The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability
The aim of this work is to compare the technological and material properties of CMnCr steels without bismuth, with 0.08 wt. % Bi and 0.12 wt. % Bi. Experimental heats showed that the most advantageous alloying of Bi into the heat was in the ladle, with an efficiency of about 20%. The optimal tempera...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-02-01
|
| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/12/2/301 |
| _version_ | 1797478013519003648 |
|---|---|
| author | Vladislav Kurka Zdeněk Kuboň Ladislav Kander Petr Jonšta Ondřej Kotásek |
| author_facet | Vladislav Kurka Zdeněk Kuboň Ladislav Kander Petr Jonšta Ondřej Kotásek |
| author_sort | Vladislav Kurka |
| collection | DOAJ |
| description | The aim of this work is to compare the technological and material properties of CMnCr steels without bismuth, with 0.08 wt. % Bi and 0.12 wt. % Bi. Experimental heats showed that the most advantageous alloying of Bi into the heat was in the ladle, with an efficiency of about 20%. The optimal temperature range for forming steel was found to be 1160–1050 °C. With increasing Bi content, the formability of steels and plastic properties decreased, while the yield stress and tensile strength increased. Manganese sulfides, aluminum oxides, or oxysulfides, which were segregated both individually and in clusters, were found in the matrix of all tested steels. In steels with Bi, the Bi particles segregate the separately in the form of globules, either as envelopes of elongated MnS or Al<sub>2</sub>O<sub>3</sub> particles segregated in rows. Sulfur dot-shaped segregations in the steel with 0.12 wt. % of Bi and the steel without Bi were essentially uniform over the whole area. For the steel with 0.08 wt. % of Bi, both dot-like and ray-ordered sulfur segregations were observed. The microstructure of all tested steels was ferritic–pearlitic with islands of bainite. Towards the center of the forged bars, variable shape and size of bainite blocks were observed. Machinability tests evaluated by the extend of tool wear showed that the most advantageous was CMnCr steel alloyed with 0.08 wt. % Bi. |
| first_indexed | 2024-03-09T21:26:55Z |
| format | Article |
| id | doaj.art-bd5d45c33db24288bd03a045df247507 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T21:26:55Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-bd5d45c33db24288bd03a045df2475072023-11-23T21:08:11ZengMDPI AGMetals2075-47012022-02-0112230110.3390/met12020301The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good MachinabilityVladislav Kurka0Zdeněk Kuboň1Ladislav Kander2Petr Jonšta3Ondřej Kotásek4MATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava, Czech RepublicMATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava, Czech RepublicMATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava, Czech RepublicMATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava, Czech RepublicMATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava, Czech RepublicThe aim of this work is to compare the technological and material properties of CMnCr steels without bismuth, with 0.08 wt. % Bi and 0.12 wt. % Bi. Experimental heats showed that the most advantageous alloying of Bi into the heat was in the ladle, with an efficiency of about 20%. The optimal temperature range for forming steel was found to be 1160–1050 °C. With increasing Bi content, the formability of steels and plastic properties decreased, while the yield stress and tensile strength increased. Manganese sulfides, aluminum oxides, or oxysulfides, which were segregated both individually and in clusters, were found in the matrix of all tested steels. In steels with Bi, the Bi particles segregate the separately in the form of globules, either as envelopes of elongated MnS or Al<sub>2</sub>O<sub>3</sub> particles segregated in rows. Sulfur dot-shaped segregations in the steel with 0.12 wt. % of Bi and the steel without Bi were essentially uniform over the whole area. For the steel with 0.08 wt. % of Bi, both dot-like and ray-ordered sulfur segregations were observed. The microstructure of all tested steels was ferritic–pearlitic with islands of bainite. Towards the center of the forged bars, variable shape and size of bainite blocks were observed. Machinability tests evaluated by the extend of tool wear showed that the most advantageous was CMnCr steel alloyed with 0.08 wt. % Bi.https://www.mdpi.com/2075-4701/12/2/301low-alloyed automotive steelbismuthsteelmakingforgingmicrostructuremechanical properties |
| spellingShingle | Vladislav Kurka Zdeněk Kuboň Ladislav Kander Petr Jonšta Ondřej Kotásek The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability Metals low-alloyed automotive steel bismuth steelmaking forging microstructure mechanical properties |
| title | The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability |
| title_full | The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability |
| title_fullStr | The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability |
| title_full_unstemmed | The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability |
| title_short | The Effect of Bismuth on Technological and Material Characteristics of Low-Alloyed Automotive Steels with a Good Machinability |
| title_sort | effect of bismuth on technological and material characteristics of low alloyed automotive steels with a good machinability |
| topic | low-alloyed automotive steel bismuth steelmaking forging microstructure mechanical properties |
| url | https://www.mdpi.com/2075-4701/12/2/301 |
| work_keys_str_mv | AT vladislavkurka theeffectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT zdenekkubon theeffectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT ladislavkander theeffectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT petrjonsta theeffectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT ondrejkotasek theeffectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT vladislavkurka effectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT zdenekkubon effectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT ladislavkander effectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT petrjonsta effectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability AT ondrejkotasek effectofbismuthontechnologicalandmaterialcharacteristicsoflowalloyedautomotivesteelswithagoodmachinability |