Evaluation of EV Drive Motor Shaft Produced by Radial Forging: Elemental Mapping Analysis by EPMA

User Benefits

- EPMA elemental analysis makes it possible to evaluate processing technologies and the material strength of hollow shaftsproduced by radial forging. - The elemental distribution that causes fiber flow (metal flow) can be understood. - It is possible to identify material internal defects and evaluate strength improvement by evaluation of the elementaldistribution of inclusions and precipitates.

Introduction

In recent years, the trend toward decarbonization for reduction ofgreenhouse effect gases (GHG) has accelerated. As part of thoseefforts, the shift to electric vehicles (EVs) in the automotive industryis playing a large role in realizing decarbonization. Becauseimprovement of the vehicle cruising range is required forpopularization of EVs, reduction of vehicle body weight has beentaken up as a development theme. In particular, weight reductionof EV drive motor shafts has become an important developmenttheme not simply as a means of extending the cruising range, butalso because improvedmotor response can be expected due to thereduced inertial force. Radial forging is a newforging technology forhollow shafts which makes it possible to form the inner and outerdiameters simultaneously by applying force from the radialdirection of hollow shafts or hollow axis with a hammer (die) whileinserting a core bar into the shaft to transcribe the inner diametershape. Since hollow shafts produced by the radial forging processsatisfy both strength and weight reduction requirements, theseproducts have attracted attention as next-generation shafts. As part of a multi-faceted evaluation of motor shafts produced byradial forging introduced previously in other Application Newsarticles, this article introduces an example of application ofan elemental mapping analysis by the EPMA-8050G electronprobe microanalyzer, focusing on inclusions and fine precipitates.

April 24, 2023 GMT