The presented paper deals with a numerical simulation of casting and solidification of a 65-ton ingot made of 25CrMo4 low-alloy chrome-molybdenum steel. The aim was to focus on the assessment of steel melt flow, the risk of formation of microporosity and segregation according to Niyama or Suzuki criteria respectively, solidification. The numerical simulation was done for parametric analysis of solidification process in casting based on boundary conditions. Correctly set values of casting parameters like casting speed, casting temperature of steel, H/D ingot ratio are the essential precondition to minimize the defects of steel ingots.

The paper presents laboratory physical modeling of the seamless tubes production, specifically the first step of the Mannesmann production process, the so-called punching. A "Universal rolling mill" at MATERIAL & METALLURGICAL RESEARCH Ltd. was used for experiments. The experimental material was micro-alloyed steel. The tests were carried out at four different heating temperatures and at different rpm speeds of the working rolls. The other settings of the rolling mill remained the same. In terms of the geometrical parameters, the biggest necking of the punched sample (preferably at both ends) was observed with increasing temperature and strain rate. The torque decreased with increasing temperature and with lower speed of working rolls. The punching time and the total current power consumption decreased with increasing temperature and with a higher deformation rate.