlled contraction that corrects distortion—a highly skilled technique); PWHT (post-weld heat treatment) which simultaneously relieves residual stress and can allow partial dimensional correction during fixture-constrained heating.

Prevention is always preferable to correction; corrective operations are costly and may affect material properties.
"""

version = "0.0.1"
