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

8 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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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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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

VL - 29

SP - 34

EP - 40

JO - Surface Engineering

JF - Surface Engineering

SN - 0267-0844

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ER -