Reasons for the formation of crack-like defects in 09Г2С heavy plate steel for tank steel structures

2020 ◽  
Vol 10 (5) ◽  
pp. 479-489
Author(s):  
Vitaly М. Goritsky ◽  
◽  
Georgy R. Shneyderov ◽  
Eugeny P. Studenov ◽  
Olga A. Zadubrovskaya ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Defect Formation ◽  
Steel Structures ◽  
Controlled Rolling ◽  
Plate Steel ◽  
Heavy Plate ◽  
Oil Storage ◽  
Magnetic Inspection ◽  
Metal Microstructure

Determination of causes of crack-like defects in the heavy plate steel 09Г2С is a crucial task, the solution of which is aimed at improving the mechanical safety of oil storage steel vertical tanks. In order to determine the causes for the formation of a group of crack-like defects oriented towards rolling, revealed during grinding and magnetic inspection of the tank wall surface near the vertical weld, the analysis of the chemical composition and testing of the mechanical properties of heavy plate steel were carried out, including the determination of the anisotropy of impact toughness in the temperature range from +20 to –75 °С, analysis of metal microstructure in the area of defect formation on transversal sections and rolled surface. Impact bending tests of 09Г2С heavy plate steel after controlled rolling in longitudinal and transverse directions showed no anisotropy of impact toughness, as well as high purity of steel as for sulfur and titanium, which at higher content causes impact toughness anisotropy. The revealed features of metal microstructure near the defects made it possible to conclude that the crack-like defects were formed during the rolling of gas bubbles at the stage of preparing semi-finished rolled products for finishing rolling. One of the possible methods to prevent such defects from getting into finished rolled products is the use of automated systems of visual inspection of rolled products in the manufacturing process.

INVESTIGATION OF THE TOUGHNESS OF LOW CARBON TEMPERED MARTENSITE IN THE SURFACE OF Ni--Cr--Mo--B ULTRA--HEAVY PLATE STEEL

2013 ◽  
Vol 48 (4) ◽  
pp. 401-406 ◽  
Author(s):  
Xiaoyong WANG ◽  
Tao PAN ◽  
Hua WANG ◽  
Hang SU ◽  
Xiangyang LI ◽  
...  
Keyword(s):  
Plate Steel ◽  
Low Carbon ◽  
Tempered Martensite ◽  
Heavy Plate

Design of a novel HSLA steel with a combination of high strength (140–160 ksi) and excellent toughness

2021 ◽  
Vol 112 (10) ◽  
pp. 800-811
Author(s):  
Mehdi Soltan Ali Nezhad ◽  
Sadegh Ghazvinian ◽  
Mahmoud Amirsalehi ◽  
Amir Momeni
Keyword(s):  
Impact Toughness ◽  
Yield Strength ◽  
Hsla Steel ◽  
Charpy Impact ◽  
High Strength ◽  
Controlled Rolling ◽  
The Other ◽  
Grain Structure ◽  
Charpy Impact Toughness ◽  
Fine Grain

Abstract Three steels were designed based on HSLA-100 with additional levels of Mn, Ni, Cr and Cu. The steels were prepared by controlled rolling and tempered at temperatures in range of 550–700°C. The continuous cooling time curves were shifted to longer times and lower temperatures with the increased tendency for the formation of martensite at lower cooling rates. The microstructures revealed that controlled rolling results in austenite with uniform fine grain structure. The steel with the highest amount of Mn showed the greatest strength after tempering at 750 °C. The top strength was attributed to the formation of Cu-rich particles. The steel with 1.03 wt.% Mn, tempered at 650 °C exhibited the best Charpy impact toughness at –85°C. On the other hand, the steel that contained 2.11 wt.% Mn and tempered at 700 °C showed the highest yield strength of 1 097.5 MPa (∼159 ksi) and an impact toughness of 41.6 J at –85°C.

scholarly journals A comparative study of beam design curves against lateral torsional buckling using AISC, EC and SP

2019 ◽  
Vol 15 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Vera V Galishnikova ◽  
Tesfaldet H Gebre
Keyword(s):  
Steel Structures ◽  
Reduction Factor ◽  
Steel Beams ◽  
Steel Beam ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Vertical Loading ◽  
Beam Design ◽  
Overall Stability

Introduction. Structural stability is an essential part of design process for steel structures and checking the overall stability is very important for the determination of the optimum steel beams section. Lateral torsional buckling (LTB) normally associated with beams subject to vertical loading, buckling out of the plane of the applied loads and it is a primary consideration in the design of steel structures, consequently it may reduce the load currying capacity. Methods. There are several national codes to verify the steel beam against LTB. All specifications have different approach for the treatment of LTB and this paper is concentrated on three different methods: America Institute of Steel Construction (AISC), Eurocode (EC) and Russian Code (SP). The attention is focused to the methods of developing LTB curves and their characteristics. Results. AISC specification identifies three regimes of buckling depending on the unbraced length of the member ( Lb ). However, EC and SP utilize a reduction factor (χ LT ) to treat lateral torsional buckling problem. In general, flexural capacities according to AISC are higher than those of EC and SP for non-compact sections.

Определение требуемой толщины вспучивающегося огнезащитного покрытия на стальных конструкциях для заданных пределов огнестойкости

2020 ◽  
Author(s):  
Yury Shebeko ◽  
Aleksey Shebeko ◽  
Andrey Zuban
Keyword(s):  
Fire Resistance ◽  
Confidence Level ◽  
Fire Retardant ◽  
Steel Structure ◽  
Steel Structures ◽  
Mean Square ◽  
Mean Square Deviation ◽  
R Value ◽  
The Given

Проанализирована взаимосвязь разброса значений пределов огнестойкости стальных конструкций со вспучивающимися огнезащитными покрытиями и соответствующего этому разбросу интервала толщины огнезащитного покрытия. Предложена методика, на основании которой может быть осуществлен выбор необходимой толщины огнезащитного покрытия в зависимости от заданных значений дисперсии предела огнестойкости и приведенной толщины конструкции при заданной доверительной вероятности.An analysis of a relationship between fire resistance limits scatter for steel structures coated with intumescent fire retardant coating and an appropriate interval of thicknesses of the coating was carried out. A methodology for the determination of this relationship was proposed. This methodology was tested on a practical example. A steel structure with a reduced thickness of 6 mm was considered. A typical dependence of the required thickness of the structure was taken into account. A ratio of a mean square deviation of the fire resistance limit to this limit was accepted to be equal 0.1. Using these values an appropriated interval of the thicknesses of the intumescent fire retardant coating was determined. This interval can be calculated for any given confidence level. Boundaries of this interval can be not symmetric in relation to the value of the normative thickness of the fire retardant coating. The proposed methodology can be used for the determination of the required thicknesses of the intumescent fire retardant coatings on steel structures for the given r value, reduced thickness of the structure and the confidence level.

Determination of the Ovality of Crude Oil Storage Tanks Using Least Squares

2011 ◽  
Vol 367 ◽  
pp. 475-483 ◽  
Author(s):  
R. Irughe Ehigiator ◽  
J.O. Ehiorobo ◽  
Ashraf A. Beshr ◽  
M.O. Ehigiator
Keyword(s):  
Crude Oil ◽  
Least Squares ◽  
Unbiased Estimate ◽  
Circular Cross Section ◽  
Field Measurements ◽  
Storage Tanks ◽  
Linear Measurements ◽  
Oil Storage ◽  
Least Squares Adjustment

In the processing of field measurements, the observations are adjusted using the least squares principle which gives unbiased estimate of the parameter sought together with their accuracies. In this paper, the use of the Least Squares model in the determination of the tank radius, centre point coordinates and ovality are discussed. The circular cross section of the crude oil storage tanks was divided into sixteen monitoring stations at equal intervals around the tank and at an elevation of 2m from the tank base. Total station instrument was then used to carry out angular and linear measurements by method of multiple intersection to reflectors held on the studs. The field measurements were post processed and adjustment of observation carried out by Least Squares adjustment method. The adjusted coordinates together with the computed radius were then used to determine tanks ovality. All data processing and adjustment were carried out with the aid of MATLAB Software for the 2003, 2004 and 2008 measurement epochs.The results of the study revealed an expansion of the tank shell between 2004 and 2008 measurement epoch. The radius of the tank was computed to be 38.187m in 2003 and 2004 and 38.205m in 2008 respectively.

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