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.

From the point of welding procedure evaluation, it is important to analyse welds for their impact toughness and transition temperature for three main zones: weld metal, heat-affected zone and base metal. This paper covers butt welds of two QT steel grades, 690 and 890, with thicknesses of 30 mm and 20 mm, respectively. They are interesting regarding yield strength and characteristic weld zones. Basic details of GMAW process used in experiment are provided, with temperatures for impact toughness tests of weld zones varied from +20 °C down to -60 °C. Based on acquired experimental results of impact toughness, fitting curves were developed by use of Oldfield model, i.e. hyperbolic tangent function. Acquired transition temperatures (TT) from fitting curves show mostly allowable values for all three weld zones. As expected, lower strength grade 690 possess higher impact toughness, in comparison to higher strength grade 890. The standardized criteria of minimal absorbed energy of 30 J (KV) and 50% of shear fracture (SF) show different transition temperatures (TT-30J and TT-50%SF), while general dependence of impact toughness to shear fracture (KV vs. SF) shows a reasonable trend. Finally, used GMAW procedures may be considered as acceptable, since for both steel grades (690 and 890) all three weld zones show better TT-30J values than minimal required by standard (TT-30J=-40 °C) for QT structural steels.

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.

Additive manufacturing is technology that is widely used to produce good quality products with complex geometries. One of the most popular additive technology today is fused deposition modelling (FDM). Literature review is showing that many parameters have influence on mechanical properties of FDM printed materials. Influence of FDM 3D printer model on strength properties of printed PLA (polylactic acid) material with different infill density is presented in this paper. Testing specimens are printed with five different 3D printer models of the same manufacturer with the same material and 3D printing parameters. Aim was to investigate 3D printer model influence on strength properties of 3D printed PLA material. The results of this study could be useful for users and researchers in order to select appropriate printer model for particular purpose considering optimal relation of PLA material strength properties and FDM 3D printer model.

Existence of standardized materials and product standards for various products gives confidence in complete material selection process. In case of welded steel products, respective product standards clearly define requirements for design and fabrication. Among many properties, four are mostly considered: strength, ductility, toughness, and weldability. Nowadays products are more demanding than ever, and it is not possible to consider single property anymore, but two or even three of them. In such cases, selection charts are used, making material selection easier. This paper provides selection charts and corresponding design criteria defined in welded product standards for selected structural steel grades. Values presented in selection charts are acquired through own researches, as well as from available literature. Considered structural steels are grades with yield strength from 355 to 960 MPa, available in three mayor delivery conditions: normalized, thermo-mechanically treated, and quenched and tempered.