RESUMEN
This paper presents the results of tests on the fabrication of welded joints in S1300QL steel according to the requirements of ISO 15614-14 and ISO 12932. The butt-welded joint without bevel was made from 350 × 150 × 8 mm sheets. The welding process was carried out at the hybrid welding (laser-MAG) station. MAG means metal active gas. The test welded joints were subjected to non-destructive and destructive testing. Visual and radiographic examinations were carried out. The distribution of HV10 hardness was determined in the weld, the heat-affected zone, and the base material. The microstructure of these areas was also analysed for the presence of hard and brittle hardening products and non-metallic inclusions. Tensile strength and yield strength, as well as bending strength, were assessed in the mechanical property tests. The impact test was performed in accordance with ISO 9016.
RESUMEN
The article discusses the effect of the hybrid-welding process (laser-electric arc MAG Metal Active Gas) on the structure and properties of butt joints (having various thicknesses, i.e., 5 mm and 7 mm) made of steel S960QL. Welding tests were performed in the flat position (PA) and in the horizontal position (PC). Joints made of steel S960QL in the above-presented configuration are present in elements of crane structures (e.g., telescopic crane jibs). The welding tests involved the use of the G Mn4Ni1.5CrMo solid electrode wire and the Ar+18% CO2 shielding gas mixture (M21) (used in the MAG method). Non-destructive visual and radiographic tests did not reveal the presence of any welding imperfections in the joints. The welded joints obtained in the tests represented quality level B in accordance with the requirements of the ISO 12932 standard. Microscopic metallographic tests revealed that the heat-affected zone (HAZ) contained the coarse-grained martensitic structure resulting from the effect of the complex welding thermal cycle on the microstructure of the joints. Destructive tests revealed that the joints were characterised by tensile strength similar to that of the base material. The hybrid welding (laser-MAG) of steel S960QL enabled the obtainment of joints characterised by favourable plastic properties and impact energy exceeding 27 J. The tests revealed the possibility of making hybrid-welded joints satisfying the quality-related requirements specified in the ISO 15614-14 standard.
RESUMEN
Biocides are commonly applied to construction materials such as facade renders and paints in order to protect them from microbial spoilage. These renders and paints are exposed to weathering conditions, e.g., sunlight and rain. Pigments are interacting intensively with the spectrum of the incoming light; thus, an effect of paint pigments on phototransformation rates and reaction pathways of the biocides is hypothesized. In this study, the phototransformation of four commonly used biocides (carbendazim, diuron, octylisothiazolinone (OIT) and terbutryn) in four different paint formulations differing solely in pigments (red and black iron oxides, white titanium dioxide, and one pigment-free formulation) were investigated. Paints surfaces were irradiated under controlled conditions. The results show that biocides degrade most rapidly in the pigment-free formulation. The degradation in the pigment-free formulation followed a first-order kinetic model with the respective photolysis rate constants: kp,Diuron = 0.0090 h-1, kp,OIT = 0.1205 h-1, kp,Terbutryn = 0.0079 h-1. Carbendazim concentrations did not change significantly. The degradation was considerably lower in the pigment-containing paints. The determination of several phototransformation products of terbutryn and octylisothiazolinone showed different transformation product ratios dependent on the pigment. Consequently, pigments not only reflect the incoming light, but also interact with the biocide photodegradation.
RESUMEN
The use of biocides as additives for building materials has gained importance in the recent years. These biocides are applied, e.g., to renders and paints to prevent them from microbial spoilage. However, these biocides can leach out into the environment. In order to better understand this leaching, the partition of biocides between water and inorganic phases of render with organic binder was investigated. The partition constants of carbendazim, diuron, iodocarb, isoproturon, cybutryn (irgarol), octylisothiazolinone, terbutryn, and tebuconazole towards minerals typically used in renders, e.g. barite, calcium carbonate, marble, kaolinite, and talc were determined. Partition constants for calcium carbonate varied between 0.2mLg-1 (diuron) and 5.2mLg-1 (iodocarb), respectively. The results for barite and kaolinite were in a similar range and usually the compounds with high partition constants for one mineral also had high values for the other mineral. No sorption to marble at all was found. From all minerals investigated, only talc showed high partition for all studied biocides. Partition constants for talc varied from 21.3mLg-1 (iodocarb) to 683.7mLg-1 (tebuconazole), respectively. The comparison with render-water distribution constants of two artificially made renders showed that the distribution constants can be estimated based on partition constants of compounds for individual components of the render.