High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations
Modern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the Heat Affect Zone, the region in which cracks...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-02-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/14/4/936 |
| _version_ | 1797396301592133632 |
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| author | Bożena Szczucka-Lasota Tomasz Węgrzyn Tadeusz Szymczak Adam Jurek |
| author_facet | Bożena Szczucka-Lasota Tomasz Węgrzyn Tadeusz Szymczak Adam Jurek |
| author_sort | Bożena Szczucka-Lasota |
| collection | DOAJ |
| description | Modern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the Heat Affect Zone, the region in which cracks occur. Another disadvantage is connected with differences in values of ultimate strength of parent and weld material. The differences can be diminished using the correct welding process, which employs nickel and molybdenum electrode wires at much lower sulfur content. The weld metal deposit contains mainly martensite and bainite with coarse ferrite, while the parent material contains mainly martensite and rather fine ferrite. New technology, micro-jet cooling after the joining process enables to obtain the microstructure of weld metal deposit at acceptable parameters. Welding with micro-jet cooling could be treated as a very promising welding Docol steels process with high industrial application. Results of non-destructive inspections on macro samples corresponded with further destructive test results (tensile strength, hardness, fatigue, metallographic structure analyses). This article aims to verify fatigue behavior of Docol 1200 M steel after welding supported by the cooling using the micro-jet technique. For the first time, micro-jet cooling was used to weld this kind of steel to check the mechanical properties of the joint, especially to determine the fatigue limit. This study is formulated as follows: investigating fatigue resistance of the Docol 1200 M weld manufactured at the cooling process with micro-jets. The joints were produced in the MAG (Metal Active Gas) technology modified by micro-jet cooling. The results collected in the fatigue test were processed in the form of the Wöhler’s S–N diagram following the fatigue limit of the weld examined. All data have indicated the possibility of obtaining a new method of welded joints with high fatigue limit minimum of 480 MPa. It could be important to achieve a tensile strength of 700 MPa while maintaining the best relative elongation at the level of the base material. |
| first_indexed | 2024-03-09T00:49:20Z |
| format | Article |
| id | doaj.art-2a324de327ae4a3799febc5990d7d249 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T00:49:20Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-2a324de327ae4a3799febc5990d7d2492023-12-11T17:18:43ZengMDPI AGMaterials1996-19442021-02-0114493610.3390/ma14040936High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical InvestigationsBożena Szczucka-Lasota0Tomasz Węgrzyn1Tadeusz Szymczak2Adam Jurek3Faculty of Transport and Aviation Engineering, Silesian University of Technology, Krasińskiego 8, 40-119 Katowice, PolandFaculty of Transport and Aviation Engineering, Silesian University of Technology, Krasińskiego 8, 40-119 Katowice, PolandDepartment of Vehicle Type-Approval & Testing, Motor Transport Institute, ITS, Jagiellońska 80, 03-301 Warsaw, PolandNovar Sp. z o. o., Towarowa 2, 44-100 Gliwice, PolandModern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the Heat Affect Zone, the region in which cracks occur. Another disadvantage is connected with differences in values of ultimate strength of parent and weld material. The differences can be diminished using the correct welding process, which employs nickel and molybdenum electrode wires at much lower sulfur content. The weld metal deposit contains mainly martensite and bainite with coarse ferrite, while the parent material contains mainly martensite and rather fine ferrite. New technology, micro-jet cooling after the joining process enables to obtain the microstructure of weld metal deposit at acceptable parameters. Welding with micro-jet cooling could be treated as a very promising welding Docol steels process with high industrial application. Results of non-destructive inspections on macro samples corresponded with further destructive test results (tensile strength, hardness, fatigue, metallographic structure analyses). This article aims to verify fatigue behavior of Docol 1200 M steel after welding supported by the cooling using the micro-jet technique. For the first time, micro-jet cooling was used to weld this kind of steel to check the mechanical properties of the joint, especially to determine the fatigue limit. This study is formulated as follows: investigating fatigue resistance of the Docol 1200 M weld manufactured at the cooling process with micro-jets. The joints were produced in the MAG (Metal Active Gas) technology modified by micro-jet cooling. The results collected in the fatigue test were processed in the form of the Wöhler’s S–N diagram following the fatigue limit of the weld examined. All data have indicated the possibility of obtaining a new method of welded joints with high fatigue limit minimum of 480 MPa. It could be important to achieve a tensile strength of 700 MPa while maintaining the best relative elongation at the level of the base material.https://www.mdpi.com/1996-1944/14/4/936smart citytransportvehiclesmechanical engineeringDocol steelmicro-jet welding |
| spellingShingle | Bożena Szczucka-Lasota Tomasz Węgrzyn Tadeusz Szymczak Adam Jurek High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations Materials smart city transport vehicles mechanical engineering Docol steel micro-jet welding |
| title | High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations |
| title_full | High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations |
| title_fullStr | High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations |
| title_full_unstemmed | High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations |
| title_short | High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations |
| title_sort | high martensitic steel after welding with micro jet cooling in microstructural and mechanical investigations |
| topic | smart city transport vehicles mechanical engineering Docol steel micro-jet welding |
| url | https://www.mdpi.com/1996-1944/14/4/936 |
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