可以参考
Low alloy steels are metallic materials which usually contain less than 5% alloying elements and show good strength, ductility, toughness and weldability. Low alloy steel plate is often called as structures plate, bridge plate, special steels plate and low-temperature pressure vessel plate. The latter is widely used in low-temperature pressure vessels and has been widely used in chemical, water tank and construction industries.
Given the complexity of the use of low alloy steel, the relative standards and quality requirements are also more stringent. GB3531-1996 is one of the common standards for low alloy steel plates. Generally, this standard requires that the low alloy steel plates used in the production of low temperature pressure vessels must have good toughness and high dimensional accuracy.
In order to meet the requirements of high performance, GB3531-1996 requires high alloy content in low alloy steel plates. Alloying elements used in low alloy steel plates mainly include chromium, molybdenum, nickel, manganese, tungsten and other elements, accounting for a total of at least 5% of the total weight of the metal. The total amount of alloy elements in the steel should not exceed 7.5%. At the same time, in order to improve the performance of low alloy steel plate, the addition of these alloy elements can optimize the balance between strength and plasticity, reduce cracking risk, and realize the best performance of low alloy steel plates.
In addition, in order to guarantee the quality of low alloy steel plate, it is necessary to strictly control the chemical component and technical requirements in the process of steel production. Generally speaking, the minimum requirement of GB3531-1996 for the yield strength of hot rolled low alloy steel plate shall not be lower than 245MPa, and the tensile strength of the steel plate shall not be lower than 415MPa. Fatigue strength, impact toughness and other properties of steel must also meet the requirements of standardization.
Moreover, for the production of low temperature pressure vessel, it is also necessary to strictly control the tightness of steel and steel plate. Surface quality requirements of steels should also be taken into consideration. Generally, the allowable base extension deviation of the steel plate should not exceed 2.5%, and the surface roughness of the steel plate should not exceed 2.5mm. At the same time, it is necessary to ensure that there are no defects such as crack and crack on the surface of the steel plate.
In conclusion, the quality of low alloy steel plates used for the production of low temperature pressure vessels should meet the requirements of GB3531-1996. Good chemical composition, good toughness and high dimensional accuracy are important factors for the successful production and use of low temperature pressure vessels. In order to ensure the performance and quality of low temperature pressure vessels it is necessary to ensure strictly the production quality of low alloy steel plates.
