International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper presents the results of research focused on the renovation of worn surfaces. Four progressive welding technologies were used – Cold Metal Transfer, MIG Pulse, TOP-TIG and laser technology. The layers were evaluated by non-destructive tests – visual, capillary and ultrasonic methods. The layers were evaluated under dry-friction adhesive wear conditions by the Ball-On-Disc method. A Si3N4 bead was used. Analyzes confirmed the impact of the renovation method on the quality of the resulting surface.

The paper presents the results of research aimed at determining surface wettability. The research was focused on microtexturing by low-energy laser irradiation of the surface of molded parts using innovative engraved surface treatment methods (LBT and EBT) to ensure a smooth distribution of the separation agent on the surface of high-pressure Al castings. The basic material was Uddeholm Dievar, which is used to make molds. PVD coatings were applied to the base material. The effect of laser texturing surfaces on the contact angle size was determined. Contact angle was evaluated on the base material, on PVD coatings without surface treatment and with the use of two types of separating agents.

The paper focuses on the evaluation of the quality of fillet welds produced robotically by the method of impulse synergic welding MAG. This welding technology is used in the automotive industry in the production of rear seat backs for passenger cars. In the process of automated production, the speed of the process, accuracy, and quality of the made joints are important. Several factors affect the accuracy and quality of welded joints. The paper presents the results of research where the influence of filleting of fillet welds on their quality was confirmed. Visual and capillary methods were used to determine the quality of welds, metallographic analysis for evaluation depth of weld root penetration, strength properties of welds were evaluated by static tensile test. Statistical ANOVA methods were used to process the obtained values. Experimental work confirmed that the depth of welding of the weld root into the base material has the greatest influence on the final quality of fillet welds. It is this parameter that results in the elimination of the weld and thus the entire produ ct.

Molds designed for high-pressure casting of aluminum are exposed to very intense thermal, mechanical but also chemical stress during their operation. This stress leads to a synergistic effect of a combination of high-temperature corrosion processes in molten metals, under real conditions associated with mechanical wear. High-temperature corrosion in the environment of liquid metals occurs in the foundry industry, when casting molten metal most often into steel molds. Repair of worn parts of molds by welding, which can be performed even after their irreversible surface degradation, is a very efficient, cost-effective and envi-ronmentally acceptable form of their maintenance, while the chemical and physical properties are welded layers if they exceed the properties of the original material.

At present, various types of steel grades are used in the production of welded structures and assemblies, resp. combinations of ferrous and non-ferrous metals. In these mutual combinations, it is necessary to know the specifics of weldability of both materials, to choose a suitable welding technology and a suitable filler material. In the experimental part, the quality of heterogeneous welded joints was verified by the GMAW method. A protective gas atmosphere of 82% Ar + 18% CO2 was used for welding (M21 – ISO 14175: 2008). The possibilities of welding and mutual combinations of austenitic stainless steel with structural non-alloy steel, structural alloyed high-strength steel with structural non-alloy steel were assessed. The quality of welds was evaluated using non-destructive and destructive tests in terms of standards: visual test STN EN ISO 17637, capillary penetration test STN EN ISO 22476-12, internal errors were evaluated using radiation tests STN EN ISO 17636-1. The destructive tests used the tensile test STN EN ISO 6892-1, the weld fracture test STN EN ISO 5173 and the Vickers hardness test STN EN ISO 6507-1, the bending impact test STN EN ISO 9016 and the metallographic analysis according to STN EN ISO 17639.

The paper focuses on the degradation of molds that are used for the technology of high-pressure casting of Al and its alloys. The method of high-pressure casting of aluminum products is one of the widely used production methods, which at the same time meets the requirements for precision and productivity in the production of cars and various mechanical parts. In the high-pressure casting process, the molds are exposed to various thermal and mechanical loads, where the molds and their shaped parts are degraded. The paper presents the results of research focused on the use of duplex PVD coatings to increase the life of shaped parts of molds for high-pressure casting of Al and its alloys.

The paper presents the possibilities of renovation of worn functional surfaces of roll for continuous steel casting. The cylinder was made of steel 24CrMoV55 – DIN 17240. The lifetime of the continuous casting line roll is limited by the quality of their functional surface. The worn roll is decommissioned and the extent of its damage has been assessed. Cracks are a limiting factor in deciding on its renovation. Renovation of functional surfaces of roller from a diameter of ø 200 mm is realized by technology submerged arc welding (SAW). The article presents the results of research into the quality of newly formed cladding layers. Their quality was evaluated using non-destructive and destructive tests. Based on the performed experiments, it can be stated that the used surface renovation procedure is suitable for the renovation of functional surfaces of continuous steel casting rolls.

The paper presents the results of quality evaluation of weldments produced by a mutual combination of different steel grades. Weld joints were made using GMAW technology (method -135 ISO 4063). The type of welding parameters used for the quality of welded joints was monitored. The quality of welded joints was assessed using non-destructive tests. In non-destructive tests, the Visual test according to EN ISO 17637, the Penetration test with colour indication according to EN ISO 22476-12 was used to identify surface defects. The presence of internal errors was assessed by a radiation test according to EN ISO 17636-1. Within the destructive tests, the quality of the welds was assessed by a tensile test according to EN ISO 6892-1, by the test of brittleness of welds according to EN ISO 5173, the course of hardness according to EN ISO 6507-1 was determined on transverse cuts. The bending impact test according to EN ISO 9016 will determine the toughness of the weld metal and heat-affected areas. Metallographic analysis of welds according to EN ISO 17639 was performed on transverse metallographic sections using light microscopy. Based on the performed experiments, recommendations were set, or proposed changes in the welding procedures of the given steel grades.

The paper presents the results of research focused on the restoration of functional areas of products by the application of PTA technology. Hardfacing layers intended for the renovation of the surfaces of aluminum alloy injection molds were evaluated. The base material was medium alloy steel X38CrMoV5-1 (H11). Three types of powder additives were applied to form the functional layers: two types based on iron, designated HSS 23 and HSS 30, and one type based on nickel, designated DEW Nibasit 625 -P. The quality of the layers was evaluated using non-destructive and destructive tests. The surface integrity of the layers was assessed by visual and capillary tests. The microstructure of the materials and its hardness were evaluated. The tribological properties of the welds were determined by the pin-on-disc method.

The paper presents the results of research aimed at determining the quality of welds in steel and aluminum alloys. Laser welding technology, fusion-pressure welding in combination with adhesive bonding were used for joining. The present research describes a new bonding technology based on the resistance welding process with a combination of adhesive bonding. Its implementation allows the joining of aluminum and steel sheets at extremely short welding times with a high concentration of energy in combination with adhesive bonding. The quality of the joints was determined on the basis of the tensile shear test according to ISO 12996.

The paper presents the results of the research aimed at determining the quality of coatings applied by the HVOF spray coating technology and the advances in its application. WC-Co-Cr 86/10/4 nano covers were evaluated at two grain sizes. The effect of nano particle size on coatings quality was evaluated under abrasive wear conditions with bound abrasive in the initial state and after thermal cyclic loading. Coating thickness measurements, microhardness and structural analysis of the coatings were performed. As the number of thermal cycles increased, the hardness of the coatings increased. A thermal load between 600 and 800 ° C results in the crystallization of the amorphous phase, which leads to the precipitation of the WC phase from the Co-Cr matrix, and thus to an increase in the microhardness of the coating. The REM analysis of the structure of nano coatings confirmed that the exposure of the samples to the thermal load had an influence on their structural  composition. As the number of thermal cycles increased, the wear of the coatings under dry friction conditions increased.

The paper presents the results of the research focused on the determination of the quality of adhesive joints of cold rolled sheets in the automotive industry. DC05 galvanized sheet was used for joints. A progressive type of adhesive used in the automotive industry was chosen. The shear and peel strength of the adhesive joints according to Winter were determined. The strength of the joints was determined depending on the cure temperature of the adhesive. After tests, the character of fracture surfaces of adhesive joints was evaluated.