Size should be slightly larger; the general selection is more widespread. "a" or the mean value refers to the reduction ratio of the cross-sectional area at the necking fracture to the original cross-sectional area, indicated as a percentage. The larger the "a" or the mean value, the more it indicates cast iron bars.PipeThe better the plasticity. The y-value can also reflect the plastic deformation ability of the necking part of the steel under three-directional tensile stress conditions, which is relevant to considering the resistance in the thickness direction against lamination. The cold bending property is tested through cold bending tests, as shown in Figure-4. During the test, the specimen needs to be bent to 180 degrees. If the outer surface of the specimen does not show cracks or delamination, it is considered合格. Cold bending tests not only directly verify the bending deformation ability or plasticity of the steel but also reveal the metallurgical conditions within the steel, such as sulfur and phosphorus segregation, and the contamination of sulfides and oxides. These factors will reduce the cold bending property of the steel. Therefore, the cold bending property is an integrated indicator for determining the plasticity and quality of the steel's bending performance. The steel properties demonstrated by the impact toughness and tensile tests, such as strength and plasticity, are static functions, while the toughness tests reflect the dynamic properties of the steel.