630 DEG C heat-resistant steel and smelting method thereof

Abstract

The invention relates to 630 DEG C heat-resistant steel and a smelting method thereof, and belongs to the technical field of molten metal smelting. The steel and the method are used for solving the problem that heat-resistant steel is difficult to smelt. The 630 DEG C heat-resistant steel comprises the following chemical components in percentage by mass: 0.06%-0.1% of C, 0.2%-0.4% of Si, 0.4%-0.6% of Mn, 8%-10% of Cr, 2.5%-3.5% of W, 2.5%-3.5% of Co, 0.18%-0.25% of V, 0.01%-0.02% of B, 0.006%-0.01% of N, 0.04%-0.06% of Nb and the balance of Fe. The smelting method of the 630 DEG C heat-resistant steel adopts an EAF + LF + VOD + LF smelting process flow. By implementing the technical scheme, the 630 DEG C heat-resistant steel is obtained, the content of Cr in the heat-resistant steel is 8%-10%, the content of C is 0.06%-0.1%, and the heat-resistant steel contains W and Co with high content, so that a steel casting cast by the heat-resistant steel has higher heat resistance and high-temperature durability.

Description

technical field [0001] The invention relates to the technical field of cast steel smelting, in particular to a method for smelting heat-resistant steel. Background technique [0002] Increasing the intake air temperature can significantly improve the efficiency of the steam turbine generator set and reduce harmful gas emissions. Therefore, domestic and foreign steam turbine manufacturers are working hard to increase the steam temperature of their units. The steam temperature of ultra-supercritical steam turbines that have been put into commercial operation has reached 620°C, and domestic and foreign manufacturers are developing ultra-supercritical steam turbines with temperatures ranging from 630°C to 650°C or even higher. Turbine. 9%~12%Cr ferritic heat-resistant steel has excellent mechanical properties and physical properties, and is very suitable for manufacturing high-temperature rotors of steam turbines. In order to meet the material requirements of 650°C, Japanese ex...

AI Technical Summary

Problems solved by technology

[0003] In view of the above problems of difficult smelting of 630°C heat-resistant steel and low success rate, it is necessary to propose a smelting method of 630°C heat-resistant steel. The 630°C heat-resistant steel not only has high content of W, Co and other elements, but also requires B, N elements, the smelting method overcomes the influence of the recovery rate of W, Co, B and other elements, and breaks through the technical bottleneck of smelting 630°C heat-resistant steel