Laser transformation hardening of carbon steel: Microhardness analysis on microstructural phases

F. Qiu (Corresponding Author), J. Uusitalo, Veli Kujanpää

    Research output: Contribution to journalArticleScientificpeer-review

    10 Citations (Scopus)

    Abstract

    This study investigates the microhardness and microstructure of different steels hardened by a fibre laser. Rolled steel, quenched and tempered steel, annealed alloyed steel and conventionally through hardened steel were tested. Microhardness (HV0·01) was measured in martensite, pearlite, ferrite and cementite structures at different depths below the laser irradiated surface. The microhardness results were compared with the conventional macrohardness (HV5) results. The grain size of rolled ferritic–pearlitic steels had distinct effect on microhardness. The macrohardness of quenched and tempered steel might be markedly influenced by the homogeneity of alloy contents. In high carbon steel, cementite is ∼150 HV harder than pearlite. Annealed alloyed steels achieved high surface hardness but poor hardened depth. Dispersed granular pearlite did not affect the microhardness of soft annealed steel. The macrohardness of the base material was close to the microhardness of the softer phase structure. The measured microhardness was about 100–250 HV higher than the macrohardness.
    Original languageEnglish
    Pages (from-to)34-40
    Number of pages7
    JournalSurface Engineering
    Volume29
    Issue number1
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Steel
    carbon steels
    hardening
    Microhardness
    microhardness
    Carbon steel
    Hardening
    steels
    Lasers
    lasers
    pearlite
    Pearlite
    cementite
    Phase structure
    Fiber lasers
    martensite
    Martensite
    homogeneity
    fiber lasers
    Ferrite

    Keywords

    • steel
    • fibre laser
    • hardening
    • microhardness
    • grain size
    • microstructure

    Cite this

    Qiu, F. ; Uusitalo, J. ; Kujanpää, Veli. / Laser transformation hardening of carbon steel : Microhardness analysis on microstructural phases. In: Surface Engineering. 2013 ; Vol. 29, No. 1. pp. 34-40.
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    title = "Laser transformation hardening of carbon steel: Microhardness analysis on microstructural phases",
    abstract = "This study investigates the microhardness and microstructure of different steels hardened by a fibre laser. Rolled steel, quenched and tempered steel, annealed alloyed steel and conventionally through hardened steel were tested. Microhardness (HV0·01) was measured in martensite, pearlite, ferrite and cementite structures at different depths below the laser irradiated surface. The microhardness results were compared with the conventional macrohardness (HV5) results. The grain size of rolled ferritic–pearlitic steels had distinct effect on microhardness. The macrohardness of quenched and tempered steel might be markedly influenced by the homogeneity of alloy contents. In high carbon steel, cementite is ∼150 HV harder than pearlite. Annealed alloyed steels achieved high surface hardness but poor hardened depth. Dispersed granular pearlite did not affect the microhardness of soft annealed steel. The macrohardness of the base material was close to the microhardness of the softer phase structure. The measured microhardness was about 100–250 HV higher than the macrohardness.",
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    author = "F. Qiu and J. Uusitalo and Veli Kujanp{\"a}{\"a}",
    year = "2013",
    doi = "10.1179/1743294412Y.0000000049",
    language = "English",
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    Laser transformation hardening of carbon steel : Microhardness analysis on microstructural phases. / Qiu, F. (Corresponding Author); Uusitalo, J.; Kujanpää, Veli.

    In: Surface Engineering, Vol. 29, No. 1, 2013, p. 34-40.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Laser transformation hardening of carbon steel

    T2 - Microhardness analysis on microstructural phases

    AU - Qiu, F.

    AU - Uusitalo, J.

    AU - Kujanpää, Veli

    PY - 2013

    Y1 - 2013

    N2 - This study investigates the microhardness and microstructure of different steels hardened by a fibre laser. Rolled steel, quenched and tempered steel, annealed alloyed steel and conventionally through hardened steel were tested. Microhardness (HV0·01) was measured in martensite, pearlite, ferrite and cementite structures at different depths below the laser irradiated surface. The microhardness results were compared with the conventional macrohardness (HV5) results. The grain size of rolled ferritic–pearlitic steels had distinct effect on microhardness. The macrohardness of quenched and tempered steel might be markedly influenced by the homogeneity of alloy contents. In high carbon steel, cementite is ∼150 HV harder than pearlite. Annealed alloyed steels achieved high surface hardness but poor hardened depth. Dispersed granular pearlite did not affect the microhardness of soft annealed steel. The macrohardness of the base material was close to the microhardness of the softer phase structure. The measured microhardness was about 100–250 HV higher than the macrohardness.

    AB - This study investigates the microhardness and microstructure of different steels hardened by a fibre laser. Rolled steel, quenched and tempered steel, annealed alloyed steel and conventionally through hardened steel were tested. Microhardness (HV0·01) was measured in martensite, pearlite, ferrite and cementite structures at different depths below the laser irradiated surface. The microhardness results were compared with the conventional macrohardness (HV5) results. The grain size of rolled ferritic–pearlitic steels had distinct effect on microhardness. The macrohardness of quenched and tempered steel might be markedly influenced by the homogeneity of alloy contents. In high carbon steel, cementite is ∼150 HV harder than pearlite. Annealed alloyed steels achieved high surface hardness but poor hardened depth. Dispersed granular pearlite did not affect the microhardness of soft annealed steel. The macrohardness of the base material was close to the microhardness of the softer phase structure. The measured microhardness was about 100–250 HV higher than the macrohardness.

    KW - steel

    KW - fibre laser

    KW - hardening

    KW - microhardness

    KW - grain size

    KW - microstructure

    U2 - 10.1179/1743294412Y.0000000049

    DO - 10.1179/1743294412Y.0000000049

    M3 - Article

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    SP - 34

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    JO - Surface Engineering

    JF - Surface Engineering

    SN - 0267-0844

    IS - 1

    ER -