Microstructure and Tribological Properties of Laser Forming Repaired 34CrNiMo6 Steel

Abstract

Laser forming repair (LFR) technology has considerable potential in high strength steel structure repair. 34CrNiMo6 steel has been widely used in high-value components, and it is imperative to repair these damaged components. In this study, two different thicknesses of repaired layers are deposited on the 34CrNiMo6 wrought substrate with five layers and 20 layers via LFR technology. The microstructure, phases, microhardness, and tribological properties are analyzed using optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness testing, and dry sliding wear testing. These results show that the 34CrNiMo6 repaired layers were successfully deposited on the substrate. The microstructure of the laser-repaired layers in the five-layer sample included bainite and retained austenite. For the 20-layer sample, the microstructure in the top of the repaired layers was still bainite and retained austenite, whereas that in the bottom of the repaired layers was transformed into ferrite and cementite. The average coefficients of friction of repaired layers is not significantly different from the substrate. The wear rate of the five LFR layers, 20-layer LFR, and substrate samples were 12.89 × 10−6, 15 × 10−6, and 23.87 × 10−6 mm3/N·m, respectively. The laser forming repaired samples had better wear resistance compared to the substrate. The wear mechanism of laser forming repaired samples is abrasive wear; whereas that of the substrate is abrasive wear and fatigue wear.

The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements

“…The possibilities to modify the manufacturing process in the SLM technique has created the possibility to conduct scientific research at many scientific and industry facilities [10,11,12,13,14,15,16,17,18,19]. One of the most common topics is the analysis of the process parameters which influence on the mechanical properties of manufactured elements [20,21,22,23,24,25,26,27,28,29,30]. In this paper, the influence of manufacturing process parameters on the porosity and microhardness of the additive manufactured elements was determined.…”

Microstructure and Mechanical Properties of 34CrNiMo6 Steel Repaired by Friction Stir Processing

“…The XRD patterns are presented in Figure 8, which shows α M (α-Fe in martensite) arising from different hkl planes, with varying intensities. The bainite peaks are attributable to α (110) and α (200) in the SZ and the substrates [7]. The austenite reflections in the substrate sample derived from (111), (200), and (220).…”

“…In addition to the techniques mentioned above, laser forming repair (LFR) has attracted attention in recent years. Huang et al [7,8] repaired 34CrNiMo6 substrates with 34CrNiMo6 powder and investigated the resulting microstructure and tribological properties. Yang et al [9] repaired high-strength steel by LFR and investigated the microstructure and mechanical properties.…”

Experimental Analysis on Bending Behavior of Non‐Alloy Carbon Steel Sheets Using Laser‐Forming Process

“…Their experimental results indicated that the yield and ultimate strengths of laser‐irradiated specimens were enhanced. Huang et al [ 17 ] experimentally investigated performance parameters of laser forming of 34CrNiMo6‐alloyed steel. Kotobi et al [ 18 ] studied the effects of laser beam parameters on the bend angle and residual stresses of St–Ti bimetal.…”