Brief Introduction to Anti-brittle Fracture Performance of Packaging Steel Strip Wrap Container

Brief Introduction to Anti-brittle Fracture Performance of Packaging Steel Strip Wrap Container
　　The cylinder body of the steel strip staggered pressure vessel has no deep weld seam over the entire length, and the cylinder body and both ends are connected by inclined weld seams. This novel structure type makes this container have excellent anti-brittle fracture performance. This has been confirmed by long-term engineering applications.
　　 steel strip staggered pressure vessel, even if there are cracks in the inner cylinder, due to the following main advantageous factors, it can be ensured that the vessel does not undergo overall brittle failure.
　　 The stress level of the inner cylinder is reduced uniformly and an appropriate stress level is an important condition for the safe use of pressure vessels. The fracture analysis as described above shows that reducing the stress level has a significant effect on suppressing crack propagation.
　　 The theoretical analysis in Chapter 2 and previous experimental studies show that the prestress of the steel strip winding will cause the inner cylinder to be compressed in the axial and circumferential directions at the same time, and the prestress test device of the winding steel strip can be used to Ensure that the compression received has a certain uniformity and will not cause stress concentration. After the compression prestress and the tensile stress caused by the working pressure are superimposed, the inner cylinder can still be at a low stress level, and the possibility of crack initiation is very small.
　　The flat steel strip mainly bears the tensile stress and radial compressive stress in the longitudinal direction of the strip, and its thin thickness is conducive to the plastic flow of the material; the crack is completely passivated and it is extremely difficult to expand.
　　The inner cylinder and the steel belt have been improved. The material of the container has excellent fracture toughness, which is a prerequisite for preventing brittle fracture of the container. The above fracture analysis shows that improving the fracture toughness of the material also has a significant impact on the suppression of crack propagation.
　　The material used for the multi-layer wrap-up container is a 4-12mm thin steel plate, which has a low brittle transition temperature. Steel strip with better plasticity is commonly used in the inner cylinder of steel strip staggered pressure vessel
　　 (the thickness generally does not exceed 40mm), easy to manufacture, good quality, and has good fracture resistance. For example, China has tested the critical crack opening displacement of 15MnVR steel plates of different thicknesses, and found that the plate thickness has a certain effect on the fracture toughness. Under the conditions of the same chemical composition of the material and the rolling state, the thin plate and steel strip The initial fracture properties must be higher than the fracture toughness of thick plates.