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Moghaddam, P. V., Hardell, J., Vuorinen, E., Caballero, F. G., Sourmail, T. & Prakash, B. (2020). Corrigendum to: The role of retained austenite in dry rolling/sliding wear of nanostructured carbide-free bainitic steels, Wear 428–429 (2019) 193 - 204 [Letter to the editor]. Wear, 446-447, Article ID 203072.
Open this publication in new window or tab >>Corrigendum to: The role of retained austenite in dry rolling/sliding wear of nanostructured carbide-free bainitic steels, Wear 428–429 (2019) 193 - 204
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2020 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 446-447, article id 203072Article in journal, Letter (Other academic) Published
Place, publisher, year, edition, pages
Elsevier, 2020
National Category
Other Materials Engineering Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-77919 (URN)10.1016/j.wear.2019.203072 (DOI)000513004300001 ()2-s2.0-85075451518 (Scopus ID)
Note

Godkänd;2020;Nivå 0;2020-03-02 (alebob)

Erratum in: Wear, vol. 428-429, p. 193-204, DOI: 10.1016/j.wear.2019.03.012

Available from: 2020-03-02 Created: 2020-03-02 Last updated: 2020-05-30Bibliographically approved
Moghaddam, P. V., Hardell, J., Vuorinen, E. & Prakash, B. (2020). Dry sliding wear of nanostructured carbide-free bainitic steels: Effect of oxidation-dominated wear. Wear
Open this publication in new window or tab >>Dry sliding wear of nanostructured carbide-free bainitic steels: Effect of oxidation-dominated wear
2020 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577Article in journal (Refereed) Epub ahead of print
Abstract [en]

The microstructure has a profound impact on sliding wear behaviour. This paper aims to understand the effect of carbide-free bainitic microstructure on oxidation-dominated wear in a self-mated dry sliding contact and compare the results with quenched and tempered martensitic microstructure. The results show improved wear resistance of the carbide-free bainitic steel austempered at low temperature. Hence, the retained austenite content of the carbide free bainitic microstructure is not the only indicator of excellent wear resistance. Compared to tempered martensitic microstructure, the carbide-free bainite offers a higher resistance against the formation of brittle white etching layer during the sliding wear. In summary, the formation of a thin and mechanically stable compositional mixed layer on top of the surface together with a hard underlying substrate are the main reasons behind the improved wear performance of carbide-free bainitic steel austempered at low temperature.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Wear, White etching layer, carbide-free bainite, Nanostructured, Retained austenite, Oxidation
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Other Materials Engineering
Research subject
Machine Elements; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-78941 (URN)10.1016/j.wear.2020.203317 (DOI)
Available from: 2020-05-19 Created: 2020-05-19 Last updated: 2020-05-30
Moghaddam, P. V., Hardell, J., Vuorinen, E. & Prakash, B. (2020). Effect of retained austenite on adhesion-dominated wear of nanostructured carbide-free bainitic steel. Tribology International, 150, Article ID 106348.
Open this publication in new window or tab >>Effect of retained austenite on adhesion-dominated wear of nanostructured carbide-free bainitic steel
2020 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 150, article id 106348Article in journal (Refereed) Published
Abstract [en]

Sliding wear performance of carbide-free bainitic steel is significantly affected by microstructure. This investigation is an attempt to find a correlation between microstructure and wear resistance of carbide-free bainitic steel and compare the results with that of a conventional tempered martensitic microstructure. Under predominantly adhesive wear conditions, carbide-free bainitic microstructure with the highest amount of retained austenite offers the best wear resistance. This is mainly attributed to the more pronounced work hardening and TRIP-effect of carbide-free bainitic microstructure austempered at higher temperature. Therefore, higher initial bulk hardness is not the only indicator of wear resistance. Moreover, when both oxidation and adhesion are active, a microstructure with an optimum content of retained austenite and bainitic ferrite shows the highest wear resistance.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
bainite, Carbide-free, Retained austenite, Wear
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Other Materials Engineering
Research subject
Machine Elements; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-78379 (URN)10.1016/j.triboint.2020.106348 (DOI)2-s2.0-85084407341 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-05-26 (alebob)

Available from: 2020-04-07 Created: 2020-04-07 Last updated: 2020-06-03Bibliographically approved
Gebretsadik, D., Hardell, J. & Prakash, B. (2020). Friction and wear characteristics of PA 66 polymer composite/316L stainless steel tribopair in aqueous solution with different salt levels. Tribology International, 141, Article ID 105917.
Open this publication in new window or tab >>Friction and wear characteristics of PA 66 polymer composite/316L stainless steel tribopair in aqueous solution with different salt levels
2020 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 141, article id 105917Article in journal (Refereed) Published
Abstract [en]

Friction and wear behaviour of a PA 66 composite with 25% glass fibre reinforcement sliding against a 316L stainless steel have been investigated using different aqueous solutions under mixed/boundary lubrication. The aqueous solutions used are deionized water, seawater, seawater without group II metal salts, solution of dissolved Group II metal salts and solution of group II metal salts and NaHCO3. Lower friction and wear was obtained when lubricated with seawater. However, when deionized water or salt solutions without group II metal salts is used, increased wear was observed. The lower friction and wear in seawater solution is due to group II metal ions and bicarbonate ions that facilitate formation of the sparingly soluble carbonates that act as a lubricating tribofilm.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Polyamide, Glass fibre, Seawater, Wear
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements; Machine Elements
Identifiers
urn:nbn:se:ltu:diva-75823 (URN)10.1016/j.triboint.2019.105917 (DOI)000505271400033 ()2-s2.0-85071643762 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-10 (johcin)

Available from: 2019-09-03 Created: 2019-09-03 Last updated: 2020-03-04Bibliographically approved
Decrozant-Triquenaux, J. (2020). High Temperature Tribological Behaviour of PVD Coated Tool Steel and Aluminium under Dry and Lubricated Conditions. Friction
Open this publication in new window or tab >>High Temperature Tribological Behaviour of PVD Coated Tool Steel and Aluminium under Dry and Lubricated Conditions
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2020 (English)In: Friction, E-ISSN 2223-7690Article in journal (Refereed) Submitted
Abstract [en]

Aluminium alloys are commonly used as lightweight materials in the automotive industry. This non-ferrous family of metallic alloys offers a high versatility of properties and designs. To reduce weight and improve safety, high strength-to-weight ratio alloys (e.g. 6XXX and 7XXX), are increasingly implemented in vehicles. However, these alloys exhibit low formability and experience considerable springback during cold forming, and are therefore hot formed. During forming, severe adhesion (i.e. galling) of aluminium onto the die surface takes place. This phenomenon has a detrimental effect on the surface properties, geometrical tolerances of the formed parts and maintenance of the dies. The effect of surface engineering as well as lubricant chemistry on galling has not been sufficiently investigated. DLC and CrN PVD coated steel have been studied to reduce aluminium transfer. However, the interaction between lubricants and PVD coatings during hot forming of aluminium alloys is not yet fully understood. The present study thus aims to characterise the high temperature tribological behaviour of selected PVD coatings and lubricants during sliding against aluminium alloy. The objectives are to first select promising lubricant-coating combinations and then to study their tribological response in a high-temperature reciprocating friction and wear tester. Dry and lubricated tests were carried out at 300°C using a commercial polymer lubricant. Tests using DLC, CrN, CrTiN and CrAlN coated tool steel were compared to uncoated tool steel reference tests. The initial and worn test specimen surfaces were analysed with a 3D optical profiler, SEM and EDS as to understand the wear mechanisms. The results showed formation of tribolayers in the contact zone, reducing both friction and wear. The stability of these layers highly depends on both the coatings’ roughness and chemical affinity towards aluminium. The DLC and CrN coatings combined with the polymer lubricant were the most effective in reducing aluminium transfer.

Keywords
high temperature tribology, aluminium, lubrication, PVD coatings, material transfer, adhesion
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-77693 (URN)
Available from: 2020-02-13 Created: 2020-02-13 Last updated: 2020-02-14
Decrozant-Triquenaux, J. (2020). Influence of Lubrication, Tool Steel Composition and Topography on the High Temperature Tribological Behaviour of Aluminium. Friction
Open this publication in new window or tab >>Influence of Lubrication, Tool Steel Composition and Topography on the High Temperature Tribological Behaviour of Aluminium
2020 (English)In: Friction, E-ISSN 2223-7690Article in journal (Refereed) Accepted
Abstract [en]

The use of high strength aluminium alloys, such as 6XXX and 7XXX series, is continuously increasing for automotive applications in view of their good strength-to-weight ratio. Their formability at room temperature is limited and they are thus often formed at high temperatures to enable production of complex geometries. Critical challenges during hot forming of aluminium are the occurrence of severe adhesion and material transfer onto the forming tools. This negatively affects the tool life and the quality of the produced parts. In general, the main mechanisms involved in the occurrence of material transfer of aluminium alloys at high temperature are still not clearly understood. Therefore, this study is focussed on understanding of the friction and wear behaviour during interaction of Al6016 alloy and three different tool steels in as-received and polished state. The tribotests were carried out under dry and lubricated conditions, with two distinct lubricants, using a reciprocating friction and wear tester. The worn surfaces were analysed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed a high dependence of friction and wear behaviour on the tool steel roughness as well as on the stability of the lubricant films. Tribolayers were found to develop in the contact zone and their capacity to improve the tribological behaviour is seen to be drastically impacted by the surface roughness of the tool steel. When the tribolayers failed, severe adhesion took place and led to high and unstable friction as well as material transfer to the tool steel.

Keywords
friction, wear, high temperature tribology, aluminium, lubrication, tribolayer
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-77692 (URN)
Available from: 2020-02-13 Created: 2020-02-13 Last updated: 2020-02-17
Gebretsadik, D., Hardell, J. & Prakash, B. (2019). Embeddability behaviour of some Pb-free engine bearing materials in the presence of abrasive particles in engine oil. Tribology - Materials, Surfaces & Interfaces, 13(1), 39-49
Open this publication in new window or tab >>Embeddability behaviour of some Pb-free engine bearing materials in the presence of abrasive particles in engine oil
2019 (English)In: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 13, no 1, p. 39-49Article in journal (Refereed) Published
Abstract [en]

One of the tribological requirements on engine bearing material is its ability to safely embed contaminant particles onto its surface and minimise damage to both the bearing and crankshaft surfaces. In this work, a journal bearing test rig that operates under constant load has been employed to investigate the embeddability behaviour of selected multi-layered Pb-free engine bearing materials at three different rotational speeds using engine oil contaminated with SiC particles. Experimental results have shown that third-body abrasive wear is influenced by the lubricant film thickness. There was also difference in embeddability of the different materials. Bismuth-based overlay and MoS2 containing polyamide-imide-based overlay-coated materials show higher wear compared to tin-based overlay and a polyamide-imide-based composite overlay-coated material. Steel counter surfaces sliding against bismuth-based overlay and MoS2 containing polyamide-imide-based overlay exhibited higher wear than those sliding against tin-based overlay and polyamide-imide-based composite overlay. 

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Embeddability, third-body abrasive wear, hydrodynamic lubrication, engine bearings, Pb-free
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-72774 (URN)10.1080/17515831.2019.1574452 (DOI)000471166200005 ()
Note

Validerad;2019;Nivå 2;2019-04-12 (oliekm)

Available from: 2019-02-04 Created: 2019-02-04 Last updated: 2019-07-01Bibliographically approved
Mozgovoy, S., Hardell, J. & Prakash, B. (2019). High Temperature Friction and Wear Performance of PVD Coatings under Press Hardening Contact Conditions. Advances in Tribology, 2019, Article ID 4981246.
Open this publication in new window or tab >>High Temperature Friction and Wear Performance of PVD Coatings under Press Hardening Contact Conditions
2019 (English)In: Advances in Tribology, ISSN 1687-5915, E-ISSN 1687-5923, Vol. 2019, article id 4981246Article in journal (Refereed) Published
Abstract [en]

Press hardening is widely employed to produce automotive structural and safety components from advanced high-strength steels. This process depends on friction between the forming tools and the work piece. Wear of the forming tools affects the dimensional accuracy of produced components and reduces their service life. It is therefore desirable to reduce wear of forming tools for press hardening applications. One way to achieve this is by applying hard physical vapour deposited (PVD) coatings on the tool. In this work, the tribological behaviour of PVD coated tool-work piece material pairs has been studied at elevated temperatures in an experimental set-up simulating the tribological conditions in press hardening. Four different PVD coatings deposited on tool steel and uncoated tools as reference were studied during sliding against uncoated and Al-Si coated 22MnB5 steel. Results show that uncoated tools exhibited the lowest coefficient of friction when sliding against uncoated 22MnB5 steel. A CrWN coating initially showed low coefficient of friction but it increased with increasing sliding distance. A TiAlN coating and one of two AlCrN coatings showed similar frictional behaviour when sliding against uncoated 22MnB5 steel. During sliding against uncoated 22MnB5 steel, adhesive wear has been found to be the dominant wear mechanism. Adhesive wear was considerably reduced in the case of hard PVD coated tools in comparison to that of uncoated tools. During sliding against Al-Si coated 22MnB5 steel, no clear advantage in terms of friction behaviour of uncoated or PVD coated tools was observed. However, the transfer of Al-Si coating material from the work piece to the tools was significantly reduced for PVD coated tools. Frictional instabilities in all cases involving Al-Si coated work piece material further confirmed the occurrence of adhesive material transfer.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2019
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-73812 (URN)10.1155/2019/4981246 (DOI)000466291800001 ()2-s2.0-85065224213 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-02 (johcin)

Available from: 2019-05-02 Created: 2019-05-02 Last updated: 2019-06-25Bibliographically approved
Mozgovoy, S., Alik, L., Hardell, J. & Prakash, B. (2019). Material transfer during high temperature sliding of Al-Si coated 22MnB5 steel against PVD coatings with and without aluminium. In: Wear of Materials: . Paper presented at 22nd International Conference on Wear of Materials, April 14-18 2019, Miami, USA (pp. 401-411). Elsevier, 426-427
Open this publication in new window or tab >>Material transfer during high temperature sliding of Al-Si coated 22MnB5 steel against PVD coatings with and without aluminium
2019 (English)In: Wear of Materials, Elsevier, 2019, Vol. 426-427, p. 401-411Conference paper, Published paper (Refereed)
Abstract [en]

Press hardening of Al-Si coated 22MnB5 steel is the dominant technology to enable light weight design in automotive applications. Transfer of the Al-Si coating onto the tool surface occurs during hot forming. This affects process economy and quality of produced components. The reported galling mechanisms are adhesion and compaction of wear debris. Surface engineering of forming tools has been proposed to minimise the transfer of Al-Si coating. Plasma nitriding of tool steel surfaces reduces adhesion but has poor abrasive wear resistance. PVD coatings have generally been found to promote galling due to higher chemical affinity but improve abrasive wear resistance. Most studied PVD coatings are transition metal nitrides containing aluminium. The aim of this study is to investigate the role of aluminium in PVD coatings and its effect on transfer of Al-Si coating material during sliding against coated tool steel at high temperatures. This work has focussed on PVD coatings (AlCrN and CrWN) deposited on plasma nitrided tool steel. Their tribological behaviour was studied using a hot strip-drawing tribometer capable of simulating the conditions prevalent in press hardening. The results showed that PVD coatings containing aluminium induce more material transfer. The material transfer is mainly related to chemical affinity since all coatings were polished to a low surface roughness (Sa =~120 nm) to minimise transfer initiated by surface defects. The hardness of the PVD coatings does not seem to influence the material transfer since the softer coating (CrWN, HV0.05 = ~1850) showed less transfer compared to AlCrN (HV0.05 = ~2100). The CrWN coating showed longer running-in compared to AlCrN due to reduced initial material transfer. Formation of thicker transfer layers governs the steady state friction mechanisms. Material transfer of Fe-Al intermetallic compounds occurs at the initial stages of sliding through direct adhesion to the PVD coating. The layers grow to > 5 µm thickness within a few decimetres of sliding.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Friction, Wear, High temperature, PVD coating, Aluminium
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-73686 (URN)10.1016/j.wear.2018.12.042 (DOI)000464583700043 ()
Conference
22nd International Conference on Wear of Materials, April 14-18 2019, Miami, USA
Available from: 2019-04-17 Created: 2019-04-17 Last updated: 2019-04-30Bibliographically approved
Deng, L., Pelcastre, L., Hardell, J., Prakash, B. & Oldenburg, M. (2019). Numerical investigation of galling in a press hardening experiment with AlSi-coated workpieces. Engineering Failure Analysis, 99, 85-96
Open this publication in new window or tab >>Numerical investigation of galling in a press hardening experiment with AlSi-coated workpieces
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2019 (English)In: Engineering Failure Analysis, ISSN 1350-6307, E-ISSN 1873-1961, Vol. 99, p. 85-96Article in journal (Refereed) Published
Abstract [en]

Press hardened steels are commonly used as a lightweight choice for manufacturing car components because of the high ratio of strength to weight. The use of ultra-high-strength steels for the design of lightweight vehicles contributes to the reduction of emissions of carbon dioxide while maintaining passenger safety. Stamping tools used in press hardening processes suffer harsh contact conditionsin terms of dramatic temperature changes, cyclic loadings, and complex interactions between coatings and oxidation. In mass production, tool wear is an inevitable problem that increases maintenance costs. Severe adhesive wear, also called galling, substantially occurs in the stamping tool used against Al—Si-coated workpieces. The galling that takes place during press hardening not only degrades the production quality but also shortens the service life of the tool. In order to properly arrange tool maintenance and minimize galling through adjusting process parameters, engineers need to know when and where galling occurs, based on modelling of the galling in press hardening simulations. In order to implement a galling simulation for press hardening, a modified Archard wear model is employed in the present study, which is a contact-mechanics-based model. The specific wear rate in the model is calibrated by the quantitative galling measurements of a high-temperature tribometer test. The tribological test is designed to mimic the press hardening conditions, where the correlations between galling and process parameters such as temperature, pressure, and sliding distance are outlined. The galling simulation is implemented in a full-scale press hardening experiment, and the predicted galling is validated in terms of severe galling positions and galling profiles. The galling profile evolution is correlated to variations in the contact conditions. Uncertainties in the numerical model, such as the choice of penalty scaling factor and friction coefficient, are analysed with a parameter study and discussed. This study demonstrates finite element (FE) simulations involving galling prediction in press hardening so as to improve product development and production efficiency.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Contact conditions, High-temperature tribometer, FE simulation, Galling prediction
National Category
Applied Mechanics Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Solid Mechanics; Machine Elements
Identifiers
urn:nbn:se:ltu:diva-73044 (URN)10.1016/j.engfailanal.2019.01.059 (DOI)000464957800008 ()2-s2.0-85061604416 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-27 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-05-02Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1162-4671

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