Numerical Study on Thermodynamic Behavior during Selective Laser Melting of 24CrNiMo Alloy Steel

Abstract

In this paper, a multi-layer and multi-track finite element model of 24CrNiMo alloy steel by selective laser melting (SLM) is established by using the ABAQUS software. The distribution and evolution of temperature field and stress field and the influence of process parameters on them are systematically studied. The results show that the peak temperature increases from 2153 °C to 3105 °C and the residual stress increases from 335 MPa to 364 MPa with increasing laser power from 200 W to 300 W; the peak temperature decreases from 2905 °C to 2405 °C and the residual stress increases from 327 MPa to 363 MPa with increasing scanning speed from 150 mm/s to 250 mm/s; the peak temperature increases from 2621 °C to 2914 °C and the residual stress decreases from 354 MPa to 300 MPa with increasing preheating temperature from 25 °C to 400 °C. Far away from scanning area, far away from starting point, and the adjacent areas with vertical scanning direction, resulting in a uniform temperature distribution, help to reduce the residual stress. Due to the remelting effect, the interlayer scanning angle changing helps to release the residual stress of the former layer causing a smaller residual stress after redistribution.

Laser Cleaning Combined with Cladding Improves Cladding Quality for Repairing Steel Plates in Pressure Vessels

“…In contrast, Figure 19c shows the cladding layers had rougher cross sections and multiple fold-like tearing edges, indicating a brittle fracture mechanism. At the same laser power, the temperature gradient created in the Inconel 625 powder was less in the LCC specimen than that in the MPLC specimen, which reduced the poles and cracks in the cladding layer [33] and enhanced the impact toughness of the LCC specimen. HAZ of the specimens cut along the Y-direction exhibited a fracture shape significantly different from that of the substrate.…”

Prediction and numerical simulation of residual stress in multi-pass pipe welds

“…There are many methods to measure residual stresses are known as nondestructive, semi-destructive and destructive or diffraction as X-ray diffraction, hole drilling and block removal layering [2]. To reduce the residual stresses effect of welding process quality, research on residual stresses has been a continuous interest among researchers [3][4][5][6][7][8][9][10]. The experimental measurement techniques of residual stresses that involve the complex weld shape or structure, which is very time-consuming and costly.…”