Real-time structural analysis of quenching and partitioning (Q&P) in an experimental martensitic steel

•We present an innovative method of studying the Q&P heat treatment process.•A specially engineered steel was used to study carbon partitioning in real-time.•Measurements were obtained using a neutron diffractometer with an in situ furnace.•Real-time evidence of partitioning was observed in the...

Full description

Saved in:
Bibliographic Details
Published in:Journal of alloys and compounds 2013-11, Vol.577, p.S695-S698
Main Authors: Bigg, Timothy D., Edmonds, David V., Eardley, Edwin S.
Format: Article
Language:English
Subjects:
Metals and alloys
Microstructure
Neutron diffraction
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•We present an innovative method of studying the Q&P heat treatment process.•A specially engineered steel was used to study carbon partitioning in real-time.•Measurements were obtained using a neutron diffractometer with an in situ furnace.•Real-time evidence of partitioning was observed in the form of lattice dilatation.•Carbon ‘trapping’ is hypothesised to reduce the carbon available for partitioning. Quenching and Partitioning (Q&P) is a new concept in martensitic steel heat treatment which, as well as other opportunities, offers potential for expansion of the elongation versus strength envelope available to steel users, especially the automotive industry. The Q&P steel concept shares similarities with TRIP steel in that both promote multiphase microstructures of stabilised retained austenite and a harder phase of bainite (TRIP) or martensite (Q&P), although in Q&P the two stages of martensite formation and austenite stabilisation by carbon partitioning are separated. The procedure also provides for both protection and temper strengthening of the martensite fraction. However, confirmatory study of reaction mechanisms has been frustrated by the elevated temperatures required to date to apply Q&P heat treatment to commercial steel compositions. Consequently, a model alloy has been used to separate the various stages of the Q&P heat treatment process, thus allowing diffraction experiments, particularly real-time in situ neutron diffractometry, to measure lattice parameter, lattice strain and phase fraction in order to deduce the concentration and distribution of carbon at different stages during the Q&P treatment.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2013.01.205