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Pearlite
About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.
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TL;DR: In this paper, the effects of V and Mo addition on tensile and Charpy impact properties of API X70 linepipe steels were investigated. And the tensile test results indicated that the increase in tensile strength was achieved only when Mo was added to the high-V alloy, while the yield strength did not vary much in these specimens except the water-cooled specimens.
Abstract: This study is concerned with the effects of V and Mo addition on tensile and Charpy impact properties of API X70 linepipe steels. Twelve kinds of steel specimens were produced by varying V and Mo additions and rolling conditions. The addition of V and Mo promoted the formation of acicular ferrite (AF), banitic ferrite (BF), and martensite-austenite (MA) constituents, while suppressing the formation of polygonal ferrite (PF) or pearlite (P). The tensile test results indicated that the tensile strength of the specimens rolled in the two-phase region increased with the addition of V and Mo, while the yield strength did not vary much in these specimens except the water-cooled specimens, which showed the increased yield strength with addition of Mo. The tensile strength of specimens rolled in the single-phase region followed by water cooling increased with increasing V and Mo contents. The yield strength, however, did not vary much with increasing V content or with addition of Mo to the low-V alloy. In these specimens, a substantial increase in the strengths was achieved only when Mo was added to the high-V alloy. The specimens rolled in the single-phase region had higher upper-shelf energy (USE) and lower ductile-brittle transition temperature (DBTT) than the specimens rolled in the two-phase region, because their microstructures were composed of AF and fine PF. According to the electron backscatter diffraction (EBSD) analysis data, the effective grain size in AF was determined by crystallographic packets composed of a few fine grains having similar orientations. Thus, the decreased DBTT in the specimens rolled in the single-phase region could be explained by the decrease in the overall effective grain size due to the presence of AF having smaller effective grain size.
62 citations
23 Jun 2014-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a microalloyed steel heavy plate was subjected to two-stage controlled rolling and continuous cooling to explore the microstructure and mechanical properties in the plate.
Abstract: A microalloyed steel heavy plate was subjected to two-stage controlled rolling and two-stage continuous cooling to explore the microstructure and mechanical properties in the plate. The objective was to obtain superior mechanical properties in the plate by exploiting the advantage of microalloyed precipitates in stimulating intragranular ferrite nucleation. Yield strength, tensile strength, and percentage of elongation of 550 MPa, 655 MPa, and 26.5% were obtained at quarter-thickness and 515 MPa, 645 MPa, and 29.5% at mid-thickness. The impact energy determined at −40 °C was ~93 J and 71 J for quarter-thickness and mid-thickness regions, respectively. The microstructure consisted of polygonal ferrite, acicular ferrite, and pearlite. Microalloyed precipitates provided effective nucleation sites for intragranular ferrite and ensured near-homogenous microstructure and mechanical properties in the heavy steel plate.
62 citations
TL;DR: In this article, the impact toughness of microalloyed steels has been investigated and the effect of temperature on splitting has been discussed, and the impact and fracture toughness of the steel has been calculated for all temperatures and correlated with impact toughness.
61 citations
TL;DR: In this article, the micromechanisms of cleavage fracture under notched-bend conditions for fully pearlitic microstructures are compared to those exhibited by simple ferrite-carbide micro structures and are shown to exhibit substantial differences to those of the simple micro structures.
61 citations
TL;DR: The spheroidization of cementite in 0.74% carbon steel during annealing at 700°C has been investigated for three different interlamellar spacings by optical and scanning electron microscopy.
61 citations