When heterogeneous joints are created, problems with the formation of intermetallic phases arise. There are various ways to reduce the formation of intermetallics. One of the ways that is discussed in this article is to use a suitable interlayer of appropriate thickness when forming the joint. A too-thin interlayer does not protect against the formation of brittle intermetallic phases. On the other hand, a too-thick interlayer increases the heterogeneity of the joint and, thus, decreases its useful properties. Within this paper, the formation of diffusion joints between the base material (AISI 304 steel, duplex steel, AISI 316L steel, or titanium grade 2) and the 0.2 mm thick intermediate layer (nickel or vanadium) was studied. Initial diffusion joints were prepared in a Gleeble 3500 machine, and samples for the study of diffusion kinetics were subsequently heat-treated in a vacuum furnace. The result of the research was the determination of specific diffusion parameters of nickel and vanadium into all four tested base materials. The initial diffusion depth (simple heating to the target temperature without holding at this temperature) of nickel was 4.46 µm into duplex steel and 5.48 µm into Ti Gr. 2 at 950 °C. At the same temperature, the initial diffusion depth of vanadium was 14.54 µm into duplex steel and 14.32 µm into Ti Gr. 2. In addition, general equations for the calculation of diffusion coefficients for the mentioned materials in the temperature range of 850 to 1150 °C were established.

The use of high-strength low-alloy (HSLA) steels for welded parts and structural assemblies is becoming increasingly common. Steel S700MC is one of the most widely used HSLA steels, especially in the automotive and manufacturing industries. It combines high-strength properties with good ductility, toughness, and reasonable technological workability in forming and welding. Despite all these advantages, there is still not enough information describing the processes and changes in material properties that occur in different heating and cooling conditions. The present study aims to provide a detailed description of these phenomena through dilatometric tests. The result is primarily an assessment of the effect of thermal cycles on the change in average grain size. Additionally, through the applied dilatometric tests, it was possible to assess the effect of heating rate on the changes in austenitization temperatures. The influence of the cooling rate on the width of the transformation zone was also defined. This is a comprehensive study that has not yet been published for steel S700MC.

This study explores the influence of various conventional cooling media (water, cutting fluid, and quenching oil) on the mechanical properties of FSW joints in AA7075-T61 aluminum alloy. Cooling media had minimal impact on the macrostructure of AA7075-T651 joints, though a slight increase in the...

The use of High-Strength LowAlloy (HSLA) steels for welded parts and structural assemblies is increasingly common. Steel S700MC is one of the most widely used HSLA steels, especially in the automotive and manufacturing industries. It combines high-strength properties with good ductility, toughness and reasonable technological workability in forming and welding. Despite all these advantages, there is still not enough information describing the processes and changes in material properties that occur in different heating and cooling conditions. The present study aims to describe such processes in detail using dilatometric studies. Thus, it results not only in a newly developed Continuous Cooling Transformation (CCT) diagram of the S700MC steel, but also in an assessment of the heating rate effect on the change of austenitizing temperatures. Then, the influence of the cooling rate on the bandwidth of transformation changes is defined, and the impact of temperature cycles on the changes in mean grain size is assessed. A comprehensive study of this type has not yet been published for S700MC steel.