9%Cr钢表面激光熔覆1CrMo合金层的力学性能研究

Study on Mechanical Properties of 1CrMo Layer Deposited by Laser Cladding on 9%Cr Steel Surface

为了解决9%Cr钢汽轮机转子轴颈堆焊1CrMo合金时,由于稀释率大、热输入高导致的新转子轴径表面降Cr质量分数效率低和磨损后不适合局部修复的问题,采用激光熔覆技术替代堆焊,在9%Cr钢表面进行了1CrMo合金激光熔覆试验,并对熔覆层组织结构和性能进行了测试分析。结果表明:激光熔覆技术可在9%Cr钢表面制备成形质量及力学性能良好的1CrMo合金熔覆层,熔覆层组织主要由铁素体和颗粒状碳化物组成;与堆焊相比,激光熔覆可有效降低基体对熔覆层的稀释率,提高表面降Cr质量分数效率;与基体材料相比,1CrMo合金熔覆层强度略低,但塑韧性更好,力学性能达到9%Cr钢汽轮机转子轴颈设计要求。

To solve the problem of low Cr reduction efficiency on the journal surface of a 9%Cr steel rotor caused by high dilution rate and high heat input when surfacing 1 CrMo alloy on the rotor journal,where local repair is not available after wear damage,a deposit welding test was carried out with 1 CrMo alloy on the surface of 9%Cr steel by laser cladding instead of surfacing,following which,the microstructure and properties of the 1 CrMo cladding layer were tested and analyzed.Results show that the laser cladding technology helps to form good cladding of 1 CrMo alloy on the surface of 9%Cr steel,with high mechanical properties of the cladding layer.Compared with surfacing technology,the laser cladding can effectively reduce the dilution of substrate to the cladding layer,thus improving the Cr reduction efficiency of the surface.Compared with the base metal,the tensile strength of 1 CrMo cladding is slightly lower,but its ductility and toughness are better,proving the mechanical properties of 1 CrMo cladding to meet the design requirements of 9%Cr rotor journal in steam turbines.