top-of-page Rotary Bending The usual mode of bending is curvature around a straight-line radius (Figure 1). Through the thickness is a gradient of strains from maximum outer fiber tension (the outermost surface) through a neutral axis to inner fiber compression (the...
Evaluating sheet metal formability using computer software has been in common industrial use for more than two decades. The current sheet metal forming programs are part of the transition to virtual manufacturing that includes analysis of casting solidification and...
Normal vehicle use leads to repeated loading of components and joints. Stress concentrations in the body structure may lead to plastic strains at stresses below the yield strength due to cyclic fatigue. Conventional High-Strength Steel fatigue behavior correlates with...
A cut edge has four distinct zones with different characteristics: Rollover – The plastically deformed zone bent as the cutting tools contact the edge of the sheet surface. Burnish – The zone where the cutting tools penetrate into the sheet metal, prior to any...
Conventional Forming Limit Curves (FLCs) gained widespread industrial use since being introduced by Dr. Stuart Keeler in the 1960’s. Applications from feasibility analysis to stamping plant troubleshooting use these principles. The strain hardening exponent (n-value)...
Drawing is the sheet metal forming process where the punch that creates the part shape forces the sheet metal to pull in from the flange area. In contrast with stretch-drawing or stretch forming, little metal thinning occurs in pure drawing. There is not a generally...
Strength is defined as load divided by cross-sectional area. In a tensile test, the choice of when the cross-sectional area is measured influences the results. It is easiest to measure the width and thickness of the test sample before starting the pull. At any load,...
Most sheet metals have different “Global” and “Local” forming capabilities, so it is critical to understand their meaning to optimize grade selection, processing, and usage. Historically, most fabricators needed to consider only global formability when designing and...
Delayed cracking caused by hydrogen embrittlement results in decreased toughness, ductility, and load-bearing capacity of a material. It is a concern with some Advanced High-Strength steel (AHSS) grades. Three triggers must be present for there to be an embrittlement...
Many demands are placed on automotive body structures which influence the material selection process. The impact on safety, manufacturability, and longevity are among the most critical, with each of these balanced against cost and environmental concerns. Formed sheet...