THE HARDNESS ANALYSIS OF THE HARDNESS ANALYSIS OF THE IF SHEET STEEL AFTERTHE IF SHEET STEEL AFTER A PLASTIC DEFORMATION A PLASTIC DEFORMATION

Mihaliková Mária – Ambriško Ľubomír – Pešek LadislavMihaliková Mária – Ambriško Ľubomír – Pešek Ladislav

Department of Materials Science, Department of Materials Science, Faculty of Metallurgy, Technical Faculty of Metallurgy, Technical

University of Košice, Slovak RepublicUniversity of Košice, Slovak Republic

Telč 2009

IntroductionIntroduction

Behaviour Behaviour of of IF steel has been observed in IF steel has been observed in this contribution. Steels were loaded by static this contribution. Steels were loaded by static tension by the loading rate 1.3 mm/min. tension by the loading rate 1.3 mm/min.

Videoextensometry method has been used Videoextensometry method has been used for scanning of the distribution of deformation for scanning of the distribution of deformation nearly before fracture. nearly before fracture.

Experimental materialExperimental materialFor tensile tests were applied specimens from IF cold rolled steel sheets.

IF (interstitial free) steel, with thickness 1.8 mm.

Microstructure

Steel Mechanical properties

Rp 0.2

[MPa]

Rm

[MPa]

A5

[%]

IF 185 300 45

Experimental methodsExperimental methods

CCDcamera

ComputerSpecimen

Light

1 2 3 4 5 6 7 8 9

Principe of UCIPrincipe of UCI

V-Vickers diamondR-Resonant rodF-FixingT-Transmitting

Relation between HV1 and Relation between HV1 and y y of steel IFof steel IF

0

100

200

300

400

500

600

0 20 40 60 80 100 120 140 160 180

y [%]

HV

1

column 2

column 6

1 2 3 4 5 6 7 8 9

ConclusionsConclusions

Using the videoextensometry and hardness HV1 test enables

to characterize the relation between the plastics deformation y

and hardness.

The power relation between the hardness HV1 and longitudal

deformation was applied.

UCI is practical, portable method appropriate to satisfactory

determination of deformation state of materials.

Thank you for your Thank you for your attentionattention

This study was supported by the Grant Agency of Slovak Republic; grant project VEGA No. 1/4149/07 and APVV No. 0326-07.