Prospects for development of load-carrying elements of freight car bogie

Abstract

In recent years accidents related to fracture of cast load-carrying elements of three-piece bogies of freight cars have become more frequent in the railways of Ukraine and Russia. The work substantiates the rationality of development and application of all-welded load-carrying elements of freight car bogie (FCB), improving their operational reliability. Welded structures of FCBs are widely applied in West Europe. Attempts to develop structures of all-welded elements of FCBs irreplaceable with cast structures are made in Ukraine and Russia. However, none of the developed welded structures is currently applied at regular cargo transportation, because of non-optimal design of bogie welded elements in terms of ensuring the required fatigue resistance margin. To develop a competitive welded solebar and bogie bolster it is, first of, all necessary to increase the fatigue resistance of bogie elements, improve the accuracy of solebar fabrication to avoid skewing of wheelset axles, leading to fast wear, lower their weight and cost, increase element run between scheduled depot repairs. Strength analysis of bogie welded elements should be performed in keeping with the norms currently in force, as well as current world standards, norms and recommendations, allowing for the most recent achievements in the field of dynamics of railway cars and methods to determine welded joint fatigue resistance. 20 Ref., 8 Figures.

Numerical and Experimental Study of Phase Transformations in Welding Processes / Badania Numeryczne I Doświadczalne Przemian Fazowych W Procesach Spawania

“…Authors of [26] developed CHT diagram for higherstrength steel heated at different rates. Further, by the use of equations of the kinetics of phase transformations and results of the experiment they gave a formula for temperature changes during heating in the function of heating rates: (6) where Ac 1,3 are equilibrium temperatures (Ac 1 and Ac 3 ), v H is a heating rate, t is a time above static Ac 1 and Ac 3 temperatures.…”

“…In the heat affected zone material is exposed to a very different thermal conditions and the resulting HAZ structure in welded steel highly depend on thermal cycle parameters, such as: heating rate, maximal heating temperature and cooling rate. In the analysis of phase transformations during welding the attention is mainly focused on phase transformations during cooling process [3][4][5][6][7][8][9][10]. The analysis of the kinetics of phase transformation is carried out by well known mathematical models found in the literature and Continuous-Cooling Transformations (CCT) diagrams.…”

Fatigue calculation for welded joints of bearing elements of freight car bogie

“…Using of welding technologies for manufacture of indicated parts from sheet products for increase of their service reliability characteristics under alternating loads is promising [3].…”