The paper presents the analysis of temperature fields, phase transformations, strains and stresses in a cuboidal element made from S235 steel, surfaced with multipass GMA (Gas Metal Arc) method. The temperature field is described assuming a dualdistribution heat source model and summing up the temperature fields induced by the padded weld and by the electric arc. Dependence of stresses on strains is assumed on the basis of tensile curves of particular structures, taking into account the influence of temperature. The calculations were carried out on the example of five welds in the middle of the plate made of S235 steel. The simulation results are illustrated in graphs of thermal cycles, volume shares of structural components and stresses at the selected points of cross-section, and the temperature and strain distributions in the whole cross section.

The application of hardfacing is one of the ways to restore the functional properties of worn elements. The possibility of using filler materials rich in chrome allows for better wear resistance than base materials used so far. The paper presents the results of research on the use of 3 different grades of covered electrodes for the regeneration of worn track staves. The content of the carbon in the covered electrodes was from 0,5% to 7% and the chromium from 5% to 33%. The microscopic and hardness tests revealed large differences in the structure and properties of the welds. The differences in the hardness of the welds between the materials used were up to 150 HV units. The difference in wear resistance, in the ASTM G65 test, between the best and worst materials was almost 12 times big.

This research is focused on the analysis of heat-affected sub-zones in 2 mm thick steel S960MC samples, with the aim of observing and evaluating the mechanical properties after exposure to temperatures corresponding to individual heat-affected sub-zones. Test samples were prepared using a Gleeble 3500 thermo-mechanical simulator. The samples were heated in the range from 550°C to 1350°C and were subsequently quickly cooled. The specimens, together with the base material, were then subjected to tensile testing, impact testing, and micro-hardness measurements in the sample cross-section, as well as evaluation of their microstructure. Fracture surfaces are investigated in samples after impact testing. The heat-affected sub-zones studied indicate high sensitivity to the thermal input of welding. There is a significant decrease in tensile strength and yield strength at temperatures around 550°C.

Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of foundry defects in steel castings also meets the requirements for the approval of welding procedures in accordance with the relevant valid legislation.

The goal of this article is non-destructive ultrasonic testing of internal castings defects. Our task was to cast several samples with defects like porosity and cavities (where belongs mostly shrinkages) and then pass these samples under ultrasonic testing. The characteristics of ultrasonic control of castings are presented in the theoretical part of this article. Ultrasonic control is a volume non-destructive method that can detect internal defects in controlled materials without damaging the construction. It is one of the most widely used methods of volume non-destructive testing. For experimental control were made several cylindrical samples from ferritic grey and ductile cast iron. Because of the form and dispersion of graphite of grey cast iron it was not possible to make ultrasonic records on this casting with probe we used, so we worked only with ductile cast iron. Ultrasonic records of casting control are shown and described in the experimental part. The evaluation of the measurement results and the reliability of the ultrasonic method in castings control is listed at the end of this article.

The welding technologies are widely used for design of protection layer against wear and corrosion. Hardfacing, which is destined for

obtaining coatings with high hardness, takes special place in these technologies. One of the most effective way of hardfacing is using self

shielded flux cored arc welding (FCAW-S). Chemical composition obtained in flux cored wire is much more rich in comparison to this

obtained in solid wire. The filling in flux cored wires can be enriched for example with the mixture of hard particles or phases with

specified ratio, which is not possible for solid wires. This is the reason why flux cored wires give various possibilities of application of this

kind of filler material for improving surface in mining industry, processing of minerals, energetic etc. In the present paper the high

chromium and niobium flux cored wire was used for hardfacing process with similar heat input. The work presents studies of

microstructures of obtained coatings and hardness and geometric properties of them. The structural studies were made with using optical

microscopy and X- ray diffraction that allowed for identification of carbides and other phases obtained in the structures of deposited

materials. Investigated samples exhibit differences in coating structures made with the same heat input 4,08 kJ/mm. There are differences

in size, shape and distribution of primary and eutectic carbides in structure. These differences cause significant changes in hardness of

investigated coatings.

The paper presents the capabilities of welding techniques to creating properties of wear resistant high chromium cast iron alloy. The use

of the right kind of welding sequence allows you to change the structure and properties of the obtained welds. Tests were conducted for

one type of additive material in the form of self shielded core wire. In order to determine the effect of the type of welding sequence on the

properties of welds performed welding using string bead and weave bead. The resulting weld was tested on hardness and research structure

in an optical microscope. In the following studies have been made erosive tests wear of made hardfacing. String beads gave structure rich

in carbides and harder about 270 HV of the weld with weave bead. Also, wear resistance was nearly twice as better for welds made with

string beads. In the experiment a decisive role in the resistance to wear plays a high hardness of the deposit and the presence of carbides in

its structure. Changes in the basic parameters of the deposition process allows for the formation of structure and properties of hardfacing

welds in a wide range.

Materials based on cast irons are often used for protection against wear. One of the methods of creating protective surface with cast iron structures is hardfacing. The application of hardfacing with self shielded flux cored wire with high carbon content is one of the economical ways often used to protect machinery parts exposed to both abrasion and erosion. The wear resistance of hardfacings depends on their chemical composition, structure obtained after hardfacing, parameters of depositing process and specific conditions of wear. As the base material in the investigation the steel grade S235JR was used. The wear behavior mechanism of hardfacings made with one type of self shielded flux cored wire and different process parameters were evaluated in this paper. Structures obtained in deposition process were different in hardness, amount of carbides and resistance to wear with two investigated impingement angles. The erosion tests showed that impingement angle 30° gives lower erosion rate than angle 60°.