The surfacing technologies are used for constitution of protection layer against wear and is destined for obtaining coating with high

hardness. Among many weldings methods currently used to obtain the hard surface layer one of the most effective way of hardfacing is

using flux cored arc welding. This additional material gives more possibilities to make expected hard surface layer.

Chemical composition, property and economic factors obtained in flux cored wire are much richer in comparison to these obtained with

other additional materials. This is the reason why flux cored wires give possibilities of application this kind of material for improving

surface in different sectors of industry.

In the present paper the imperfection in the layers was used for hardfacing process in different situations to show the possible application

in the surface layer. The work presents studies of imperfection of the welds, contains the picture of microstructures, macrostructures and

shows the results of checking by visual and penetrant testing methods.

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 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°.

The main goal of the article is to identify artificially created defects like lack of fusion and incomplete penetration in butt weld joint using non-destructive volumetric methods. These defects are the most serious defects in welds of steel constructions from the safety point of view. For identification, an ultrasonic phased array technique and a conventional X-ray using digital imaging were used. The theoretical part of the article describes the current state of the given issue and provides basic theoretical knowledge about ultrasonic and X-ray welding tests. In the experimental part, the procedure and results of testing butt weld joint are described by both non-destructive methods. The butt weld joint was made from steel S420MC. Each indication obtained by the ultrasonic and x-ray technique is supplemented by the macrostructure of the weld taken from the indication position. The results of the experimental work mentioned in the article point to the possibility and reliability of the identification of melting defects by selected nondestructive methods in terms of their character and orientation.

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.