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Mechanical properties of a steam tube made of CrMo creep resistant steel are analysed in this contribution after up to 2,6⋅105 hours service life in creep conditions at temperature 530 °C and calculated stress level in the tube wall 46,5 MPa. During service life there were in the steel gradual micro structure changes, first pearlite spheroidization, precipitation, coaugulation and precipitate coarsening. Nevertheless the strength and deformation properties of the steel (Re, Rm, A5, Z), and the resistance to brittle fracture and the creep strength limit, were near to unchanged after 2,1⋅105 hours in service. The steam tube is now in service more than 2,6⋅105 h. [ABSTRACT FROM AUTHOR]

Grain refinement upon the severe plastic deformation (SPD) at low temperatures (below the recrystallization temperature) and an unusual improvement the properties of such materials are shown reliably. However, the industrial application is limited due to the absence of effective continuous SPD processes. The potential of development of continuous SPD processes based on the equal channel angular pressing (ECAP) process from one side and continuous extrusion or drawing processes from another side is considered. Existing various continuous SPD processes for strip, rod and wire production are analyzed. [ABSTRACT FROM AUTHOR]

First the paper presents a review of steel production of the tubes in world: possible potencial is about 110 x106 the tons (35 x 106 seamless tubes, rest welding tubes). In 2007. y. was record volume of 88,6 x 106 tons inworld; 6,5 % of total production of steel in world. Ratio-weldeds tubes: seamless tubes 70:30 %. Further in the article are presented urgent the problems of the pipe and tube industry. [ABSTRACT FROM AUTHOR]

The results of research of microstructure of the strips from low carbon steel 45x6 and 30x8 mm in hot-rolling condition and after accelerated cooling of different intencity and schemes of the coolers movement in the cooling chambers are shown. The strengthening layer is spread unevenly along the perimeter of the rolled steel. The formation character of the structure and its spreading along the cross-section depends on intensity of cooling and the ratio of the width of the stripe to its thickness. Regimes, that provide the high level of steel’s strength with the smallest changing of the mechanical properties by the length of the rolled strip were defined.

The main purpose of this paper is to give a mathematical description of flow stress of examined aluminium alloys on the basis of upsetting tests performed in a servohydraulic plastometer. Deformation curves have been described by means of the Sellars-Tegart-Garofalo equation, with the aid of linear regression analysis and by the neural network method implemented in the NEUREX program. [ABSTRACT FROM AUTHOR]