Steel plate for high toughness 15CrMoR pressure container

Abstract

The invention relates to the manufacturing field of steel for a chrome-molybdenum heat resistant pressure container, in particular to a steel plate for a high toughness 15CrMoR pressure container. The steel plate is prepared by the following components in percentage by mass: 0.14-0.18% of C (Carbon), 0.15-0.40% of Si (Silicon), 0.45-0.70% of Mn (Manganese), no more than 0.020% of P (Phosphorus), no more than 0.005% of S (Sulfur), 0.90-1.10% of Cr (Chromium), 0.45-0.60% of Mo (Molybdenum) and the balance of Fe (Ferrum) and inevitable impurities. The steel plate for the high toughness 15CrMoR pressure container, provided by the invention, has the advantages as follows: (1) as impact toughness of 15CrMoR is high, low temperature impact performance is that transverse impact is not less than 80 J at -40 DEG C and far higher than the nationally specified transverse impact; (2) pure steel quality and low content of harmful elements such as S and the like; (3) as refined grain elements, such as Nb, V, Ti and the like, are not added, cost is greatly saved; and (4) when a requirement on low temperature toughness is satisfied, good conventional properties and good high-temperature tensile properties are obtained.

Description

technical field [0001] The invention relates to the field of manufacturing chromium-molybdenum series heat-resistant pressure vessel steel, in particular to a high-toughness 15CrMoR steel plate for pressure vessels. [0002] Background technique [0003] 15CrMoR steel is a kind of medium-temperature pressure vessel steel commonly used in petrochemical equipment. Because it works under high temperature and pressure, its service conditions are harsh, so the material is required to have high thermal strength, good toughness and plasticity, and durability. Corrosion and welding properties. [0004] Although most of the 15CrMoR heat-resistant steel pressure vessels work at high temperatures, after the pressure vessels and pipelines are manufactured, they will be subjected to a hydraulic test at room temperature or even in extreme climates with a pressure of 1.25 times the design pressure. Finally, it has to go through the hydraulic test and cold start process. Therefore, the st...

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Problems solved by technology

[0004] Although most of the 15CrMoR heat-resistant steel pressure vessels work at high temperatures, after the pressure vessels and pipelines are manufactured, they will be subjected to a hydraulic test at room temperature or even in extreme climates with a pressure of 1.25 times the design pressure. After that, it has to go through the hydraulic test and cold start process. Therefore, the steel should have a certain resistance to brittle fracture on the basis of ensuring its basic performance.

In addition, the container made of this steel type has been operated at high temperature for a long time, and there is no reliable measure to prevent excessive cooling during shutdown, resulting in thermal fatigue and large temperature difference stress. Therefore, its toughness reserve should also be considered when designing this steel type. Enhanced resistance to deformation and temperature changes

Conventional 15CrMoR container steel is required to meet the requirements of impact toughness ≥ 31J at 20°C in accordance with the provisions of GB713-2008, which is far from meeting the special requirements of some users, which limits the application of this steel to a certain extent.