Analyses based on FEM calculations have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. Such an approach to design enables obtaining significant savings in production preparation and post-weld deformation corrections and is also important for utility properties of welded joints obtained. As a result, it is possible to make changes to a simulated process before introducing them into real production as well as to test various variants of a given solution. Numerical simulations require the combination of problems of thermal, mechanical and metallurgical analysis. The study presented involved the SYSWELD software-based analysis of GMA welded multipass butt joints made of duplex steel sheets. The analysis of the distribution of stresses and displacements were carried out for typical welding procedure as during real welding tests.

The results of examinations of microstructure and an analysis of its impact on selected mechanical properties of austempered ductile iron (ADI) were presented in the paper. The ADI was produced from the ductile iron containing 1.56% Ni only alloying addition. The effect of the austempering time and temperature on the microstructure and mechanical properties of the examined cast iron was considered. Constant conditions of austenitizing were assumed and six variants of the austempering treatment were adopted. The studyof mechanical properties included a static tensile test, Charpy impact strength test and Brinellhardness measurement.This work complements the knowledge about alloying additions effect on microstructure and mechanical properties of ADI and focuses on the impact of a single alloying element (Ni).

WYKRESY CTP c ŻELIWA SFEROIDALNEGO Z WĘGLIKAMIThis work presents continuous cooling transformation diagrams for different kinds of carbidic nodular cast iron. We investigated the cast iron, chemical composition of which in nodular cast iron allows the obtainment of a metal matrix which consists of: pearlite, upper bainite and its mixture with lower bainite, ausferrite and martensite when the casts were cooled in the mold. The influence of the rate of cooling on the obtained microstructure and hardness of the casts was shown. The work describes the influence of the alloy additives on the curves of austenite decomposition in the carbidic nodular cast iron. Diagrams were plotted which enable an understanding of the kinetics of the transformations of austenite in carbidic nodular cast iron. The diagrams also indicate the possibility of obtaining pearlite, bainite, martensite and ausferrite with the established chemical composition and the wall thickness of the cast.Keywords: carbidic nodular cast iron, bainite, ausferrite, continuous cooling transformation diagrams W pracy przedstawiono wykresy CTP c różnych rodzajów żeliwa sferoidalnego z węglikami. Zbadano żeliwo o składzie chemicznym zapewniającym uzyskanie w żeliwie sferoidalnym osnowy metalowej złożonej z: perlitu, bainitu górnego oraz jego mieszaniny z dolnym, ausferrytu i martenzytu przy studzeniu odlewów w formie. Pokazano wpływ szybkości studzenia na uzyskiwaną mikrostrukturę i twardość odlewów. Opisano wpływ dodatków stopowych na krzywe rozpadu austenitu w żeliwie sferoidalnym z węglikami. Opracowane wykresy umożliwią poznanie kinetyki przemian austenitu w żeliwie sferoidalnym z węglikami oraz ocenę możliwości uzyskania perlitu, bainitu, martenzytu i ausferrytu przy zadanym składzie chemicznym oraz grubości ściany odlewu.

The butt welding of 1.4462 (2205) duplex stainless steel plates with thickness of 4 mm under various welding parameters was achieved by Nd:YAG laser type without the use of the filler material. Welding parameters such as welding power (kW) and the focus distance from the joint surface (mm) were changed. The Ar 5.0 protective gas flow and welding speed were the same for all the tests and were 20 L/min and 0.5 m/min, respectively. The weld shape, weld macrostructure, microstructure, strength and hardness, and the content of the ferrite in the weld zone, heat-affected zone, and base metal were emphatically investigated. The test results showed that increase in laser power increases the weld zone area. For the weld samples, a better ferrite/austenite ratio was obtained by focusing the laser beam on the sheet surface. Furthermore, the largest elongation from strength test has been observed for the weld samples made with laser power of 2.0 kW.