Numerical Simulation and Mechanical Property of 1cr15ni4mo3n Stainless Steel Efficiently Repaired by Laser Metal Deposition with a Synergistic Improvement Strategy

Abstract

Laser metal deposition (LMD) optimized with the strategy of synergistic improvement of laser power (LP) and powder feed rate (PFR) was employed to repair 1Cr15Ni4Mo3N stainless steel (SS) which is an important widely utilized load-bearing material. Herein, the evolution mechanism of thermal behavior during repair process was exposed by establishing a three-dimensional finite element model (FEM), and the results obtained by comprehensive analysis of the temperature distribution and thermal cycle were in good agreement with the trend of microhardness variation in the deposition area. The growth rates of molten pool depth in the center of the second and third layers were 19.79% and 12.33%, respectively, and this variation denotes that the synergistic increasing rates of LP and PFR is critical for densification of microstructure. Moreover, the average tensile strength and impact toughness of the laser repaired specimen (LS) were derived to be 1489 MPa and 88.7 J/cm2, which are 10.12% and 10.60% higher than that of the base material (BM), respectively. The mechanical property of the LS was guaranteed while the efficiency was improved, indicating that the strategy and the developed FEM can serve to provide application value in rapid maintenance of metal components.

Keywords: Precipitation-hardening stainless steel, Repair efficiency, Laser metal deposition, Finite element analysis, Mechanical property