Steel with good high temperature property and thick specification for nuclear power safety injection box and manufacturing method thereof

Abstract

The invention discloses steel with a good high temperature property and a thick specification for a nuclear power safety injection box and a manufacturing method thereof. The steel comprises 0.14-0.20% of C, 0.10-0.60% of Si, 0.30-0.40% of Mn, at most 0.008% of P, at most 0.002% of S, 0.30-0.60% of Mo, 0.45-0.90% of Ni, 0.50-0.80% of Cr, at most 0.05% of Cu, at most 0.04% of Al, at most 0.00015% of H, at most 0.0020% of O and the rest Fe and unavoidable impurities. A steel ingot is heated to 1150-1350 DEG C, the holding time is larger than 2h, the compression ratio of a steel plate is larger than 3 to 1, the initial rolling temperature is at least 1100 DEG C, the finish rolling temperature is at least 920 DEG C, and the rolling speed is 1.0-1.5m / s. The quenching temperature is 850-925 DEGC, and the holding time is 1-4min / mm. The tempering temperature is 630-670 DEG C, and the holding time is 3-7min / mm. After the steel plate with a thick specification of 80-150mm is subjected to heat treatment after quenched-tempered heat treatment and 16 hours of simulated welding, the comprehensive mechanical property is good.

Description

technical field [0001] The invention belongs to ferrous metal materials, and in particular relates to a steel for a nuclear power safety injection box with excellent high-temperature tensile properties and a manufacturing method. Background technique [0002] The nuclear power safety injection tank is an advanced equipment that injects cooling water into the accident equipment when an accident occurs in a nuclear power plant. The safety injection tank contains boron-containing water, and the upper cavity is filled with nitrogen. When the pressure of the reactor coolant system drops below the pressure of the safety injection tank , Boron-containing water is injected into the cold section of the reactor coolant system by nitrogen pressure, which can submerge the core in a short time and avoid melting of fuel rods, thereby ensuring the safety and integrity of the reactor system. Its manufacturing requirements are very strict, the process control is extremely harsh, and the acce...

AI Technical Summary

Problems solved by technology

At present, the steel plates for the head of the safety injection box and the cylinder are almost entirely dependent on imports, which are expensive and have a long delivery time

There are mainly two problems in the following aspects: one is that according to the plate design requirements, the head and cylinder plates are ultra-wide plates (plate width 4.5m), so there are strict requirements on the equipment and capabilities of the manufacturing plant; After more than 16 hours of simulated post-weld heat treatment, the strength of the steel plate has dropped significantly, especially the tensile strength of the 150°C high-temperature tensile is lower than the index requirement, but limited by imported steel plates, the index has to be lowered

The above-mentioned patent adopts the electric furnace smelting-forging-heat treatment process, the production rhythm is low, and the production cycle is long, which is not suitable for continuous mass production, and the applicable steel plate thickness range is not specified in the examples

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