Apart from reducing the processing energy, hardening and tempering of near-net shape forged components from their forging heat primarily promises shortened conventional process sequences. In this case, the continuous cooling transformation diagrams (CCT diagrams) found in the literature can only be used as a rough approximation of microstructural transformations during the heat-treatment. The reasons for this are that firstly, the deformation influences the transformation kinetics and secondly, the deformation temperatures are comparatively high. Therefore, both deformation CCT diagrams and, for reference purposes, CCT diagrams without deformation were determined for a selection of heattreatable steels (34CrMo4, 42CrMo4, 52CrMo4, 51CrV4, 34NiMo6) at the heating temperature of 1200 8C and deformation levels of 0.3 and 0.6.

An analysis of the parameters of multi-stage controlled strip cooling during the process of rolling of 5.5 mm-diameter C70D high-carbon steel wire rod has been made in this publication. Investigations included also the analysis of the flow rate of the cooling medium and its pressure in the devices for accelerated and controlled cooling of the strip directly in the rolling line, as well as in the STELMOR line. The investigations carried out within the study have determined the cooling capacity of the accelerated strip cooling devices for specific (preset) cooling conditions. The scope of the investigations also encompassed the analysis of the effect of the employed cooling conditions on the temperature distribution and on the properties and microstructure of the steel studied. Moreover, physical modeling of the currently applicable technology of rolling the investigated steel grade was also performed.

The fast development of automotive industry effects significantly on aspirations of designers and constructors to reduces the mass-produced cars, affecting meaningly on fuel consumption and gas emition. From the standpoint of automotive industry materials for modern car-body sheets should have high mechanical properties (primarily high tensil strenght) and very good cupping. The required high mechanical and plastic properties steels used in produce of car bodies are dependent on the type of the obtaining structure, witch be shaped by an appropriate heat and thermo-plastic treatment. The modern steels used in automotive industry are multi-phase steels e.g. dual-phase (DP), complex-phase (CP) and transformation induced plasticity (TRIP) steels. In this paper are presented the results of physical and numerical modeling of heat treatment the experimental complex-phase steel, witch be conducted in the Institute of Modeling and Automation of Plastic Working Processing on Częstochowa University of Technology. The numerical modellig of heat treatment were carried with using the commercial programe TTSteel. Based on the results of computer simulation the changes of steel microstructure during continuous cooling were analyzed and the characteristics temperature and CCT diagram was constructed. Numerical research have been verified by the physical simulation of heat treatment by the dilatometer DIL805. The characteristic temperature of investigated steel and the size of initial austenite grains were determined. On the samples was also metallographic examination and Vickers hardness testing conducted. The obtained results were used to build a real CCT diagram of steel.

The research presented in the current paper was carried out for the experimental steel designed for plate which meets the requirements for grade X100 according to API5L. Physical modeling of the rolling process was carried out using the GLEEBLE 3800 simulator. The tested steel is fine-grained constructional steel for making tubes for gas pipelines with the working pressure higher than 15 MPa. The fine-grained structure guarantees excellent plastic properties as well as high impact toughness. After rolling the steel should obtain the minimal yield point of 690 MPa and tensile strength over 760 MPa.

In the machine, metallurgical, and shipbuilding industries, steel products with alloy and composite coatings based on nickel may be used. It is expedient to improve the physicochemical properties of the surface layer of products as they have a significant roughness value after thermal spraying. It is therefore important to finish the layers applied by flame spraying, where machining is used for this purpose. However, it causes a loss of coating material, which is quite expensive. Therefore, in order to reduce costs and improve the quality of the surface layer, the finishing treatment of nickel-based coatings by means of plastic working is used. Two types of plastic working were proposed: rolling and burnishing. Numerical and experimental tests of the plastic processing of alloy coatings were carried out. The roughness of the coatings after rolling decreased to 1/25 and 30% strengthening of the alloy coating matrix was determined. After burnishing, roughness was reduced to 1/12 and the alloy coatings were strengthened by 25%. Plastic working by rolling and burnishing has a beneficial effect on the surface quality of the workpiece, not only by significantly improving the roughness, but also by increasing the strength properties of the surface layers.