“…Due to intermediate cooling the narrow interface region of the tempered martensite rim and ferrite-pearlite core region transforms to bainite. 20–22 1 Images of the cross-section of the a Chinese, b Fe 500D, c Fe 600, d Fe 500 (12 mm), e Fe 500 (16 mm) rebars and f schematic diagram of the cross-section and its different zones of TMT rebar…”
Section: Resultsmentioning
confidence: 99%
“…Due to intermediate cooling the narrow interface region of the tempered martensite rim and ferrite-pearlite core region transforms to bainite. [20][21][22] In all types of samples the measured tempered martensite rings are about 1.0-1.6 mm ( Table 2). Figures 2-4 show three distinctive regions where the outer region comprises tempered martensite, the transition zone has narrow bainitic structure and the core zone consists of polygonal, non-polygonal ferrite of white contrast and pearlite of dark contrast.…”
The present work aims to study the evaluation of the microstructure, tensile properties, hardness, corrosion behaviour of the various grades of rebars. The microstructures of all rebar samples comprise an outer tempered martensite ring with an inner core of ferrite-pearlite in between a narrow bainitic transition zone. Maximum hardness is achieved at the periphery which gradually decreases towards the centre. Chinese grade has a similarity with the Fe 600 rebar in terms of strength and % elongation, whereas Fe 500D and Fe 500 have lower strength but higher ductility. The EDS analyses of corrosion products obtained after immersion test in 5% NaCl solution for a period of 7 days apparently indicate the occurrences of iron oxy-hydroxides and iron oxides. X-ray diffraction and FTIR studies of the corrosion products formed on all thermomechanically treated (TMT) rebar surfaces after the aforesaid immersion test primarily indicate the presence of Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Magnetite (Fe 3 O 4 ) and Maghemite (γ-Fe 2 O 3 ). Fe 500 (12 mm) and Chinese rebars have lower corrosion resistance as compared to the other rebars in 5% NaCl solution. Nevertheless, all the TMT rebars are corrosion resistant and can be satisfactorily used for construction purposes.
“…Due to intermediate cooling the narrow interface region of the tempered martensite rim and ferrite-pearlite core region transforms to bainite. 20–22 1 Images of the cross-section of the a Chinese, b Fe 500D, c Fe 600, d Fe 500 (12 mm), e Fe 500 (16 mm) rebars and f schematic diagram of the cross-section and its different zones of TMT rebar…”
Section: Resultsmentioning
confidence: 99%
“…Due to intermediate cooling the narrow interface region of the tempered martensite rim and ferrite-pearlite core region transforms to bainite. [20][21][22] In all types of samples the measured tempered martensite rings are about 1.0-1.6 mm ( Table 2). Figures 2-4 show three distinctive regions where the outer region comprises tempered martensite, the transition zone has narrow bainitic structure and the core zone consists of polygonal, non-polygonal ferrite of white contrast and pearlite of dark contrast.…”
The present work aims to study the evaluation of the microstructure, tensile properties, hardness, corrosion behaviour of the various grades of rebars. The microstructures of all rebar samples comprise an outer tempered martensite ring with an inner core of ferrite-pearlite in between a narrow bainitic transition zone. Maximum hardness is achieved at the periphery which gradually decreases towards the centre. Chinese grade has a similarity with the Fe 600 rebar in terms of strength and % elongation, whereas Fe 500D and Fe 500 have lower strength but higher ductility. The EDS analyses of corrosion products obtained after immersion test in 5% NaCl solution for a period of 7 days apparently indicate the occurrences of iron oxy-hydroxides and iron oxides. X-ray diffraction and FTIR studies of the corrosion products formed on all thermomechanically treated (TMT) rebar surfaces after the aforesaid immersion test primarily indicate the presence of Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Magnetite (Fe 3 O 4 ) and Maghemite (γ-Fe 2 O 3 ). Fe 500 (12 mm) and Chinese rebars have lower corrosion resistance as compared to the other rebars in 5% NaCl solution. Nevertheless, all the TMT rebars are corrosion resistant and can be satisfactorily used for construction purposes.
“…TMT ( Thermo-mechanical treated) rebar is the time proven match for reinforcing concrete structures on accounts of similarity in thermal expansion, ability to bond well with concrete and, above all, the ability to shoulder most of the tensile stress acting on the structure [1]. TMT bars means Thermo Mechanically Treated Bars made from medium carbon steel (Carbon 0.25 Max Wt.…”
Section: Introductionmentioning
confidence: 99%
“…%) and are used in construction industry. Because of its corrosion and rust resistance features it is widely used in construction of buildings in humid areas as well as long lasting, high strength, quality construction [1]. Rebars are "hot rolled" from steel billets and subjected to on-line thermo-mechanical treatment in three successive stages:…”
TMT bars means Thermo Mechanically Treated Bars made from medium carbon steel (Carbon 0.25 Max Wt. %) and are used in construction industry. Because of its corrosion and rust resistance features it is widely used in construction of buildings in humid areas as well as long lasting, high strength, quality construction. Quality aspects of these rebar's are of significance as any inherent abnormality in the material could lead to unwanted productivity losses or quality claims. In this present study, rebar samples failed during bending operation were collected from construction end for understanding their quality aspect and potential causes of failure while bending. Visual observations of rebar sample (U-bend) longitudinal surface defects were observed in both the tension and compression zone. On appearance, metal folded over the rebar surfaces at an angle. Detailed microstructural investigation revealed that scale entrapment in defects. The above observations indicated that the defect was of lap type and which was generated during hot rolling process.
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