Heat-resisting steel material used as vane or bolt of ultra-supercritical steam turbine and preparation method thereof

Abstract

The invention discloses a heat-resisting steel material used as a vane or a bolt of a steam turbine. The chemical composition of the material (in percentage by weight) is: 0.08 to 0.13 percent of C, 0.35 to 0.65 percent of Mn, 0.30 to 0.70 percent of Ni, 10.0 to 12.0 percent of Cr, 0.10 to 0.4 percent of Mo, 2.5 to 3.5 percent of Co, 2.4 to 3.0 percent of W, 0.15 to 0.25 percent of V, 0.05 to 0.12 percent of Nb, 0.01 to 0.035 percent of N, 0.01 to 0.04 percent of B, and the balance of Fe and impurities. The mechanical property of the heat-resisting steel material is that: in a room temperature tensile test, tensile strength sigma b is more than or equal to 965N/mm<2>; yield strength sigma 0.02 is more than or equal to 689N/mm<2>; tensile stretch delta is more than or equal to 15 percent; percentage of area reduction psi is more than or equal to 45 percent; ballistic work AKv is more than or equal to 10.7J; and hardness HB is less than or equal to 321; in a condition of a high temperature lasting test, temperature is at 660 DEG C, stress is 245N/mm<2>, and crack time T is more than or equal to 100 hours.

Description

technical field [0001] The invention relates to a steam turbine material, in particular to a heat-resistant steel material used as an ultra-supercritical steam turbine blade or bolt and a preparation method thereof. Background technique [0002] With the development of steam turbine manufacturing technology, the capacity of a single unit is getting larger and larger, and steam turbines are developing towards supercritical and ultra-supercritical units. The high-temperature durability of some steam turbine blades and bolt materials can no longer meet the requirements. Contents of the invention [0003] The problem to be solved by the present invention is to provide a heat-resistant steel material used as ultra-supercritical steam turbine blades and bolts, the mechanical properties of which meet the above requirements. [0004] Technical scheme of the present invention is: [0005] A heat-resistant steel for steam turbine blades and bolts, the chemical composition of the h...

AI Technical Summary

Problems solved by technology

[0002] With the development of steam turbine manufacturing technology, the capacity of a single unit is getting larger and larger, and steam turbines are developing towards