Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ånmark, Niclas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Inclusion Characteristics and Their Link to Tool wear in Metal Cutting of Clean Steels Suitable for Automotive Applications2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers some aspects of hard part turning of carburised steels using a poly‑crystalline cubic boron nitride (PCBN) cutting tool during fine machining. The emphasis is on the influence of the steel cleanliness and the characteristics of non‑metallic inclusions in the workpiece on the active wear mechanisms of the cutting tool. Four carburising steel grades suitable for automotive applications were included, including one that was Ca‑treated.

    A superior tool life was obtained when turning the Ca-treated steel. The superior machinability is associated with the deposition of lubricating (Mn,Ca)S and (CaO)x-Al2O3-S slag layers, which are formed on the rake face of the cutting tool during machining. Moreover, the transfer of work material to the rake face crater is characteristic in hard part turning of clean steels. It can be because of the lack of sulfides that protect the cutting edge when turning machinability treated steels. This corresponds to the more pronounced crater wear caused by the low‑sulfur steels than that of the steels with higher sulfur contents. It was also concluded that the composition of the non‑metallic inclusions in the Ca‑treated steel is a more important factor than the inclusion number and size, in hard part turning using a PCBN cutting tool. Also, a 3D analysis after electrolytic extraction was found to give a more precise characterisation of non‑metallic inclusions than the conventional 2D analysis by SEM‑EDS. In turn, better correlations to machinability and mechanical properties can be obtained. Hence, the use of this technique is beneficial for future material development.

    Finally, the challenge for future metallurgy is to manufacture high‑performance steels with improved combined properties of mechanical strength and machinability.

  • 2.
    Ånmark, Niclas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Steel characteristics and their link to chip breaking and tool wear in metal cutting2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The vision of this thesis is to study how it is possible to obtain optimised workpieces during metal cutting processes in industry. Specifically, the work is aimed to increase the understanding between the steel characteristics and their link to the chip breaking and tool wear during metal cutting. The emphasis is on the influence of the cleanliness and the characteristics of non-metallic inclusions in the workpiece on the machinability of carburising steel grades. The machinability of a case hardening steel is improved by a M-treatment (additions of Ca). Also, the improved machinability of the M-steels offers an attractive potential to save money which makes it possible to reduce the tooling costs with up to 50%. The improved machinability of Ca-treated steels is correlated to the formation of lubricating slag layers consisting of Ca-enriched sulfide inclusions and oxy-sulfide inclusions, which are formed on the rake face during the machining operation. It is proposed that the formations of slag layers from the workpiece constituents are essential to minimise the chemical degradation of the tool edge due to a contact with the chip. During this process, sulfur minimises the material transfer from the chip flow, whilst Ca-treated impurities have a stabilising effect on the protective deposits made of slag layers.

    Since there is a remaining industrial need to increase the production rate, whilst maintaining a high quality of the finished parts, the future production will continue to require extreme demands on the quality of workpieces. If the emphasis is focused on the workpiece, it should be possible to obtain a robust manufacturing process. Therefore, the challenge for future steel metallurgists is to develop high performance grades with optimised combined properties.

  • 3.
    Ånmark, Niclas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    The influence of microstructure and non-metallic inclusions on the machinability of clean steelsManuscript (preprint) (Other academic)
    Abstract [en]

    This study focused on the evaluation of the machinability of different carburising steel grades by using a cemented carbide cutting tool during semi finishing of steel. The effect of the steel composition, microstructure and inclusion characteristics on the cutting tool wear in the soft part turning was evaluated for a reference steel R (0.028% S, 0.0009% O), a clean C steel (0.003% S, 0.0005% O), and an UC ultra clean steel (0.002% S, 0.0004% O). An improved cutting tool life of about 10-25% was obtained when machining the reference steel R. The favorable machining performance of this steel was attributed to its higher content of non-metallic inclusions, larger grain size and lower micro hardness than that of the clean steels.

  • 4.
    Ånmark, Niclas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Björk, Thomas
    Swerea KIMAB, Kista.
    Steel characteristics and their link to tool wear in hard part turning of transmission componentsManuscript (preprint) (Other academic)
    Abstract [en]

    This study describes the influence of the steel characteristics of Ca-treated carburising steel grades during hard part turning of synchronising rings in gearbox production. The main focus was on the chemical composition of the non-metallic inclusions in the evaluated workpieces and their effect on the PCBN tool wear. In addition, a Ca-treated carburising steel grade was compared to a standard steel grade.

    Machining tests were performed at the transmission machining site at Scania in order to evaluate the PCBN cutting tool life as defined by the generated surface roughness during actual production. The progression of flank and crater wear was evaluated by using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS) and a secondary electron (SE) detector.

    The Ca-treated steel showed a more than doubled tool life than that of the standard steel grade. The superior machinability was linked to the formation of a Ca-enriched slag barrier composed of (Mn,Ca)S and (Ca,Al)(O,S). It is believed that the stability of the protective deposits is essential to minimise diffusion-induced chemical wear of the PCBN tool. Furthermore, the improved machinability corresponds to a reduced tooling cost of 50% during an industrial production of transmission components at the site of Scania. Therefore, to implement the M-steel on a wider range of components would lead to a significantly reduced manufacturing cost per produced component. However, the capability of Ca-treated steels through the complete production route must be further investigated in order to allow for a large scale introduction of Ca-treated steels in the production.

  • 5.
    Ånmark, Niclas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Björk, Thomas
    Swerea KIMAB.
    Ganea, Anna
    Sandvik Coromant.
    Ölund, Patrik
    Ovako Hofors.
    Hogmark, Sture
    Uppsala Unniversitet.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    The effect of inclusion composition on tool wear in hard part turning using PCBN cutting tools2015In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 334, p. 13-22Article in journal (Refereed)
    Abstract [en]

    This work reports on hard part turning of carburizing steels using a PCBN cutting tool in fine machining. Emphasis is on the link between composition of the inclusions in work material and wear mechanisms of the cutting tool. A Ca-treated machinability improved 20NiCrMo steel was included together with three other carburizing steels with different inclusion characteristics.

    Machining tests were conducted to examine cutting tool life and its balance between excessive flank wear or crater wear. The wear mechanisms were examined using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS) and a secondary electron (SE) detector.

    The longest tool life was obtained when cutting the Ca-treated steel. The improved machinability is linked to the deposition of complex (Mn,Ca)S and (Ca,Al)(O,S) protective slag layers that form on the rake face of the cutting tool during machining. Cutting in this steel also resulted in a typical ridge formation in the tool edge crater. Transfer of workpiece material to the rake face crater is characteristic in hard part turning of steel with high cleanliness. This is suggested to be related to the lack of the sulphides that lubricate conventional machinability treated steels, and that the crater wear of low-sulphur steel is more pronounced than for steels with higher sulphur content.

  • 6.
    Ånmark, Niclas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Björk, Thomas
    Swerea KIMAB.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Effect of Different Inclusions on Mechanical Properties and Machinability of 20NiCrMo Carburizing Steels2015In: The 6th International Congress on the Science and Technology of Steelmaking (ICS2015), Beijing: The Chinese Society for Metals , 2015, p. 805-808Conference paper (Refereed)
    Abstract [en]

    In modern steelmaking, carburizing steels are often used for production of automotive components with elevated levels of toughness and fatigue strength. This study is focused on the link between the characteristics of non-metallic inclusions in the steel and the machinability of the given steel grades. For this purpose, inclusion characteristics (such as composition, number, size, morphology etc.) in steel samples were determined by common two-dimensional (2D) observations of inclusions on polished metal surface of samples as well as by three-dimensional (3D) investigations of inclusions after electrolytic extraction from steel samples. The inclusion characteristics were investigated in the three types of 20NiCrMo carburizing steel grades: Steel A ‑ reference steel (410ppm S) having a common level of mechanical properties and machinability, Steel B ‑ steel grade (having 340ppm S) with an improved machinability due to the Ca-treatment and modification of MnS inclusions and Steel C ‑ clean steel grade (40ppm S) having a small amount of inclusions and a higher fatigue strength. It was found that the number of inclusions in Steel B is smaller than that in Steel A and that the inclusion composition is different. At the same time, the estimated machinability (tool life) of the Ca‑treated steel was superior to that of the reference steel. However, the significant decrease of the number of inclusions in the clean steel (Steel C) resulted in a lower machinability in comparison to the reference steel grade.

  • 7.
    Ånmark, Niclas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy. Swerea KIMAB, Sweden.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    The Effect of Different Non-Metallic Inclusions on the Machinability of Steel2015In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 8, no 2, p. 751-783Article in journal (Refereed)
    Abstract [en]

    Considerable research has been conducted over recent decades on the role of non-metallic inclusions and their link to the machinability of different steels. The present work reviews the mechanisms of steel fractures during different mechanical machining operations and the behavior of various non-metallic inclusions in a cutting zone. More specifically, the effects of composition, size, number and morphology of inclusions on machinability factors (such as cutting tool wear, power consumption, etc.) are discussed and summarized. Finally, some methods for modification of non-metallic inclusions in the liquid steel are considered to obtain a desired balance between mechanical properties and machinability of various steel grades.

  • 8.
    Ånmark, Niclas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Lovquist, Simon
    Vosough, Manouchehr
    Bjork, Thomas
    The Effect of Cleanliness and Micro Hardness on the Machinability of Carburizing Steel Grades Suitable for Automotive Applications2016In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 87, no 4, p. 403-412Article in journal (Refereed)
    Abstract [en]

    This work reports on soft part turning of carburizing steels using cemented carbide (CC) cutting tools. The emphasis is on the influence of the cleanliness and micro hardness on the machinability of carburizing steel grades. A reference steel grade is included in this study together with a clean steel and an ultra-clean steel. Machining tests are conducted to examine the cutting tool life, the balance between the excessive flank or crater wear and the chip formation. The wear mechanisms are examined by using a scanning electron microscope (SEM) equipped with a back-scatter (BS) detector. It is possible to differentiate between the machinability of the clean steel grades, having only a minor difference in the sulfur and oxygen contents. Furthermore, the longest tool life is obtained when machining the reference steel. The superior machinability of the reference steel R is linked to its high content of sulfur. It is believed that MnS inclusions act as stress raisers in the primary shear zone. Hence, this will improve the chip formation process.

1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf