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The study of the surface quality of the thin wall bearing units to rolls roller seats pipe conveyor

Michalik P., Zajac J., Fabianova J., Mital D.

Advances in Science and Technology. Research Journal

2017

Vol. 11, no 2

192--197

The article deals with the study of surface roughness of thin-walled houses bearing rollers for roller mills. The size and shape of the rear end housing was designed in order to measure the surface roughness of the inner cylindrical bearing surface with a wall thickness of 4, 5 and 6 mm. For comparison the roughness was measured also on the wall with a thickness 26 mm. The welded housing and the base plate was clamped in the machine vice jaw with a width of 150 mm. Material components bearing small house has been fine-grain weld able steel bearing S355. For finishing the hole with a diameter of 40 mm, a tool with a diameter of 32 mm was used with three cutting blades SDXT09M405R MM. Spindle speed was 1350 rev / min. Tool feed speed was 850 mm / min. The surface roughness was measured with a Mitutoyo SJ 400th.

GNSS for an Aviation Analysis Based on EUPOS and GNSS/EGNOS Collocated Stations in PWSZ CHELM

Fellner A., Cwiklak J., Jafernik H., Trominski P., Zajac J., Banaszek K.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2008

Vol. 2, no. 4

351--356

Under the umbrella of PWSZ Chelm, taking account of future implementation of navigation using EUPOS and GNSS based on EGNOS several planned actions were carried out in the 2005-2006. The actions in particular contribute to: 1. ICAO and EGNOS requirements and coverage area (Chelm Town located near Polish-Ukrainian border is also at the east border of planned EGNOS coverage for ECAC states). 2. Preparatory activities to establishing the EUPOS station in PWSZ Chelm. Cooperation of PWSZ Chelm and ULC (Polish Aviation Regulator) in the frame of conventional NAV aids use and GNSS implementation in aviation. 3. Analysis of ICAO requirements and methods of testing SIS (Signal In Space) needed to certify GNSS in Poland for use for an aviation. 4. Preparatory activities to establishing the EGNOS SIS monitoring station based on EUROCONTROL Pegasus software and GNSS/EGNOS receiver Septentrio PolaRx2e. 5. Analysis of methods for exchange of information between EUPOS and EGNOS SIS station to initiate the application of satellite positioning systems to air navigation in Poland. The project EUPOS is a European initiative aiming at establishment of a uniform DGNSS (Differential Global Navigation Satellite System) basis infrastructures in Central and Eastern European countries including Chelm Town where PWSZ is localized playing vital role in GIS/GNSS implementation in the region and Polish aviation.

Hydrogen diffusion in micro alloy steels

Sojka J., Jonšta P., Rytířová L., Jerome M., Zajac J., Sozanska M.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

2007

Vol. 321, z. 89

121-122

Petroleum and natural gas systems can be contaminated with wet H2S. This environment is very aggressive to the steels used in the transport and processing of these products and it can result in various forms of hydrogen embrittlement. The reaction between wet H2S and the steel generates atomic hydrogen, which can be, at least partially, absorbed into the steel. In the absence of applied stress, the diffused hydrogen can cause hydrogen induced cracking (HIC). The resistance of steels to HIC is closely related to the microstructure features: nonmetallic inclusions, hard phase constituents, banded structures etc. In the presence of applied or residual stress, the failure process can occur by sulphide stress cracking (SSC) or stress oriented hydrogen induced cracking (SOHIC). In the case of SSC, steel resistance is commonly derived from its strength level. It is generally accepted that steels having tensile strength less than 690 MPa approx. are resistant to SSC. The role of microstructure is not emphasized although there are some works showing that microstructure can also play an important role in the case of SSC. In the previous works, it was proved that even in case of SSC the resistance of the steels can be improved by the heat treatment – quenching and tempering, if the banded structure of ferrite and pearlite is replaced by the tempered martensite and/or bainite. The resistance of the steel to the hydrogen embrittlement is affected by both the microstructure and hydrogen concentration. To understand the hydrogen embrittlement it is necessary to characterize also the hydrogen transport – diffusion. In this work hydrogen diffusion coefficient in micro alloy X52 and X60 API steels (tubes), having different microstructures - banded ferrite and pearlite after hot rolling and the mixture of tempered bainite and martensite after quenching and tempering, are evaluated. The role of specimen orientation is also taken into account.