Overview
![](/assets/images/picto-drapeau-france-3a76576a5d60a512053b4612ab58dae5.png)
ABSTRACT
The goal of this article is to describe the metallurgical mechanisms during the tempering operation of carbonitrided parts with high nitrogen. We are going to present the impact of nitrogen on the stability of residual austenite, the martensite desaturation, the temper resistance… The hardness and the compressive residual stresses profiles after tempering are always higher than the values obtained with case carburizing or standard carbonitriding.
Read this article from a comprehensive knowledge base, updated and supplemented with articles reviewed by scientific committees.
Read the articleAUTHOR
-
Alexandre FLEURENTIN: Judicial expert to the Paris Court of Appeal - METALLO CORNER Conseils, Paris, France
INTRODUCTION
High Nitrogen carbonitriding is characterized by :
– a percentage of surface nitrogen greater than 0.4%,
– a depth of enrichment that can exceed 600 µm,
– residual austenite and nitrogen-rich martensite.
This new thermochemical treatment enables us to meet two closely related technical challenges: downsizing to reduce the weight of on-board parts, and increasing the stresses applied. Both of these issues can lead to a rise in system temperature, degrading the mechanical characteristics of products if the temperature reached exceeds that set for tempering. We will see in this article that this treatment can also be used in the case of duplex PVD (physical vapour deposition) or PACVD (plasma-assisted chemical vapour deposition) treatments, where the substrate can be heated above stress-relieving tempering temperatures.
In the introductory article
– the amount of carbon and nitrogen absorbed,
– addition elements contained in treated steels.
Consequently, the choice of steel, the selection of working atmosphere (carbon potential and nitriding potential) and the depth of grinding are essential criteria for optimizing the fatigue life of mechanical parts using nitrogen-enriched carbonitriding.
The aim of this article on new carbonitrides is to continue the analysis by looking at the metallurgical phenomena that occur when the temperature of a carbonitrided part is raised with more or less absorbed nitrogen: during tempering, during the production of a PVD or PECVD-type coating, or in service, mainly in the case of products subjected to contact fatigue. To illustrate this thinking, it is important to look at the evolution of hardness profiles, residual stresses (estimated by X-ray diffraction (XRD)) and residual austenite content (measured by XRD) for different more or less alloyed, case-hardened or carbonitrided structural steels with different nitriding potentials (Carbo HN and Carbo HN + with KN HN < KN HN + ). These results will enable us to gain a better understanding of nitrogen-enriched...
Exclusive to subscribers. 97% yet to be discovered!
You do not have access to this resource.
Click here to request your free trial access!
Already subscribed? Log in!
![](/assets/images/logo-eti-286623ed91fa802ce039246e516e5852.png)
The Ultimate Scientific and Technical Reference
KEYWORDS
carbonitriding | residual stresses | residual austenite | precipitation hardened
This article is included in
Metal treatments
This offer includes:
Knowledge Base
Updated and enriched with articles validated by our scientific committees
Services
A set of exclusive tools to complement the resources
Practical Path
Operational and didactic, to guarantee the acquisition of transversal skills
Doc & Quiz
Interactive articles with quizzes, for constructive reading
Ageing treatment after nitrogen over-enriched deep carbonitriding
Bibliography
Events
The SVTM trade show for vacuum and materials processing takes place every year in France.
Directory
Manufacturers – Suppliers – Distributors (non-exhaustive list)
Hacer STTS, ZI des Lanches, Rue des Cyprès, 74300 THYEZ
United Process Controls GmbH, Dürnauer Weg 30, 73092 Heiningen, Germany
Process electronic, ZI des Tilleroyes, 20 rue Thomas Edison, 25000 Besançon, France
Organizations – Federations – Associations (non-exhaustive list)
...
Exclusive to subscribers. 97% yet to be discovered!
You do not have access to this resource.
Click here to request your free trial access!
Already subscribed? Log in!
![](/assets/images/logo-eti-286623ed91fa802ce039246e516e5852.png)
The Ultimate Scientific and Technical Reference