Deep cryogenic treatment in AISI D2 tool steel punches to enhance tool life

Fabiano Dornelles Ramos,Josué De Oliveira Bairros,Mauro Francisco Castro Moscoso

doi:10.4322/2176-1523.20212442

Fabiano Dornelles Ramos, Josué De Oliveira Bairros + Show 1 more

Open Access

https://doi.org/10.4322/2176-1523.20212442

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Abstract

New materials and heat treatment are being developed worldwide to improve tool life. Tool steels are expensive due to the alloying elements and fabrication costs. Therefore, the maximization of tool life keeping good surface finishing is especially important to keep the processes attractiveness. The application of cryogenic treatment is promising to enhance mechanical and metallurgical properties of cold work tool steel parts. The possibility of increasing the finer secondary carbides content and decreasing amount of retained austenite during deep cryogenic treatment (DCT) is also an important matter for industry. The aim of this work is to improve tool life by applying DCT in AISI D2 cutting punches and compare these results with punches treated by conventional heat treatment (CHT), vacuum furnace quenching plus triple tempering. The tests used for analyses were: metallography, X-ray diffraction, carbides fraction, hardness and number of parts produced by each punch (practical test). The results indicate that the DCT punches have an enhancement of approximately 50% in its useful life.

Highlights

IntroductionHigh alloying content may provide excellent hardenability and good dimensional stability [6] since the parts are suitable to air quenching
The need to increase productivity without raising production costs leads some sectors of the industry to look for ways to address these needs
Metallographic examination shows the presence of tempered martensite [matrix], primary carbides (PC) and secondary carbides (SC)

Summary

Introduction

High alloying content may provide excellent hardenability and good dimensional stability [6] since the parts are suitable to air quenching. This grade of steel is widely used for cold working, especially for cutting tools and dies production [7, 8]. Since this tool steel has greater alloying elements content, some amount of retained austenite can be formed [9], depending on the heat treatment performed [10]. A cryogenic treatment is recommended by the steel producers to reduce the amount of retained austenite in high carbon steels [11,12,13]

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