Z-steel

Also known as "lamellar tearing resistance steel (lamellar tearing resistant steel)", which usually have the z-direction.welded connections in steel structures, when the plate thickness is not less than 40 mm and when subjected to pull along thickness direction, lamellar tearing during welding to avoid, lamellar tearing resistance of steel should be used (usually referred to as "z-steel"). Plate lamellar tearing problems exist, so to move z to the performance test.

Steel plate and steel through roll-forming, generally used in high-rise steel structure for hot-rolling of steel, hot rolled ingot casting can damage tissue, refined steel grain. Bubbles formed during the steel ingot pouring and crack, can be welded under high temperature and pressure, so as to improve the mechanical properties of the steel. However this improvement mainly reflected on along the rolling direction, within the steel non-metallic inclusions (mainly sulphides, oxides, silicates, etc) after rolling is laminate, survives in the plate (usually parallel to the surface), leaving the plate appears layered (sandwich). This phenomenon of Nonmetal sandwich. The steel thickness tensile properties deteriorate. Therefore the mechanical properties of steel plates in three directions are different: along the rolling direction best performances perpendicular to the rolling direction slightly worse; thickness as.
Thick steel plates more susceptible to lamellar tearing in General, because thicker plate, non-metallic inclusion, the more, and the welds are thicker, bigger the welding stress and distortion. To solve this problem, the best use of z-steel. This kind of structure steel plate is at a certain level (called the parent-level steel) on the basis of specially ye practice, handling steel, its sulphur content for General steel 1/5, section obtainable at 15%. Mechanical behavior of steel plate thickness (mainly ductility) is called the z-direction properties. Z performance of steel plate by tensile tests, generally measured by contraction of cross sectional area. Mark z steel production in China is in a parent-level steel to the plate, followed by the z-grade flag Z15, Z25, Z35,Z, after the words the index number for the section shrinkage (%).