In situ synchrotron diffraction studies on the temperature-dependent plane-specific elastic constants in a high-strength quenched and tempered structural steel

2013 ◽  
Vol 69 (2) ◽  
pp. 187-190 ◽  
Author(s):  
R.K. Dutta ◽  
R.M. Huizenga ◽  
M. Amirthalingam ◽  
A. King ◽  
H. Gao ◽  
...  
2014 ◽  
Vol 777 ◽  
pp. 231-236
Author(s):  
R.K. Dutta ◽  
R.M. Huizenga ◽  
M. Amirthalingam ◽  
H. Gao ◽  
A. King ◽  
...  

In-situ phase transformation behaviour of a high strength (830 MPa yield stress) quenched and tempered S690QL1 (Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt. %)) structural steel, during continuous cooling under different mechanical loading conditions to promote the bainitic transformation, was studied. Time-temperature-load resolved 2D synchrotron diffraction patterns were recorded and used to calculate the transformation strains. The temperature dependent elastic constants of ferrite in the steel were also determined using \textit{in-situ} tensile tests at different temperatures in a synchrotron X-ray diffractometer. The transformation strains were calculated under different loading conditions.The elastic constants were calculated from the lattice parameters at 25 °C, 200 °C, 300 °C, 400 °C, 500 °C and 600 °C. The elastic constants varied from 202 GPa at 25 °C to 143 GPa at 600 °C. The variation in lattice plane strains during phase transformation under small external loads were calculated. Bulk measurement techniques such as dilatation experiments give the averaged transformation strains. However, in-situ synchrotron measurements performed in this work describe the transformation strains of the individual transforming phases and the strains arising due to possible variant selection.


2014 ◽  
Vol 922 ◽  
pp. 126-131 ◽  
Author(s):  
R.K. Dutta ◽  
R.M. Huizenga ◽  
M. Amirthalingam ◽  
H. Gao ◽  
A. King ◽  
...  

The effect of plastic deformation of austenite at elevated temperatures on the kinetics ofphase transformations during continuous cooling was studied in a high strength quenched and tem-pered structural steel S690QL1 (Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt.%)) by means of in-situsynchrotron diffraction. The steel was heated to 900 C (above Ac3) in the austenite region and elon-gated by 6% followed by quenching to room temperature. Time-temperature-load resolved 2D syn-chrotron diffraction patterns were recorded and used to calculate the local d-spacings between latticeplanes. The plane specific diffraction elastic constants of austenite at 900 C in the steel were deter-mined from the local d-spacings. The effect of the deformation of austenite on the phase transforma-tion kinetics was studied. The evolution of lattice parameters and the phase fraction of the bcc phasesduring the quenching process were calculated.The calculated plane specific elastic constants of austenite at 900 C varied between 32 GPa to140 GPa for the different fhklg reflections of austenite. The deformation of austenite at 900 C re-sulted in the formation of a mixture of 38 % bainite, 59 % martensite and 3 % retained austenite afterquenching to room temperature. Without hot deformation, austenite transformed to 9 % bainite and88 % martensite with 3 % retained austenite. The presence of the bainitic and the martensitic phaseswas observed fromthe change in the slopes of the lattice parameters of the bcc phase during quenchingand confirmed by microscopy.


Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2378
Author(s):  
Dominik Kiefer ◽  
Jens Gibmeier ◽  
Andreas Stark

In situ dilatometry experiments using high energy synchrotron X-ray diffraction in transmission mode were carried out at the high energy material science beamline P07@PETRAIII at DESY (Deutsches Elektronen Synchrotron) for the tempering steel AISI 4140 at defined mechanical loading. The focus of this study was on the initial tempering state ( f e r r i t e ) and the hardened state ( m a r t e n s i t e ). Lattice strains were calculated from the 2D diffraction data for different h k l planes and from those temperature-dependent lattice plane specific diffraction elastic constants ( D E C s ) were determined. The resulting coupling terms allow for precise stress analysis for typical hypoeutectoid steels using diffraction data during heat treatment processes, that is, for in situ diffraction studies during thermal exposure. In addition, by averaging h k l specific Y o u n g ′ s m o d u l i and P o i s s o n r a t i o s macroscopic temperature-dependent elastic constants were determined. In conclusion a novel approach for the determination of phase-specific temperature-dependent DECs was suggested using diffraction based dilatometry that provides more reliable data in comparison to conventional experimental procedures. Moreover, the averaging of lattice plane specific results from in situ diffraction analysis supply robust temperature-dependent macroscopic elastic constants for martensite and ferrite as input data for heat treatment process simulations.


Author(s):  
R-R. Lee

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.


Alloy Digest ◽  
2017 ◽  
Vol 66 (2) ◽  

Abstract Strenx 700 is a high-strength structural steel with a minimum yield strength of 650–700 MPa (94–102 ksi) depending on thickness. Strenx 700 meets the requirements of EN 10 025-6 for the S690 grade and thicknesses. Typical applications include demanding load-bearing structures. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, machining, and joining. Filing Code: SA-779. Producer or source: SSAB Swedish Steel Inc..


Alloy Digest ◽  
2012 ◽  
Vol 61 (5) ◽  

Abstract Dillimax 550 is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of 690 MPa (100 ksi). Plate is delivered in three qualities: basic, tough, and extra tough. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-652. Producer or source: Dillinger Hütte GTS.


Alloy Digest ◽  
2012 ◽  
Vol 61 (3) ◽  

Abstract Dillimax 500 is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of 500 MPa (72 ksi). Plate is delivered in three qualities: basic, high toughness, and extra tough. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, heat treating, and joining. Filing Code: SA-645. Producer or source: Dillinger Hütte GTS.


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