Effect of Interlayer Cooling on the Preparation of Ni-Based Coatings on Ductile Iron

Yuyu He,Fei Xie,Jihong Cheng,Jianping Shi,Yijian Liu,Wuyun Huang,Jiquan Yang,Zhaowei Zhu

doi:10.3390/coatings10060544

Abstract

In metal additive manufacturing without interlayer cooling, the macro-size of the layer itself is difficult to control due to the thermal storage effect. The effect of interlayer cooling was studied by cladding Ni-based coatings on the substrate of ductile iron. The results show that under the same process parameters, compared with non-interlayer cooling deposition, the dilution rate is better, and the thickness increase of interlayer cooling deposition is more uniform, which is conducive to controlling the macro-size of the interlayer cooling deposition. Furthermore, interlayer cooling deposition has fewer impurities and more uniform microstructures. Moreover, the average grain size is refined and the dendrite growth is inhibited, which improves the mechanical properties of the coating. Therefore, the hardness of the interlayer cooling specimens is greater than that of the non-interlayer-cooled specimens.

Highlights

Ductile iron possesses the properties of high strength, toughness, wear resistance, shock absorption, easy cutting, notch insensitive, etc
Mughal et al [7,8] used the finite element method to study the process of metal additive manufacturing process
The height of the cladding layers was measured by a micrometer

Summary

Introduction

Ductile iron possesses the properties of high strength, toughness, wear resistance, shock absorption, easy cutting, notch insensitive, etc. It has been proven that continuous deposition without interlayer cooling leads to high and uniform preheating of the substrate, which reduces the deformation of the cladding layer. At the same time, it was found that the continuous multilayer deposition causes a thermal storage effect, which results in the loss of control over dimensional tolerances. As described in the paper, due to the thermal storage during the deposition process, the microstructure of the deposition is uneven This means that as the number of layers increases, the cooling effect becomes worse. Weng et al [11] studied the effects of laser-specific energy on the microstructures and properties of the cladding layers. Cheng et al [13] studied the effects of laser energy density and scanning speed on the properties of the cladding layer. This work can improve the quality of the cladding layer, especially strength and hardness, and help control dimensional tolerances

Experimental Details

Results and Discussion

Energy-dispersive

Conclusion