Cracking down on weld cracks--Knowing how cracks form is half the battle

摘要

One of the primary objectives of any weld fabrication is to prevent weld defects, especially cracks. Cracks are the most severe of all weld defects and are unacceptable in most circumstances. Rework robs the company of precious time and material (that is, money), so prevention is the primary concern.Cracks don't always happen immediately after welding, and certain cracks, such as the under-bead variety, may not be open to the weld surface. Cracks can develop over time after the weld has been subjected to loads while in service. Tensile and fatigue loads; bending, twisting, or flexing; as well as hot and cold expansion and contraction all can occur long after welding, be it two days, two months, or even two years.