A STUDY ON THE FATIGUE RELIABILITY OF THERMALLY SPRAIED MATERIAL

热喷涂材料疲劳可靠性研究

基本信息

批准号：
07405008
负责人：
SHIMIZU Masao
金额：
$ 6.4万
依托单位：
KEIO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07405008/
关键词：
FATIGUE SURFACE MODIFICATION THERMAL SPRAYING FUSING POROSITY 再溶融処理溶射 Co基自溶合金疲労信頼性

项目摘要

Since a thermally sprayd coating has high wear, corrosion and heat resisance, it is used in many engineering fields for surface reinforcement and for repair of machine parts such as paper mill rolls, shafts and large bearings. With an increasing demand for the application of this process in several industries, it has become important to clarify the fatigue resistance of thermally sprayd steel. However, many problems remain unsolved concerning the fatigue properties of thermally sprayd coatings.In this study, the characteristics of the fatigue life of a thermally sprayd specimen with Co-based self-fluxing alloy were examined. The effects of the interface conditions on the sprayd specimen's fatigue strength were also studied. Rotational-bending fatigue tests were carried out to clarify the effect of post heat treatment (fusing treatment) on the fatigue strength of a sprayd specimen. The fatigue fracture mechanisms of thermally sprayd specimens were also examined using a Scanning Electron … More Microscope.The rusults are summarized as follows :(1) Fusing treatment temperature, heating rate and holding time strongly affect the characteristics of sprayd coatings such as configuration of microstructure, hardness and volume fraction of micro-pore (porosity).(2) Adhesion strength of thermally sprayd specimens which are fused by using a induction heating system is governed by mechanical interaction. Howver, in the case of a sprayd specimen fused by using a vacuum furnace, the diffusion of chemical elements strongly affects the characteristics of interface and adhesion strength.(3) There is considerable scatter in the value of porosity for torch-fused specimens. However, it is possible to achieve high quality coatings through well controlled fusing by using an induction heating system. In this case, the scatter of fatigue lives is much smaller than that of a torch-fused specimen.(4) The fatigue fracture mechanisms of thermally sprayd specimens are described as follows : (i) a crack start at the point of interface, (ii) the crack growth to the substrate (iii) the crack spreads from the interface in the sprayd coating and the entire coating fails rapidly (iv) the remaining part of substrate fails as a result of the coating failure. Less

由于热喷涂涂层具有较高的磨损，腐蚀和热弹性，因此在许多工程领域中都用于表面加固，并用于修复机器零件，例如造纸厂卷，轴和大轴承。随着对该过程在多个行业中应用的需求不断增长，阐明热喷涂钢的疲劳性抗性已变得很重要。然而，关于热喷涂涂层的疲劳特性，许多问题仍然无法解决。在这项研究中，检查了带有基于CO的基于CO的自输液合金的热喷涂样品的疲劳寿命的特征。还研究了界面条件对喷雾标本疲劳强度的影响。进行了旋转弯曲疲劳测试，以阐明热处理后（融合处理）对喷雾标本的疲劳强度的影响。 The fatigue fracture mechanisms of thermally sprayed specimens were also examined using a Scanning Electron … More Microscope.The rusults are summarized as follows:(1) Fusing treatment temperature, heating rate and holding time strongly affect the characteristics of spray coatings such as configuration of microstructure, hardness and volume fraction of micro-pore (porosity).(2) Adhesion strength of thermally spray specimens which are fused by使用诱导的加热系统受机械相互作用的控制。霍弗（Howver），如果使用真空炉融合的喷雾样品，化学元件的扩散会强烈影响界面和粘合强度的特性。（3）孔子粉状样品的孔隙率值有相当大的散射。但是，可以通过使用感应加热系统通过良好的控制融合来实现高质量的涂料。 In this case, the scatter of fatigue lives is much smaller than that of a torch-fused specimen.(4) The fatigue fracture mechanisms of thermally sprayed specimens are described as follows: (i) a crack start at the point of interface, (ii) the crack growth to the substrate (iii) the crack spreads from the interface in the spray coating and the entire coating fails rapidly (iv) the remaining part of substrate fails as涂层故障的结果。