Two-layer laser clad coating as a replacement for chrome electroplating on forged steel
Two-layer laser clad coating as a replacement for chrome electroplating on forged steel
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DOI：
10.1177/09544062211010853
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发表时间：
2021-05-17
影响因子：
2
通讯作者：
Lewis, Roger
中科院分区：
文献类型：
--
作者：
Christoforou, Peter;Dowding, Robert;Lewis, Roger
Chrome电镀是用于耐腐蚀的许多表面工程技术之一，以及在承载应用中防止表面损坏的保护涂层，其表面硬度在1000 Hv的范围内。激光熔覆是一种替代的表面硬化技术，通常用于耐腐蚀性和通过厚的熔覆涂层增加部件的表面硬度。应用Chrome电镀和其他类似的表面工程技术来获得厚涂层可能是低效的，并且成本高，具有实际的工艺限制。本案例研究的目的是研究用镍基碳化钨（Ni-WC）复合层和Inconel 625中间层替换锻钢制成的棒磨机小齿轮的Chrome层的可行性。使用显微硬度和纳米压痕技术获得的机械性能。对小齿轮样品的试样进行三点弯曲试验，以观察裂纹扩展阻力，由于小齿轮样品的弯曲几何形状以及现有涂层和拟定涂层之间的厚度差异，这是一项具有挑战性的任务。裂纹发展被捕获，并与使用数字图像相关（DIC）的塑性变形进行量化。在弯曲中，发现复合涂层Inconel 625和钢基底之间的结合提供了改善的轴向裂纹扩展阻力，其中复合涂层可以承受比Chrome电镀两倍以上的弯曲工具位移。
Chrome plating is one of many surface engineering techniques used for corrosion resistance, as well as a protective coating against surface damage in load bearing applications, with surface hardness in the region of 1000 Hv. Laser cladding is an alternative hardfacing technique often chosen for corrosion resistance and for increasing the surface hardness of components, through thick clad coatings. The application of chrome plating and other similar surface engineering techniques for thick coatings can be inefficient and costly with practical process limitations. The objective of this case study was to investigate the feasibility of replacing the chrome plated layer of a rod mill pinion, made of forged steel, with a Nickel-based Tungsten-Carbide (Ni-WC) composite layer and an intermediate layer of Inconel 625. Mechanical properties were obtained using microhardness and nanoindentation techniques. Three-point bend tests were performed on test specimens from a pinion sample, in order to observe crack propagation resistance, a challenging task due to the curved geometry of the pinion sample and the difference in thickness between the existing and proposed coating layers. Crack development was captured, and plastic deformation was quantified with the use of Digital Image Correlation (DIC). In bending it was found that the bond between the composite coating, Inconel 625 and the steel substrate provided improved resistance to axial crack propagation, where the composite coating could withstand more than twice the bending tool displacement than the chrome electroplating.