Do the Q390B steel plates have Z-direction performance?

Q390B material is a low alloy high strength steel plate. Q390B steel plates have Z-direction performance.
Z-direction steel other names: Lamellar tear-resistant steel. Definition: Specifically refers to thick or extra-thick steel plates used in offshore oil platforms, ships or pressure vessels. The sulfur content in steel is extremely low and the form of inclusions Controlled steel that is less prone to layered cracks in the thickness direction.

Z-direction steel plate in China

Z15, Z25, and Z35 three levels are added after the steel number of our country to indicate the section shrinkage of the thick plate. Z direction is just one of the properties of steel plate, also known as "laminated tear resistance steel". In the steel structure using welding connection, when the thickness of the steel plate is not less than 40mm and it is subjected to the tensile force in the thickness direction of the plate, in order to avoid lamellar tearing during welding, a steel that resists lamellar tearing (commonly referred to as "Z direction" steel"). There is a lamellar tearing problem in thick plates, so the Z-direction performance test is required. Steel plates and shaped steels are formed by rolling. Generally, the steel used for multi-tall steel structures is hot-rolled. Hot-rolling can destroy the casting structure of steel ingots and refine the grains of steel.
 
The bubbles and cracks formed during the casting of the steel ingot can be welded under the action of high temperature and pressure, thereby improving the mechanical properties of the steel. However, this improvement is mainly reflected in the rolling direction, because non-metallic inclusions (mainly sulfides, oxides, silicates, etc.) inside the steel are pressed into thin slices after rolling, and remain in the steel plate ( Generally parallel to the surface of the steel plate), and the steel plate appears delamination (interlayer) phenomenon. This non-metallic sandwich phenomenon. Deteriorates the tensile properties of the steel in the thickness direction.
 
Z to steel. This steel plate is a steel that has been specially smelted and treated on the basis of a certain level of structural steel (called the parent steel). Its sulfur content is less than 1/5 of that of ordinary steels, and its section shrinkage is more than 15%. . The stress performance (mainly ductility) of the steel plate in the thickness direction is called Z-direction performance. The Z-direction performance of a steel plate can be obtained by conducting a tensile test on a sample, and is generally measured by the reduction in area. The Z-direction steel plate produced in China is marked by adding the Z-direction steel plate grade marks Z15, Z25, Z35 after the parent steel grade, and the number after the Z is an index (%) of section shrinkage.
 

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