1. SA738GRb. Production process of steel plate.
Production process: converter smelting - LF refining - VD vacuum degassing - 270mm*2100mm section continuous casting - heating - double stand rolling.
Binding specifications: thickness: 8-106mm, width: 1600-4020mm, length: 6000-17500mm.
Second, sa738grb. Implement the standard.
sa738gr.b Implement the standard ASME, SA738GRb. Steel for nuclear power plant containment.
3. SA738GRbChemical composition.
Fourth, SA738GRb. Application analysis and development.
ASME Code Volume I NE Sub-Volume Provisions: Steel Containment (SA-738 Gr..)b steel) after welding without heat treatment allowable maximum wall thickness of 445 mm。The thickness of the steel plate at the junction between the insert plate of the equipment gate and the steel containment cylinder is 55 mm and 52 mm, and the heat treatment temperature is in the range of 595 620. c, heat treatment when cooling down, 425. When C is above, the rate of cooling of steel plate should be controlled, 425. The cooling rate of the steel plate above c should not be greater than 100 °C h, and the holding time of heat treatment is 2 hours and 10 minutes.
The steel containment of nuclear power plants is an important safety barrier in the reactor building, which can contain radiation from the reactor core in the event of a reactor coolant water loss. At present, the steel containment (or steel lining) of the second-generation or second-generation improved nuclear power plants in China is mostly made of high-quality low-alloy steel and carbon structural steel such as domestic 20HRspan>, French A42 and European standard P265GH SPAN>, but the strength of the above-mentioned steel plate is not high, and the toughness level is low, which cannot meet the requirements of the steel performance of the steel containment used in the third-generation AP1000 and CAP1400 nuclear power plants. To this end, the steel containment design of domestic nuclear power plants adopts SA738GR. produced in accordance with ASME standardsB steel as the manufacturing material of containment, this kind of steel is low-alloy high-strength steel, the welding performance is good, but the steel because of the existence of CR, Mo and other elements, if the welding process is not appropriate in the welding process, there is a risk of embrittlement, thermal strain embrittlement and welding cracks in the heat-affected zone of the welded joint, in order to prevent welding cracks, low-hydrogen electrodes and preheating before welding are usually used.