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

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.

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Ultra-Low Carbon Bainitic Steels for Heavy Plate Applications

10.21236/ada236859 ◽

1990 ◽

Author(s):

C. I. Garcia ◽

A. J. DeArdo

Keyword(s):

Low Carbon ◽

Heavy Plate ◽

Bainitic Steels

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Development of High Efficiency Welding for Heavy Plate Steel Using High Current Buried Arc

JOURNAL OF THE JAPAN WELDING SOCIETY ◽

10.2207/jjws.86.510 ◽

2017 ◽

Vol 86 (7) ◽

pp. 510-514

Author(s):

Hayato BABA

Keyword(s):

High Efficiency ◽

Plate Steel ◽

High Current ◽

Heavy Plate ◽

High Efficiency Welding

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Development of NbTiB Microalloyed HSLA Steels for High-Strength Heavy Plate

Materials Science Forum ◽

10.4028/www.scientific.net/msf.500-501.565 ◽

2005 ◽

Vol 500-501 ◽

pp. 565-572 ◽

Cited By ~ 3

Author(s):

H. Meuser ◽

F. Grimpe ◽

S. Meimeth ◽

C.J. Heckmann ◽

C. Träger

Keyword(s):

High Strength ◽

Optimum Process ◽

Low Carbon ◽

Low Alloy Steel ◽

Alloying Element ◽

Heavy Plate ◽

Hsla Steels ◽

Bainitic Microstructure ◽

Bainitic Structure ◽

Low Temperature Toughness

This paper deals with the development of low carbon NbTiB micro-alloyed high strength low alloy steel for heavy plates with high wall thickness. In the production of heavy plate it is remarkably difficult to achieve a combination of high strength and good low-temperature toughness. Bainitic microstructures have shown the capability to attain such requirements. To achieve a bainitic microstructure even for heavy wall products the formation of bainite can be promoted and supported by the use of small amounts of boron as a micro-alloying element. This industrial research project is based on the addition of small amounts of boron to promote the desired bainitic structure. Mill rolling trials were carried out to determine the optimum process parameters. The results of experimental mill rolling trials on 35 mm plates will be presented in this paper.

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