The paper presents a detailed description of the process of creation of a surface alloy layer (using high-carbon ferrochromium) on the cast steel casting. The mechanism of the surface alloy layer is based on the known theories [5,6]. The proposed course of formation of the layers has been extended to decarburization stage of steel. The research included proving the presence of carbon-lean zone. The experiment included the analysis of the distribution of elements and microhardness measurement.
Casting quality depends on many factors including the quality of the input materials, technology, material securing and last but not least, the mould into which the casting is casted. By pouring into a single-shot mould, based mainly on 1st generation binders, is is a very important factor. Basically, a bentonite mixture represents either a three- or four-component system, but each component of the system is a heterogeneous substance. This heterogeneity punctuates mainly a non-stationary heat field, presented throughout the whole process of the casting production. The most important component is a binder and in the case of first generation binders mostly bentonites are used - clays that contain minimum of 80% of montmorillonite
The paper addresses the macro- and microsegregation of alloying elements in the new-developed Mn-Al TRIP steels, which belong to the third generation of advanced high-strength steels (AHSS) used in the automotive industry. The segregation behaviour both in the as-cast state and after hot forging was assessed in the macro scale by OES and by EDS measurements in different structural constituents. The structural investigations were carried out using light and scanning electron microscopy. A special attention was paid to the effect of Nb microaddition on the structure and the segregation of alloying elements. The tendency of Mn and Al to macrosegregation was found. It is difficult to remove in Nb-free steels. Microsegregation of Mn and Al between austenite and ferritic structural constituents can be removed.
In this article the main problems related with the proper choice of the design and operation parameters of vacuum installation in vacuum moulding system have been discussed. In such system a vacuum are generated using electric-driven vacuum pumps. The aim of the experiment is to evaluate the performance of a vacuum system basing on registered plots of selected electric power parameters of the power-supplying system of the pumps with parallel measurements instantaneous values of pressure in selected points of model stand. The measurements system for power-supply unit has incorporated the recorders of instantaneous current and voltage values. Following the suitable numerical procedure, the experimental data are analysed to yield mathematical relationships between the variations of the generated vacuum pressure levels and variations of selected electric power parameters. According to the authors, the applied measurements system of the parameters of a vacuum-assisted installation may become an effective and easy practical method of evaluating the performance of such installations, used also in industry.
In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast proces so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic unalloyed cast steel, whereas working part (layer) is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.