This paper deals with a sensitivity analysis of engineering critical assessment, using a fracture assessment diagram of through-thickens axial flaws on pressure equipment. Basic option calculations are performed per BS 7910, using engineering fracture mechanics principles, followed by the provision of assessment points. For evaluation purposes, arbitrary design properties of pressure equipment and temperature-dependent materials properties were used. Several through-thickness axial flaw sizes were used for critical assessment. Furthermore, the sensitivity of critical assessment is evaluated by varying stress states and material fracture toughness. Finally, the sensitivity analysis shows how axial flaw growth may become critical, or its acceptability, depending on varying stress states and temperature-dependent material properties, on selected pressure equipment.

One of the most often used welding processes for unalloyed structural steels is MAG, which is relatively simple, yet achieving high deposition rates. On the other side, there are standards describing weld quality based on weld geometry. This paper describes influence of heat input on weld geometry for MAG fillet welds of unalloyed steel with thicknesses of 8 mm, in horizontal and overhead position. Independently varied parameters were welding current and speed. Influence is described through models based on linear regression analysis. Comparison is made between models developed for different positions, as well as with those available in literature.

This paper describes influences of heat input on leg size of pulsed GMAW fillet welds of unalloyed steel with thicknesses of 4 mm, in horizontal and overhead position. Varied parameters were welding current and speed, while voltage and current profile were predefined by welding equipment manufacturer. Influence is described through models based on linear regression analysis. Comparison is made between developed models, as well as with those available in literature.

In GMAW welding, there are several types of metal transfer that are primarily determined by the primary welding parameters. Different metal transfers in an electric arc are characteristic of different applications. In this paper, a detailed characterization of the pulse transfer of metals in an electric arc is performed, including the characterization of parameters and criteria for their selection on the used power source for welding Welbee. For a given Welbee device, the choice of parameters in steel welding is shown, as well as the synergy function that is characteristic of these devices. Welding was performed on structural steels, with previously adopted parameters, accompanied by recording the dynamic characteristics of current and voltage with an oscilloscope. Based on the available literature sources, the existing models for heat input calculation in GMAW pulse welding were analysed in detail. Heat input calculation for welded steel sheets was performed by using one of them, with current and voltage profiles recorded with an oscilloscope. After the experiment, the obtained results were elaborated, and general comments were given regarding influence of parameters on the quality of welded joints.

Abstract This paper describes influences of heat input on geometry of GMAW fillet welds of unalloyed steel with thicknesses of 8 mm. Welding current and speed are varied, as parameters influencing heat input, while weld size, reinforcement, penetration, dilution and weld asymmetry are considered as geometry properties. All of them are obtained through measurements on macro-sections. Influence of heat input on geometry is presented through the model based on regression analysis.

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.

This paper presents principal influences of heat input and welding position on geometrical properties of fillet welds for conventional and pulsed GMAW of unalloyed steel. We took into consideration geometrical properties such as fillet weld size, penetration, dilution and reinforcement. All presented influences are represented by fitting curves, based on simple linear regression of experimental data provided by visual and macro-section examination.

The paper presents results of combined, conventional and non-conventional, approach for evaluation of mechanical and technological properties of structural steel's welded joints. The selected structural steels are in the range of most common used strength level(s), as well as corresponding various chemical composition concept(s) and processing routes. A short review regarding weldability is presented based on recommendation provided in EN 1011-2, manufacturers recommendation, and own results. However, even it is a well-known fact, mismatching of properties is presented rather to provide sense of its level for particular steel grades. Moreover, the level of under-matching of weakest weld zone (coarse grained heat affected zone), provided by mean of welding thermo-cycle simulation is presented. This is due to the fact that such estimation is not possible with everyday conventional (standardized) testing. The most important design and technological properties of welded joint(s) are considered; e.g. strength, ductility, hardness, microstructure and toughness.