Development of micro rotary swaging tools of graded tool steel via co-spray forming

Chengsong Cui,Eric Moumi,Florian Böhmermann,Oltmann Riemer,Bernd Kuhfuss,Alwin Schulz,Y Qin,F Vollertsen,S J Yuan,J Lin,T A Dean

doi:10.1051/matecconf/20152109017

Abstract

In order to meet the requirements of micro rotary swaging, the local properties of the tools should be adjusted properly with respect to abrasive and adhesive wear, compressive strength, and toughness. These properties can be optimally combined by using different materials in specific regions of the tools, with a gradual transition in between to reduce critical stresses at the interface during heat treatment and in the rotary swaging process. In this study, a newly developed co-spray forming process was used to produce graded tool materials in the form of a flat product. The graded deposits were subsequently hot rolled and heat treated to achieve an optimal microstructure and advanced properties. Micro plunge rotary swaging tools with fine geometrical structures were machined from the hot rolled materials. The new forming tools were successfully applied in the micro plunge rotary swaging of wires of stainless steel.

Highlights

The selection of tool materials for micro rotary swaging processes is an important issue
These properties can be optimally combined by using different materials in specific regions of the tools, with a gradual transition in between to reduce critical stresses at the interface during heat treatment and in the rotary swaging process
The varying properties can be optimally combined by using different materials in the specific regions of the tools

Summary

Introduction

The selection of tool materials for micro rotary swaging processes is an important issue. The combination of materials can be achieved by the use of a gradual transition in between to reduce critical stresses at the interface during heat treatment and in the swaging process. Such graded materials have much lower tendency to delaminate than surface-coated materials. A newly developed co-spray forming process is supposed to produce such graded tool materials [4] In this process, two melts of different tool steels are co-sprayed and deposited on a flat substrate, resulting in a graded flat product when the two sprays partially overlap. The graded deposits were subsequently hot rolled and heat treated to achieve optimal microstructure and material properties. Micro plunge rotary swaging tools were machined from the graded steels and tested in the deformation of wires of stainless steel 1.4301 (AISI 304)

Production of tool materials

Machining of micro rotary swaging tools

Micro rotary swaging of steel wires

Summary