Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

Analyzed was the influence of tribocorrosion wear due to effects of fatty acids present in the processed medium. The analysis was conducted on samples made of two austenitic and two martensitic stainless steels. Austenitic steels were tested in their nitrided state and martensitic in their induction hardened state. Conducted were laboratory tests of corrosion resistance of samples, analysis of the microstructure and hardness. To see how the applied processes for modifying the surface of stainless steels behave in realistic conditions, it was conducted the examination of samples/parts of a sunflower cake chain conveyer. Based on the comparison of results obtained in the laboratory and in real conditions, it was estimated that steels AISI 420 and AISI 431 with induction hardened surfaces have a satisfactory resistance to abrasive-adhesive wear in the presence of fatty acids

Recyclability and ecological-economic analysis of a simple photovoltaic panel

Photovoltaic industry has displayed an exponential expansion rate over the past two decades. Currently, 1185 GW of the global electricity demand is derived from photovoltaic (PV) panels with more to come in the next two decades. With the growing installment rate, a concern regarding managing panels that reached the end of their life-span grows. Despite the fact that the approximate life-span of a panel is 25 years, oftentimes this interval is shortened due to weather conditions, low-quality installations, and poor maintenance. Therefore, a global attention is focused on research and law-regulation of proper recycling and disposal of the PV waste. In this contribution, recyclability of one PV panel is determined upon subjecting it to the simplest recycling process, which is manual mechanical separation using common hand-tools. In addition, an ecological-economic analysis of the panel, which yields an absolute profit of the panel is presented

Battery Powered Grass Trimmer Life Cycle Assessment – Case Study

Batteries as a power source are the basis for all major hand tool manufacturers as vide variety of portable products became battery powered for more convenient usage. Manufacturers disable unapproved battery applications in their products by designing batteries specific for these products. In practice, the life of power tool batteries depends on two parameters: natural aging and the type of use. In a case study of a Battery Powered Grass Trimmer which battery broke after four years, the repair procedure for the package is shown. However, shortly after the repair, the Battery Powered Grass Trimmer suffered a bearing deformation that rendered it unusable. Due to its age and the unavailability of replacing electric engine, the Trimmer was scrapped and a detailed Life Cycle Analysis (LCA) applying SimaPro methodology is provided. Since the product under study is no longer on the market, a properly functioning, refurbished battery with significantly increased capacity is used in a new battery-powered grass trimmer from another manufacturer. The paper\u27s final consideration underscores the need for an international standard that regulates battery compatibility and reduces waste, especially electronic waste

VERSCHLIESSFESTIGKEIT DER MARTENSITISCHEN NICHTROSTENDEN STÄHLE MIT OBERFLÄCHENMODIFIKATION FÜR BESSERE KORROSIONS- UND VERSCHLEISSEIGENSCHAFTEN

Na uzorcima korozijski postojanih čelika provedena su laboratorijska ispitivanja te ispitivanja u stvarnim uvjetima trošenja. Elektrokemijska ispitivanja provedena su radi provjere korozijske otpornosti modifi ciranih površina čelika. Na uzorcima korozijski postojanih čelika X20Cr13 i X17CrNi16-2 provedena je metalografska analiza i ispitivanje tvrdoće. Mogućnost primjene modifi ciranih površina na odabranim čelicima provjerena je ispitivanjem uzoraka svornjaka u stvarnim uvjetima trošenja. Uzorci svornjaka zavareni su REL postupkom, a korištena je elektroda Cr-Ni-Mn (18/8/6/). Dobiveni rezultati pokazuju da su indukcijski zakaljeni i naknadno nitrirani martenzitni čelici prosječno postigli otpornost trošenju do tri reda veličine veću u odnosu na dostavno stanje.On test samples of stainless steels, there were conducted laboratory tests and also sample tests in real wear conditions. Electrochemical testings were made towards control of corrosion resistance of modifi ed steel surfaces. On test samples of stainless steels X20Cr13 i X17CrNi16-2, there were conducted metallographic analysis and hardness testing. The possibility of applying modifi ed surfaces of selected steels was cntroled by sample testings in real wear conditions. Test bolts are welded with MMA procedure and it was used electrode Cr-Ni- Mn (18/8/6). Obtained results showed that induction hardened and post-nitrided martensitic stainless steels achieveed for three orders of magnitude bigger wear resistance in relation to asreceived condition.An den Proben der nichtrostenden Stähle wurden laboratorische Prüfungen durchgeführt in den realen Verschleiß Gegebenheiten. Elektrochemische Prüfungen wurden durchgeführt mit dem Ziel der Kontrolle der Korrosionsbeständigkeit bei Stählen mit modifi zierter Oberfl ächenstruktur. An Proben der nichtrostenden Stähle X20Cr13 und X17CrNi16-2, wurden metalographische Analysen und Härtemessungen durchgeführt. Eine Möglichkeit der Anwendung dieser Oberfl ächenmodifi zierten Stähle wurde an Bolzen in realen Verschleiß Gegebenheiten geprüft. Diese Bolzen wurden mit E-Hand und der Cr-Ni-Mn (18/8/6) Elektrode geschweißt. Die Resultate haben darauf eingewiesen dass die induktionsgehärteten und nachträglich nitrierende martensitischen Stähle im durchschnitt eine dreifach bessere Verschleißfestigkeit im Gegensatz zu den Stählen im gelieferten Zustand hatten

Utjecaj parametara kaljenja čeličnog lijeva GS30Mn5 na svojstva utora užnica broda jaružara

Dredgers are special sea floating vessels used for removing sea bottom material in order to: reshape harbor underwater areas and waterways, assembling pipelines, preparing sand beaches and coasts to handle with erosion impact, oil resources exploitation, forming man-made islands… This paper is based on selection of heat treatment parameters of sheaves, surface errors determination method and surface damages recovery. Om test samples made out of same material (GS30Mn5) built—up welding test was carried out of (SMAW procedure) by fluting prepared damage area. Next step was induction hardening using various parameters. Determination of cracks appearance was done by magnet method. By recording cross section structure as well as hardness measuring it has been determined that besides certain level of energy input (electrical current frequency) surface layer properties of sheave edge depend also about choosing proper cooling medium. Satisfying hardness values (320400 HB) were achieved combining air and water cooling simultaneously with avoiding cracks appearance. Parameters selected that way should ensure long working period of ropes (hardness 500550 HB) as well as safe dredgers performance.Jaružari su specijalna morska plovila kojima se materijal s morskog dna uklanja u cilju: oblikovanja - produbljivanja lučnih pristaništa i plovnih puteva, polaganja cjevovoda, održavanja pješčanih plaža i obale od erozije, exploatacije naftnih izvora, formiranja umjetnih otoka nasipavanjem pijeska… Na ispitnim uzorcima izrađenim od istog materijala kao i užnice (GS30Mn5) izvršene su probe navarivanja (REL postupkom). Nakon toga izvršeno je indukcijsko kaljenje, različitim parametrima. Kontrola pojave pukotina utvrđivana je magnetskom metodom. Snimanjem strukture poprečnog presjeka i mjerenjem tvrdoće utvrđeno je da osim o odgovarajućem unosu energije (frekvencija struje) svojstva površinskog sloja utora užnice ovise i o izboru sredstva za hlađenje. Zadovoljavajuće tvrdoće (320÷400 HB) postižu se kombinacijom hlađenja zrakom i vodom uz istovremeno izbjegavanje pojave pukotina. Takav izbor parametara treba da omogući zadovoljavajući vijek užadi (tvrdoće 500550 HB) te pouzdanu exploataciju jaružara

Poboljšanje triboloških svojstava martenzitnih korozijski postojanih čelika

U cilju utvrđivanja mogućnosti povećanja otpornosti tribokorozijskom trošenju martenzitnih korozijski postojanih čelika kao i specifičnih svojstava tribosustava, provedena su istraživanja koja su podijeljena na laboratorijska ispitivanja uzoraka i na ispitivanja uzoraka/dijelova u realanim uvjetima. Napravljena su elektrokemijska ispitivanja koja su za cilj imala usporedbu korozijske otpornosti modificiranih površina martenzitnih i austenitnih korozijski postojanih čelika. Preostala ispitivanja provedena su na uzorcima odabranih martenzitnih čelika AISI 420 i 431. Metalografskim ispitivanjima analizirano je stanje mikrostrukture, a ispitivanjem tvrdoća utvrđene su efektivne dubine indukcijskog kaljenja i nitriranja. Mogućnost primjene modificiranih površina odabranih martenzitnih čelika u realnim uvjetima, provedeno je ispitivanjem uzoraka/dijelova na lančastom transporteru. Dobiveni rezultati potvrđuju da se primjenjenim postupcima zaštite površina ispitivanih uzoraka postigla prosječno za dva reda veličine veća otpornost tribokorozijskom trošenju u odnosu na dostavno stanje

Research on the Effect of Load and Rotation Speed on Resistance to Combined Wear of Stainless Steels Using ANOVA Analysis

This research was carried out with the aim of obtaining appropriate principles for describing the influence of working parameters and the aggressive action of an acidic medium on the wear and corrosion resistance of martensitic stainless steels. Tribological tests were performed on induction-hardened surfaces of stainless steels X20Cr13 and X17CrNi16-2 under combined wear conditions at a load of 100 to 300 N and a rotation speed of 382 to 754 min−1. The wear test was carried out on a tribometer with the use of an aggressive medium in the chamber. After each wear cycle on the tribometer, the samples were exposed to corrosion action in a corrosion test bath. Analysis of variance revealed a significant influence of rotation speed and load due to wear on the tribometer. Testing the difference in the mass loss values of the samples due to corrosion using the Mann–Whitney U test did not show a significant effect of corrosion. Steel X20Cr13 showed greater resistance to combined wear, which had a 27% lower wear intensity compared to steel X17CrNi16-2. The increase in wear resistance of X20Cr13 steel can be attributed to the higher surface hardness achieved and the effective depth of hardening. The mentioned resistance is the result of the creation of a martensitic surface layer with dispersed carbides, which increases the resistance to abrasion, dynamic durability, and fatigue of the surface of the protective layer