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The Influence of the Hot Working Tool Steel Substrate Material on the Element Distribution, Microstructure and Hardness of Gas Metal Arc Welding Hardfaced Layers

Lachowicz Marzena M., Sokołowski Paweł, Kaszuba Marcin

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 1

320--333

EN

The paper presents the results of Gas Metal Arc Welding (GMAW) hardfacing testing performed on three grades of hot working tool steels, namely: 55NiCrMoV7, X37CrMoV5-1 and modified X38CrMoV5-3 grade. Metallographic investigations, mainly microstructural ones, were carried out and hardness profiles were analyzed. The chemical composition was investigated in each individual layer of the hardfaced deposits and the substrate material, in order to obtain a profile representation. The obtained results of profilometric evaluation of the chemical composition showed clear differences in the content of basic and alloying elements in the subsequent weld layers. The diversity of the chemical composition of the substrate material caused that the uniform chemical composition for all tested materials was achieved only in the third, upper weld layer. Despite the variable content of alloying elements and carbon, as well as slight differences in microstructure occurring for individual weld layers, a substantially stable and high hardness was maintained over the entire cross-section of the obtained hardfaced coatings. In the area of the heat-affected zone (HAZ), a decrease in hardness was observed, which is associated with the decomposition of the high-temperature tempered martensite and the spheroidization of the microstructure.

2

Nitriding of hardfaced layers as a method of improving wear resistance of hot forging tools

Widomski Paweł, Kaszuba Marcin, Sokołowski Paweł, Lange Artur, Walczak Mariusz, Długozima Marcin, Gierek Mateusz, Chocyk Dariusz, Gładyszewski Grzegorz, Boryczko Bożena

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. e241, 1--16

EN

The article deals with novel hybrid layers combining hard facing and nitriding to improve forging tool durability. It includes a study of the nitriding capabilities of hard facings made of typical materials used to repair key groups of hot forging tools. Tests were conducted on samples and on tools in forging processes. Tests on samples included hard facing, nitriding, microstructure, micro hardness, XRF phase analysis and abrasive wear tests. Experimental tests on forging tools included operational tests and comprehensive wear analysis by scanning, macroscopic and microscopic observations by light and scanning microscopy, and analysis of wear mechanisms. Tests on the samples confirmed the positive effect of nitriding on performance properties at room and elevated temperatures. They revealed the reduced susceptibility to nitriding of some welds and the variable composition of nitrides present on the surface of the samples, which has a key effect on the observed wear mechanisms in the ball-on-disc test. Operational tests showed the effect of improved durability, which is greatest for the DO*15 (Fe–Cr– Mo–W)+nitriding layer which is due to the increased hardness of the weld itself and the increased susceptibility to nitriding.

3

Investigating the Possibility of Regenearation by Hardfacing for Forging Tools Based on Analysis of Tool Working Conditions and Wear Evaluationy

Widomski Paweł, Kaszuba Marcin, Krawczyk Jakub, Nowak Bartłomiej, Lange Artur, Sokołowski Paweł, Gronostajski Zbigniew

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1395--1410

EN

Tests were performed on example tools applied in hot die forging processes. After withdrawal from service due to excessive wear, these tools can be regenerated for re-use through machining and hardfacing. First, analysis of worn tools was carried out for the purpose of identifying tool working conditions and wear mechanisms occurring in the surface layer of tools during forging. Testing of worn tools included observations under a microscope, surface scanning and microhardness measurement in the surface layer. The results indicate very diverse work conditions, which suggest the application of different materials and hardfacing tool regeneration technology in individual die forging processes.

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The application of a new, innovative, hybrid technology combining hardfacing and nitriding to increase the durability of forging tools

Kaszuba Marcin

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

354--366

EN

The article deals with the wear of forging tools used in hot forging processes. The research presented in the work includes analysis of tool life used in a selected industrial hot die forging process. Multiple treatment variants were used to increase wear resistance, including thermo-chemical treatment (nitriding), welding methods (surfacing) and an innovative new hybrid technology combining surfacing and nitriding. First of all, the research focused on determining the impact of the phase structure of the nitrided layers used and the surfacing layer on resistance to destructive factors occurring in the analyzed process. Next, hybrid treated tools combining surfacing and nitriding were also subjected to operational tests. Each of the tools analyzed in this work was operated until it was withdrawn due to excessive wear, and then subjected to comprehensive analysis. The tests of tools after operation included: surface scanning to determine the amount of wear of the analyzed tools after work, microhardness measurement, and microscopic tests. A detailed analysis of changes in the surface layer of tools in selected areas was made using a scanning microscope. The aim of the study was to assess the effectiveness of the hybrid surface treatment process used to increase the wear resistance of the surface layer of tools and thereby improve the durability of the forged tools analyzed. The obtained research results indicate a beneficial effect of using the new technology resulting in 300% increase in the durability of the analyzed tools. The effect of improving durability confirmed by obtained results arises from the use of hybrid layers, which are more resistant to abrasive wear and to cracking due to thermo-mechanical fatigue. Moreover, the study shows that nitriding may have a beneficial influence on improving the lifetime of forging tools, under the condition that the nitrided layer has an α diffusive layer structure, without a larger amount of γ’ and ε nitride precipitates.

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Properties of new-generation hybrid layers combining hardfacing and nitriding dedicated to improvement in forging tools’ durability

Kaszuba Marcin, Widomski Paweł, Białucki Piotr, Lange Artur, Boryczko Bożena, Walczak Mariusz

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

212--223

EN

This article deals with the subject of layers produced in a hybrid process combining hardfacing and nitriding. These layers are characterized by improved resistance to wear, which arises from the synergy between favorable materials during hardfacing and nitriding treatment. Tests were conducted on hot-work tool steel (H11) samples. Hardfaced layers consisting of three layers were applied to these samples, where layers were made from two materials-Robotool 46 and Hardface VMolc powder wires. Next, samples of both materials were nitrided using ZeroFlow gas nitriding technology, with control of potential aimed at obtaining a diffusion layer without a white zone of nitrides on the surface. The next step was to investigate the properties of hardfaced layers and of layers hardfaced after nitriding treatment. Conducted tests covered observations of the microstructure, microhardness measurements as a function of distance from the surface, measurement of stresses in the surface layer by means of X-ray diffraction, and tribological tests. Obtained test results show that hybrid layers combining hardfacing and nitriding may be suitable for improving the lifetime of tools applied in hot forging processes.

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The laboratory tests of hybrid layers combining hardfacing and nitriding dedicated to increase the durability of forging tools in hot forging processes

Widomski Paweł, Gronostajski Zbigniew, Kaszuba Marcin, Kowalska Jagoda, Pawełczyk Mariusz

Welding Technology Review

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2019

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R. 91, nr 2

1--6

EN

In response to the growing need to use wear-resistant layers that increase durability of tools in forging processes, hybrid layers have been proposed that combine hardfacing with nitriding treatment. This article presents the results of laboratory tests of surface wear-resistant layers made with a new hybrid technology Gas-Shielded Metal Arc surfacing (hardfacing) with ZeroFlow gas nitriding. Specimens made with hardfacing or nitriding were prepared and examined. Analysis covered the thorough microstructure study, EDX chemical composition analysis and microhardness analysis. In experiment, 3 different types of nitrided layers were proposed for alpha, gamma prim and epsilon nitrides in the surface layer. The results of metallographic research in the surface layer was presented. The analysis of chemical composition in the particular overlay welds was performed to determine the content of alloying elements in the particular overlay welds. The susceptibility to nitriding of used weld materials as well as the ability to form particular types of nitrides on selected welded substrates was also tested.

PL

W odpowiedzi na narastające potrzeby stosowania warstw odpornych na zużycie, zwiększających trwałość narzędzi w procesach kucia, zaproponowano warstwy hybrydowe łączące napawanie z późniejszą obróbką azotowaniem. W tym artykule przedstawiono wyniki badań laboratoryjnych warstw odpornych na zużycie wykonanych w nowej technologii hybrydowej łączącej napawanie łukowe z azotowaniem gazowym metodą ZeroFlow. Referencyjne próbki wykonane w technologii napawania lub azotowania zostały także przygotowane i zbadane. Analiza obejmowała analizę mikrostruktury, analizę składu chemicznego EDX i analizę mikrotwardości. W ramach eksperymentu zaproponowano 3 różne typy warstw azotowanych na strefę azotków alfa, gamma prim i epsilon w warstwie wierzchniej. Zaprezentowano wyniki badań metalograficznych oraz analizy składu chemicznego w przekroju napoiny. Na tej podstawie określono udział pierwiastków stopowych w poszczególnych warstwach napoiny. Badano również podatność na azotowanie stosowanych napoin a także zdolność do tworzenia się poszczególnych rodzajów azotków na wybranych napawanych podłożach.

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Degradation mechanisms of the burrs in rotablation

Gronostajski Zbigniew, Kaszuba Marcin, Zimoch Wojciech, Reczuch Krzysztof

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1381--1389

EN

Rotablation is a percuteneous coronary procedure dedicated for treatment of highly calcified or fibrotic coronary lesions. This procedure allows plaque modification using a diamond coated burr rotating at high speed. The literature lacks information on the principles for selection of the tools for such a process which would ensure the best efficiency (speed of removing the calcified or fibrotic plaques). The starting point for this is the knowledge of the wear mechanisms in the case of such tools. The present study examines 7 burrs after different operation times. The following mechanisms were considered: pulling out, spalling, abrasion and diamond grains sticking. Based on the performed investigations, it was established that the basic wear mechanism is progressive sticking of the atherosclerotic plaques onto the burrs. In the first place, the burr's front becomes stuck over, yet this should still not have an effect on the speed of the atherosclerotic plaque removal also scarce sticking on the side surface of the burr is observed. During further operation, successive plagues are stuck onto the ones stuck earlier, causing a reduction of the speed of their removal and the necessity of the use of a new burr in order to continue the rotablation.