Evaluation of EV Drive Motor Shaft by Radial Forging Process

User Benefits

- Fiber flow produced in the forging process can be checked and investigated using hardness and element distributions. - Measurement positions can be selected from the overall view of the test specimen surface, so hardness measurements can be easily performed at target positions. - Element distributions can be obtained from the EPMA in a wide range from large to micro area.

Introduction

Metal is forged by applying impacts or compressing it, which promotes uniformity of the metal microstructure and improves the mechanical properties. The internal microstructure of forged metal also acquires directionality, which is referred to as fiber flow. This is where the mechanical properties are strengthened along the direction of flow. One of the new forging processes is radial forging, where force is applied in the radial direction to a hollow shaft or tube using a hammer (die). Then by inserting a core bar, the internal diameter shape is transferred, and the internal and external surfaces can be formed at the same time. Hollow shafts produced this way are strong and light, so it is attracting attention as the next-generation method of manufacturing shafts. This article introduces an example of the Vickers hardness test using a hardness tester on a cross-section of a forged item. The hardness measurement results were additionally verified by comparing them with the distribution of elements, which were measured using an EPMA electron probe microanalyzer.

May 23, 2023 GMT