The aim is to overcome the issues of high-hardness material welding by different additives used to achieve the desired improvements. The research is focused on Hardox 450 steel welding and factors to be considered in order to maintain the required mechanical properties of the weld. The selection of best suited welding materials or additives, including filler metals and shielding gases, are within the important factors to be taken into account. During the welding of Hardox 450 steel, cobalt, nickel, tungsten and titanium additives and cobalt and tungsten mixture additives were used and their influence on the microstructure and mechanical properties of the fusion and heat-affected zones was investigated. The microstructure of the weld zone is related to certain mechanical properties of the weld and heat-affected zone, such as hardness, tensile and bending strength, yield strength, strain at ultimate tensile strength, the Young’s modulus and elongation. Research has shown significant differences in the mentioned parameters depending on specific additives used in the welds. It can be concluded that tungsten, used as an additive, increased the hardness of the heat-affected and fusion zones up to 478 HV; the combined presence of cobalt and tungsten additives improves the strength of the seam up to 744 MPa during tensile; and in the case of bending, nickel, when used as an additive, increased ductility (the bending modulus reached the limit of 94 GPa) and at the same time, decreased the risk of cracking. The obtained results highlight the possibilities for strengthening the welded joint of Hardox 450 steel using different additives or their mixtures. The research conclusions and recommendations aim at improving the quality and mechanical properties of welded Hardox 450 steel joints in various applications.

This article presents the research results of depositing anti-friction coatings (Babbitt) using three different casting methods: static casting, flame soldering, and clad welding. Babbitt alloy coatings deposited with different casting methods are discussed and explained in terms of changes in the coating properties, such as the microstructure, hardness, strength, and chemical composition. The results showed significant differences in the aforementioned properties, depending on the chosen coating deposition method. The results of the tests confirmed the importance of using shielding gas during deposition to ensure the chemical composition of the coating. The analysis revealed that decreases in the amounts of antimony and copper in the Babbitt coating compared with the initial concentrations were influenced by selective evaporation, oxidation, and the coating process parameters associated with different coating methods. To maintain the desired balance of mechanical properties in Babbitt coatings, it is important to control the antimony and copper contents. Clad welding deposition using a non-consumable tungsten electrode and argon shielding gas achieved a chemically stable coating quite close to the initial chemical composition of the Babbitt alloy.

In this study, the effect of the cold plastic deformation of a Bridgman anvil at room temperature on the hardness and wear resistance of X160CrMoV12 steel was investigated by utilizing the hardness test, X-ray diffraction (XRD), abrasive emery wear (AEMW) test, optical examination, and scanning electron microscopy (SEM). Three batches of samples were prepared for the experiment: I—as-hardened, II—after hardening with subsequent tempering at 600 °C for 1.5 h, and III—after hardening with subsequent plastic deformation. The hardening of the samples was performed at three temperatures: 1100 °C, 1150 °C, and 1200 °C. The highest content of retained austenite, as much as 69.02%, was observed during hardening at 1200 °C, while 17.36% and 38.14% were formed at lower temperatures, respectively. After tempering (Batch II), the content of residual austenite decreased proportionally by a factor of about seven for each hardening temperature. The effect of plastic deformation (Batch III) is observed, analyzing the hardness of the samples from the surface to the depth, reaching an average hardened depth of 0.08 mm. To evaluate the wear resistance, the surfaces of the three test batches were subjected to an abrasive emery wear test under a 5 N load. Hardened and plastically deformed samples showed higher wear resistance than hardened and tempered samples. The results confirmed that the optimal hardening temperature to achieve the maximum wear resistance of this steel is 1100 °C.

Microstructure and properties of structural steel layers subjected to overlay welding utilizing materials powder as well as elect of hardness and microstructure on adhesive wear are investigated. Materials powder spread over the Ct3 steel surface or mixed with the AMS1 flux was melted in low carbon wire Cb 08 arc. The powder of alloying elements Cr, Mo, W, Co and Fe-60%V, Fe 70% Mn, B4C, WC-8%Co and of secondary raw materials (glass, grinding wheels, hard metal plates) was used for overlay welding. Depending on the used powder composi tion and heat treatment, alloyed, hard (to 68 HRC) layers, which wear resistance is similar to standard tool steel, are obtained. http://dx.doi.org/10.5755/j01.mech.17.2.340

This study evaluates a material homogeneity criterion (MHC)-based workflow for the spatial characterization of macrohardness variability in tungsten inert gas (TIG) welded AISI 304 stainless-steel joints produced using 308LSi filler metal. Five welded specimens produced under different welding conditions were first evaluated by transverse tensile testing. Two specimens representing contrasting mechanical responses were subsequently selected for identical spatial macrohardness mapping: Specimen 1 exhibited the lowest ultimate tensile strength (610 MPa), 24% elongation, and fracture through the weld region, whereas Specimen 3 exhibited the highest ultimate tensile strength (684 MPa), 41% elongation, and fracture in the base material. For each specimen, 1000 Rockwell macrohardness (HRBW) measurements were obtained along twenty transverse measurement lines spanning the base material (BM), heat-affected zone (HAZ), and fusion zone (FZ). Mean hardness ranges were comparatively similar for Specimens 1 and 3 (92.04–95.70 and 92.00–95.50 HRBW, respectively). Meanwhile, the coefficient of variation (CV) and Weibull homogeneity coefficient (WHC) provided greater discrimination between the two joints. Specimen 1 exhibited CV values of 0.534–1.433% and WHC values of 81.20–216.95, whereas Specimen 3 exhibited CV values of 0.542–1.076% and WHC values of 107.87–214.12. The largest between-specimen difference was observed within the HAZ, where Specimen 1 exhibited substantially greater macrohardness dispersion than Specimen 3. These results show that statistical treatment of repeated macrohardness measurements can reveal spatial differences between welded joints that are less evident from mean-hardness profiles alone. The comparison does not establish a general predictive relationship between hardness dispersion and tensile performance but provides experimental evidence supporting the discriminatory value of spatial CV and WHC mapping for the two investigated contrasting cases. Optical metallography provides complementary qualitative microstructural characterization, while quantitative relationships between microstructural parameters and macrohardness dispersion remain outside the scope of the present study.