In this paper is studied the hot plastic deformability (plasticity and resistance to deformation) for the low-alloyed steel of heat treatment for mechanical engineering in two ways: compression and tension. Groups of low alloy steels is very important in terms of quality and quantity, the products of these steels have developed internal and external market. The plasticity variation were plotted with the temperature and it was established that the plasticity of the steel increases in the range 700-12000C, then decreases as a result of the firing of the grain boundaries, for the bars obtained from ingot and continuous cast blown it was noticed that the plasticity values are very close. Deformation resistance decreases as the temperature increases. The finest granulation was obtained for a final plastic deformation temperature of 8000C and a minimum degree of deformation of 45%.

In this paper is analysed the air quality in urban areas in Bucharest, the analysis was based on the monitoring of the average concentration of particulate matter PM 10, nitrogen oxides, NO2, and sulfur dioxide, SO2 in Bucharest between 2009-2015. The analysis refers to the maximum concentration of 24 h and the occurrence of overruns beyond the limit set. It also looked at the wind regime, air quality and temperature influence on air pollution in Bucharest between 2009-2015.

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In this paper, optimum hot formation processing parameters for 31VMn12 steel were established, the torsion deformation of 31VMn12 steel was investigated at temperatures from 900, 1000, 11000C and strain rates from 0.05 s-1 to 3 s. -1. There were studied the structural aspects of materials, in microstructures by electronic microscopy. The stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zenner-Hollomon parameter. The mathematical model presented in the paper describes the relationship of tension strain, voltage and temperature coefficient 31VMn12 steel at high temperatures. The stress-strain curves determined by the torsion test allowed the calculation of the Zenner-Hollomon parameter corresponding to the maximum stress. By using this parameter has established a set of equations that reproduce completely stress-strain curve, including the hardening, the restoration and dynamic recrystallization area. Comparisons were made between the experimental results and the predicted and confirmed that constitutive equations developed can be used for mathematical modelling and other attempts (forging, compression) and other types of steel.

Considering the importance of gaseous and/or liquid fuels impact on the environment, the resistance of pipelines at hot plastic dejbrmation is important. Therefore, in order to avoid or reduce any adverse impact on the environment, the influence of residual copper on hot deformability of steel pipes was investigated in this paper. The negative copper influence was experimentally proved using torsion deformation at temperatures above 1000", under the air and argon atmosphere. The samples were heated and then deformed at different temperatures with constant deformation rate. Also, structural analysis of investigated materials was done, using metallographic and SEM analysis.

Considering the advantages of steel surface hardening, when less expensive low-and medium-carbon steels can be surface hardened without the problems of distortion and cracking associated with the through hardening of thick sections, we developed some research entailing the increase in environmental performance of iron powders carburizing process using methane as carrier. Apart of studies on optimal working parameters and methods, our research addresses improvements in environmental performance of process by selecting powders suppliers, reducing raw materials and energy consumptions, considering products life cycle analysis. A comparison is also performed among the characteristics of three series of research for obtaining ecological steels for automotive industry.

In Romania, for more than 50% of the amount of sewage sludge, the life cycle ends with the most unfavorable stage of the waste management hierarchy or storage. This study indicates the feasibility of using sewage sludge as an alternative fuel in clinker rotary kilns by presenting theoretical information and personal research data.

In this paper we analyze the influence of the number of laser pulses on the hardness of the metal. We have shown that the hardness increases with the number of laser pulses due to the increase in the probe surface temperature, especially by increasing the superficial absorption of laser radiation. Optical microscopy was analyzed by the metallographic aspects of the target in OLT 65, Al, Cu, laser irradiated.