Fundamental Evaluations on Microstructure and Mechanical Properties of on-Line Normalizing Processed V-N Microalloyed N80 Class Oil Casings

Zhao, Shuangshuang; Wang, Q.F.; Pan, Tao; Zhang, C.Y.; Su, Hang; Yang, Chen; Yan, Zhongjie; Zhang, Y.Q.

doi:10.1016/s1006-706x(08)60084-9

Cited by 8 publications

(5 citation statements)

References 4 publications

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“…7(e). Many research reported that Mo remarkably enriches in the inner rust layer as MoO 3 or FeMoO 4 , increase the density of rust layer and enhance the protective effect of rust layer and improve the corrosion resistance. 20) Clearly, oxide film of C-Mn-Mo-QT surface is endowed to improved passivation ability and could prevent the penetration of chloride ions and water molecules into the steel matrix than that of C-Mn-CC.…”

Section: (4)mentioning

confidence: 99%

“…1) However controlled rolling and controlled cooling has not yet successfully applied in seamless pipe production at present, because seamless pipe production process and deformation process involved are too complex to control. [2][3][4] Therefore quenching and tempering treatment after hot-rolled are usually employed in producing high grade seamless steel pipes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Corrosion Behavior of Seamless Pipeline C–Mn Steel by On-line Controlled Cooling Technique

Li¹,

Zhang

et al. 2018

ISIJ Int.

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Section: (4)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Corrosion Behavior of Seamless Pipeline C–Mn Steel by On-line Controlled Cooling Technique

Li¹,

Zhang

et al. 2018

ISIJ Int.

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“…An increase in reheating temperature brought elevated strength at an expense of toughness. Improved combination of yielding strength in 650 MPa and toughness in 48 J at −20˚C can be obtained in 33 Mn2V stee1 with nitrogen content of 140 ppm at reheating temperature of around 930'C [92].…”

Section: Role Of Vanadium-nitrogen Micro-alloyingmentioning

confidence: 99%

“…Zhao et al [92] indicated that, in ferritic-pearlitic microalloyed steel, the area fraction of ferrite increased from 21% to 38%, and the averaged grain size decreased from 10.3 µm to 6.2 µm, when the nitrogen content was enhanced from 30 ppm to 210 ppm and normalization was performed at 930˚C. An increase in reheating temperature brought elevated strength at an expense of toughness.…”

Section: Role Of Vanadium-nitrogen Micro-alloyingmentioning

confidence: 99%

Recent Trends in Producing Ultrafine Grained Steels

Halfa¹

2014

JMMCE

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Ultrafine grained steels with grain sizes below about 1 µm offer the prospect of high strength and high toughness with traditional steel compositions. These materials are currently the subject of extensive research efforts worldwide. Alloy design is one of the first considered issues, while designing new steel with targeted mechanical properties. However, the alloying content of steel does not fully determine the mechanical properties, but manufacturing procedure, hot rolling and cooling parameters, heat treatment parameters etc. are also of vital importance. For instance, same steel with different processing conditions can exhibit rather large variations in properties. To be precise, chemical composition with the processing parameters determines the microstructure, which in turn determines the properties of the steel. Steel is defined as an iron alloy containing C, Mn and Si that are generally used as alloying elements in steel. Micro-alloying elements such as Nb, Ti V, and B, are considered to be effective, causing strengthening as well as microstructural refinement in small quantities below 0.1 wt% (therefore these are called micro-alloy elements) and are quite generally used in ultrafine grain steel. Substitution alloying elements, such as Mo, Ni, Cr and Cu are alloyed to suppress phase transformation temperatures, i.e. for reaching certain level of strengthening, since the strength of steel structures strongly depends on the phase transformation temperature. Accordingly, the alloy design of ultrafine grains steels with different structures generally relies on: i) carbon levels, ii) sufficient alloying to obtain the desired transformation temperature and iii) micro-alloying technology in conjunction with Thermo Mechanical Controlled Processes (TMCP). Also, both advanced thermo-mechanical processes and severe plastic deformation strategies are used to produce ultrafine grained steels. Both approaches are suited to produce submicron grain structures with attractive mechanical properties. This overview describes the various techniques to fabricate ultrafine grained steels.

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“…Oil casing steel N80 has been widely used as the main material for the dual line construction of gas transporting project from west to east in China due to its high mechanical property and excellent corrosion resistance [1][2][3]. Since oil casing steel often should endure a dynamic loads or impact with the fluctuation of oil and gas, fracture [4] and corrosion [5] fatigue of steel are unavoidable failures during its in-serving life.…”

mentioning

confidence: 99%

Effect of Intercritical Quenching on Microstructure and Mechanical Properties of Oil Casing Steel N80

Huang

Wang

Zhang

et al. 2013

AMM

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In order to improve the toughness of oil casing steel N80 without the sacrifice of its original high strength, an intercritical quenching treatment was conducted under the temperature determined by a differential scanning calorimetry (DSC) analysis. Effects of intercritical quenching on the microstructure of oil casing steel N80 were characterized by means of optical microscope (OM) and scanning electron microscope (SEM). Tensile strength, reduction of cross-sectional area and microhardness were measured to evaluate the mechanical property of oil casing steel N80 after intercritical quenching treatment. The study results show that the tensile strength and microhardness of intercritical quenched oil casing steel N80 consisting of ferrite (F) and martensite (M) is slightly lower than that of tempered oil casing steel N80 composing of sorbite (S), yet which is still higher than that of full annealled oil casing steel N80 composing of pearlite (P) and a little amount of ferrite (F). In particular, the reduction of cross-sectional area of oil casing steel N80 intercritical quenched at 740°C is higher than those of tempered and full annealled. Additionally, both dimple and cleavage can be found on the impact fracture surface of N80 steel after intercritical quenching at 740°C. The toughness of oil casing steel N80 can be obviously improved by the intercritical quenching treatment at 740°C due to the formation of ferrite (F).

show abstract

Fundamental Evaluations on Microstructure and Mechanical Properties of on-Line Normalizing Processed V-N Microalloyed N80 Class Oil Casings

Cited by 8 publications

References 4 publications

Corrosion Behavior of Seamless Pipeline C–Mn Steel by On-line Controlled Cooling Technique

Corrosion Behavior of Seamless Pipeline C–Mn Steel by On-line Controlled Cooling Technique

Recent Trends in Producing Ultrafine Grained Steels

Effect of Intercritical Quenching on Microstructure and Mechanical Properties of Oil Casing Steel N80

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