Effect of titanium powder addition and heat treatment on the grain size in the weld of ferritic stainless steel of the X2CrTiNb18 grade

Improving the strength properties of ferritic stainless steel welds is associated with reducing excessive grain growth. The article presents the research results on the effect of the titanium additive introduced to the weld material during the welding process of X2CrTiNb18 steel and using different temperature ranges of the heat treatment process for the welds obtained. Significant importance of the influence of titanium addition during welding and heat treatment operations on the change of weld morphology, including the reduction of ferrite grain growth and the change of selected mechanical properties of welds (strength, hardness, plasticity), was demonstrated

Effect of titanium powder addition and heat treatment on the grain size in the weld of ferritic stainless steel of the X2CrTiNb18 grade

Improving the strength properties of ferritic stainless steel welds is associated with reducing excessive grain growth. The article presents the research results on the effect of the titanium additive introduced to the weld material during the welding process of X2CrTiNb18 steel and using different temperature ranges of the heat treatment process for the welds obtained. Significant importance of the influence of titanium addition during welding and heat treatment operations on the change of weld morphology, including the reduction of ferrite grain growth and the change of selected mechanical properties of welds (strength, hardness, plasticity), was demonstrated

Application of laser ablation inductively coupled plasma mass spectrometry in determinations of elemental composition of powders

In laser ablation (LA) a very little amount of solid material is transferred to the gas phase followed by its transport to the source of excitation. The coupling of laser ablation with inductively coupled plasma (ICP) and mass analyzer (MS) allows direct determination of elemental composition of solids. In the case of congested solid samples, LA ICPMS makes possible analysis of element distribution in surface and sub-surface domains of a sample. Unfortunately, not all solid substances appear in congested form as sometimes an analyst receives solid samples in a form of powder. The number of papers related to the possibilities of quantitative analysis of disintegrated samples has been increasing during last years. However, direct analysis of powders, such as soils, sediments or dust, is not possible. Thus the initial step in preparation of such samples is their immobilization in support base, which enables analysis of material of interest without changing sample properties. In this article the possibilities of analysis of immobilized powder samples using ablation process are presented. Homogeneity of powder deposition, purity of material and quality of the ablation process are important parameters and may be used as criteria. Correctness of material selection has to be always confirmed with chosen reference materials. The procedure allowing uniform and reproducible immobilisation of bottom sediment as well as a calibration measurement system with the use of external standards with similar matrix as samples are presented

Coiling simulations of medium-Mn sheet steels using dilatometry

PING 2019 is organized with the support of funds for specific university research project SVK1-2019-002.The work presents the results of coiling simulations of two medium manganese steels containing 3 and 5% Mn. The steels were subjected to the heat treatment including an austenitization at 1000°C for 300s and next isothermal holding at temperatures of 750, 700, 650 and 500°C for duration of 5 hours. The results of dilatometric analysis showed that in case of the 3Mn steel the ferritic transformation occured during the isothermal holding at 750 and 700°C. The amount of ferrite created during this step at 750°C was smaller compared to 700°C. Lowering the temperature to 650°C led to a transformation lack during the holding time. At 500°C a bainitic transformation occurred. Increasing the manganese content resulted in prolonging the incubation time before any transformations. For the 5Mn steel for all isothermal holding temperatures no transformation occurred within 5 hours. The conclusion was that manganese shifted significantly the ferritic and bainitic regions to longer times

Influence of silver-containing filler on antibacterial properties of experimental resin composites against Enterococcus faecalis

Purpose: The aim of the presented work was to investigate the impact of the S-P introduction into resin-based composites on their effectiveness against Enterococcus faecalis (E. faecalis). Design/methodology/approach: Seven experimental composites based on typical matrix were developed. Six of them contained a filler with antimicrobial properties (silver sodium hydrogen zirconium phosphate, S-P), while the control material contained only common reinforcement fillers. The materials were characterized in terms of the dispersion of the extender in the matrix and then subjected to microbiological tests. The efficiency in the reduction of E. faecalis in the microenvironment was tested. Findings: The composites show a satisfactory distribution of fillers and a high initial reduction of bacteria colonies for the tested strain of E. faecalis. The reduction in bacteria colonies achieved for S-P concentrations from 7% to 13% was similar (median value from 99.8 to 99.9%, when for control material and compound with 1% S-P the number of colonies increased compared to positive control. Research limitations/implications: Laboratory test results may differ from in vivo test performance. In addition, there are many models for conducting laboratory antimicrobial efficacy studies, the results of which are also varied. The cytotoxic tests, long-term investigations and in vivo experiments need to be performed in future experiments. Practical implications: E. faecalis is a Gram-positive bacterium that is commonly detected in persistent endodontic infections and may enter the root canal through the coronal part. Development of composites with antimicrobial properties against this bacterium is as important as obtaining efficacy against cariogenic bacteria. Originality/value: The antimicrobial effectiveness against E. faecalis of experimental composites with submicrometer-sized particles of S-P was not investigated until now

Selected tribological parameters for silumin alloy used for engine piston

Purpose: The conducted tests were aimed at determining whether the tested material meets the requirements for wear resistance in modern turbocharged combustion engines where there is an increased temperature and higher pressure. Design/methodology/approach: The tests were performed in a pin-on-disc system, according to the ASTM G 99 standard. Findings: The article presents the results of the coefficient of friction, the amount of wear, chemical analysis and surface profile of the tested material A390.0 in combination with EN GJL-350 cast iron. Research limitations/implications: The tested materials are used in the construction of pistons for internal combustion engines, therefore the test parameters were selected to take into account the operating conditions in a turbocharged engine with a power of up to 100 kW. Practical implications: After analysing the properties of the A390.0 alloy at elevated temperatures, it was found that without additional modifications, the alloy cannot be used in modern combustion engines, in particular with turbocharging. Originality/value: Presents the results of research concerning mechanical properties (HB, HV, Rm) and yield properties (R0.2, A5, Z) of the examined alloy

Properties of the Aluminium Alloy EN AC-51100 after Laser Surface Treatment

In this paper, the influence of a laser surface treatment on the structure and properties of aluminium alloy has been determined. The aim of this work was to improve the tribological properties of the surface layer of the EN AC-51100 aluminium alloy by simultaneously melting and feeding silicon carbide particles into the molten pool. The silicon carbide powder was introduced into the liquid metal using a gravity feeder within a constant feed rate of 1 g/min. A high power diode laser (HPDL) was used for remelting. Laser beam energies used in experiments were 1.8 kW, 2.0 kW and 2.2 kW, combined with the constant velocity of 50 mm/min. As a result of the laser treatment on the aluminium alloy, a composite layer with greater hardness and wear resistance compared to the based material was obtained

Influence of Chemical Composition on the Properties of Experimental Silicone-Based Soft Lining Composites

The paper analyses the influence of chemical composition of silicone-based composites on their properties in the aspect of using them as long-term soft denture lining materials. Different concentrations of filler and methylhydrosiloxane-dimethylsiloxane copolymer were used. The filler was introduced into the composite with mechanical mixing combined with ultrasonic homogenization. Scanning electron microscopy was used to investigate the quality of filler dispersion. Shore A hardness, tensile strength, sorption, solubility and tensile bond strength to poly(methyl methacrylate) were measured. Tests show satisfactory results for some experimental composites, which met all the requirements for such materials