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The characteristics of non-metallic inclusions (NMIs) in low-alloyed steel samples taken during ladle treatment before and after Ca-treatment were evaluated by using the Pulse Distribution Analysis Optical Emission Spectroscopy (PDA/OES) method, INCA-Feature investigations of inclusions on a polished surface of steel samples, and three-dimensional investigations of NMIs after electrolytic extraction (EE) of steel samples. The investigation results of NMIs by using different methods were compared. The PDA/OES results show a clear tendency of a change in the average composition and quantity of NMIs during the ladle treatment, which correlated well with the results obtained from the other two methods. Overall, it was found that the application of the PDA/OES method is appropriate to enable a fast online evaluation of inclusion compositions and their behaviors during steelmaking. This, in turn, provides the means for establishing an online control and correction of technological operations of the ladle treatment to implement necessary modification of NMIs in order to improve the cleanliness of steels and to avoid clogging problems during casting.
Hongying Du; Annika Yang; Andrey V. Karasev; Pär G. Jönsson. Characterization of Nonmetallic Inclusions in Low‐Alloyed Steels Using Pulse Distribution Analysis Optical Emission Spectroscopy and Offline Investigation Methods. steel research international 2021, 1 .
AMA StyleHongying Du, Annika Yang, Andrey V. Karasev, Pär G. Jönsson. Characterization of Nonmetallic Inclusions in Low‐Alloyed Steels Using Pulse Distribution Analysis Optical Emission Spectroscopy and Offline Investigation Methods. steel research international. 2021; ():1.
Chicago/Turabian StyleHongying Du; Annika Yang; Andrey V. Karasev; Pär G. Jönsson. 2021. "Characterization of Nonmetallic Inclusions in Low‐Alloyed Steels Using Pulse Distribution Analysis Optical Emission Spectroscopy and Offline Investigation Methods." steel research international , no. : 1.
Currently, the available evaluation methods for determining the chip breakability in the industry are mainly based on subjective visual assessment of the chip formation by an operator during machining or on chips that were collected after the tests. However, in many cases, these methods cannot give us accurate quantitative differences for evaluation of the chip breakability of similar steel grades and similar sets of machining parameters. Thus, more sensitive methods are required to obtain more detailed information. In this study, a new method for the objective assessment of chip breakability based on quantitative determination of the weight distribution of chips (WDC) was tested and applied during machining of stainless steels without Ca treatment (316L) and with Ca treatment (316L + Ca). The obtained results show great consistencies and the reliability of this method. By using the WDC method, significant quantitative differences were obtained by the evaluation of chips, which were collected during the machining process of these two similar grades of steel at various cutting parameters, while, visually, these chips look very similar. More specifically, it was found that the Ca treatment of steel can improve the chip breakability of 316L + Ca steel in 80% of cutting trials, since a fraction of small light chips (Type I) from this steel increased and a fraction of large heavy chips (Type III) decreased accordingly. Moreover, the WDCs that were obtained at different cutting parameters were determined and compared in this study. The obtained results can be used for the optimization of chip breakability of each steel at different cutting parameters. The positive effect of Ca treatment of stainless steel was discussed in this study based on consideration of the modification of different non-metallic inclusions and their effect on the chip breakability during machining.
Hongying Du; Andrey Karasev; Thomas Björk; Simon Lövquist; Pär G. Jönsson. Assessment of Chip Breakability during Turning of Stainless Steels Based on Weight Distributions of Chips. Metals 2020, 10, 675 .
AMA StyleHongying Du, Andrey Karasev, Thomas Björk, Simon Lövquist, Pär G. Jönsson. Assessment of Chip Breakability during Turning of Stainless Steels Based on Weight Distributions of Chips. Metals. 2020; 10 (5):675.
Chicago/Turabian StyleHongying Du; Andrey Karasev; Thomas Björk; Simon Lövquist; Pär G. Jönsson. 2020. "Assessment of Chip Breakability during Turning of Stainless Steels Based on Weight Distributions of Chips." Metals 10, no. 5: 675.
The focus of this study involved comparative investigations of non-metallic inclusions in 316L stainless steel bars without and with Ca treatments. The inclusions were extracted by using electrolytic extraction (EE). After that, the characteristics of the inclusions, such as morphology, size, number, and composition, were investigated by using a scanning electron microscope (SEM) in combination with an energy dispersive X-ray spectroscopy (EDS). The following four types of inclusions were observed in 316L steels: (1) Elongated MnS (Type I), (2) MnS with hard oxide cores (Type II), (3) Undeformed irregular oxides (Type III), and (4) Elongated oxides with a hard oxide core (Type IV). In the reference sample, only a small amount of the Type III oxides (Al2O3–MgO–MnO–TiOx) existed. However, in Ca-treated 316L steel, about 46% of the observed inclusions were oxide inclusions (Types III and IV) correlated to gehlenite and to a mixture of gehlenite and anorthite, which are favorable for the machinability of steel. Furthermore, untransformed oxide cores (Al2O3–MgO–MnO) were also found in the inclusions of Type IV. The mechanism leading to different morphologies of oxide inclusions is also discussed.
Hongying Du; Andrey Karasev; Olle Sundqvist; Pär G. Jönsson. Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi. Metals 2019, 9, 74 .
AMA StyleHongying Du, Andrey Karasev, Olle Sundqvist, Pär G. Jönsson. Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi. Metals. 2019; 9 (1):74.
Chicago/Turabian StyleHongying Du; Andrey Karasev; Olle Sundqvist; Pär G. Jönsson. 2019. "Modification of Non-Metallic Inclusions in Stainless Steel by Addition of CaSi." Metals 9, no. 1: 74.
Nowadays, the existing evaluation methods of chip breakability in industry are based on subjective visual evaluations of the chip formation during cutting or on a chip chart made after the tests. However, more sensitive methods are needed to provide more in-depth information. Thus, this study proposes a method to better evaluate the chip breakability. Based on a systematically study using the weight distribution measurement method, the results show that a great consistency and reliability to evaluate the chip breakability can be obtained. Overall, it is an objective, available and precise method to be applied in the academic and industrial research.
Hongying Du; Andrey Karasev; Nils Stavlid; Thomas Björk; Simon Lövquist; Pär Jönsson. Using chip weight distribution as a method to define chip breakability during machining. Procedia Manufacturing 2018, 25, 309 -315.
AMA StyleHongying Du, Andrey Karasev, Nils Stavlid, Thomas Björk, Simon Lövquist, Pär Jönsson. Using chip weight distribution as a method to define chip breakability during machining. Procedia Manufacturing. 2018; 25 ():309-315.
Chicago/Turabian StyleHongying Du; Andrey Karasev; Nils Stavlid; Thomas Björk; Simon Lövquist; Pär Jönsson. 2018. "Using chip weight distribution as a method to define chip breakability during machining." Procedia Manufacturing 25, no. : 309-315.