Journal ArticleDOI
Effect of normalization and tempering on microstructure and mechanical properties of V-groove and narrow-groove P91 pipe weldments
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In this article, the effect of post weld heat treatment and normalized and tempered (N&T) heat treatment on tensile properties and hardness variation of P91 weldments was investigated.Abstract:
In Very High Temperature Reactor (VHTR), The Nb-V modified 9Cr-1Mo (P91) creep strength enhanced ferritic (CSEF) steel is currently considered as a candidate material for reactor internals and reactor pressure vessels (RPVs). After the welding of P91 steel, the inhomogeneous microstructure of weldment is a serious issue because it promotes the well-known Type IV cracking in P91 weldments. The present research work is focused on how the microstructure evolve in various zone of P91 pipe weldment during the sub-critical post weld heat treatment (PWHT) and normalized and tempered (N&T) heat treatment. The effect of PWHT and N&T heat treatment are also considered on tensile properties and hardness variation of P91 weldments. To characterize the sample scanning electron microscope (SEM), X-ray diffraction (XRD) and optical micrograph was used. It was observed that the N&T heat treatment provides the homogeneous microstructure compared to PWHT. The superior mechanical properties was also measured in N&T condition compared to PWHT. Study of fracture surface morphology of tensile tested specimen in different heat treatment condition is also presented.read more
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Journal ArticleDOI
Some studies on P91 steel and their weldments
TL;DR: In this article, microstructure evolution in P91 steel and their weldments are reviewed in as-virgin and heat treatment and creep exposure condition, and the role of grain coarsening, Cr/Fe ratio, lath widening and dislocation density on creep rupture life of base metal and weldments is discussed.
Journal ArticleDOI
Microstructure and mechanical property relationship for different heat treatment and hydrogen level in multi-pass welded P91 steel joint
TL;DR: In this paper, the effect of heat treatment condition and diffusible hydrogen level on microstructure and mechanical properties of multi-pass shielded metal arc welded (SMAW) P91 steel butt joints of 18mm thickness has been studied.
Journal ArticleDOI
Role of evolving microstructure on the mechanical behaviour of P92 steel welded joint in as-welded and post weld heat treated state
TL;DR: In this article, an autogenous gas tungsten arc welded P92 weld joint was subjected to two different post weld heat treatment (PWHT) procedures, which reduced the heterogeneity gradient along the weld cross section.
Journal ArticleDOI
Homogenization of P91 weldments using varying normalizing and tempering treatment
TL;DR: In this article, the effect of varying heat treatment on tensile properties and hardness of P91 pipe weldments were studied for V-groove and narrowgroove weld designs.
Journal ArticleDOI
Creep properties, creep deformation behavior, and microstructural evolution of 9Cr-3W-3Co-1CuVNbB martensite ferritic steel
TL;DR: In this paper, the relationship between minimum creep rate and applied stress followed the Bird-Mukherjee-Dorn (BMD) equation, and the modified BMD equation was proposed using threshold stress to elucidate the actual creep deformation mechanism.
References
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Journal ArticleDOI
Structural materials for Gen-IV nuclear reactors: Challenges and opportunities
TL;DR: This paper presents a summary of various Gen-IV reactor concepts, with emphasis on the structural materials issues depending on the specific application areas, and demonstrates that novel alloy and microstructural design approaches coupled with new materials processing and fabrication techniques may mitigate the challenges.
Journal ArticleDOI
Elevated temperature ferritic and martensitic steels and their application to future nuclear reactors
TL;DR: In the 1970s, high chromium (9-12%Cr) ferritic/martensitic steels became candidates for elevated temperature applications in the core of fast reactors.
Journal ArticleDOI
The evolution of dislocation density during heat treatment and creep of tempered martensite ferritic steels
TL;DR: In this article, the evolution of dislocation density in two tempered martensite ferritic steels (a 12% and a 9% chromium steel, X20 and P91) during heat treatment and creep is analyzed using transmission electron microscopy (TEM) and X-ray diffraction (XRD); both methods yield results which are in good agreement when rationalizing the XRD-data based on densities of free dislocations.
Journal ArticleDOI
Type IV cracking in ferritic power plant steels
TL;DR: In this paper, the authors assess the relationship between the composition and microstructure of 9-12 Cr steels, the welding and fabrication procedures and how these factors translate into a propensity for type IV failures.
Book ChapterDOI
Creep-resistant Steels
TL;DR: The development of creep-resistant steels has been discussed in this article, where the authors present a detailed description of the deformation and deformation mechanism map of creep deformation in steel.