Strength Differential Effect in Martensitic Stainless Steel Under Quenching and Partitioning Heat Treatment Condition
The quenching and partitioning (Q&P) heat treatment enables a higher formability of high strength martensitic steels. Therefore it is necessary to have some metastable austenite in the microstructure, which transforms in martensite during plastic deformation (transformation induced plasticity - TRIP effect). This microstructure can be achieved by the two-step heat treatment, consisting of quenching in a way, which retains a certain amount of austenite. A subsequent low temperature annealing, the so called partitioning, stabilizes the retained austenite due to carbon diffusion. The Q&P heat treatment was investigated for the martensitic stainless steel 1.4034 (X46Cr13, AISI 420) concerning the influence of varying austenite fractions. In line with these efforts the characterization of the mechanical properties, focusing on the materials behavior under different mechanical load scenarios, were performed. Therefore quasi static tension and compression tests were carried out. Moreover, a comprehensive analysis of the microstructural evolution was performed for different stages of heat treatment, including optical microscopy and electron backscatter diffraction. The comparison of common quenching and tempering with the Q&P heat treatment verifies the extensively enhanced materials strength with good ductility whereat the formability is still acceptable. The microstructural explanation was an higher austenite fraction due to austenite retaining between the martensite laths besides the stabilizing of retained austenite. Further a strength differential effect was observed to be much higher than known for tempered martensite. Our investigations show first results and cannot clearly demonstrate the complex microstructural mechanism. Furthermore we find some interesting differences in the micromechanical behavior compared to the literature with regard to micro-cracking and no TRIP effect under compressive loading.
KeywordsQuenching Partitioning Reversion Martensite Austenite Strength differential effect
Unable to display preview. Download preview PDF.
The authors would like to acknowledge financial support by theGKMM1554 and the MDZWP e.V. Furthermore we like to thank the German Research Foundation and federal state Saxony-Anhalt for large equipment founding.
- Dieck S, Ecke M, Rosemann P, Halle T (2017) Reversed austenite for enhancing ductility of martensitic stainless steel. In: Stebner AP, Olson GB (eds) Proceedings of the International Conference on Martensitic Transformations (Chicago), Springer, Cham, The Minerals, Metals & Materials Series, vol 181, p 012034, https://doi.org/10.1007/978-3-319-76968-4_19CrossRefGoogle Scholar
- Edmonds DV, He K, Rizzo FC, Cooman BCD, Matlock DK, Speer JG (2006) Quenching and partitioning martensite—a novel steel heat treatment. Materials Science and Engineering: A 438-440:25 – 34, https://doi.org/10.1016/j.msea.2006.02.133, proceedings of the International Conference on Martensitic TransformationsCrossRefGoogle Scholar
- Hirth JP, Cohen M (1970) On the strength-differential phenomenon in hardened steel. Metallurgical Transactions 1(1):3–8, https://doi.org/10.1007/bf02819235