Arcelormittal

Blandine Remy

Emmanuel Lucas

Jean-Christophe Hell

Thierry Sturel

Thierry Iung

Nicolas Charbonnier

Gianni Boi

Colin Scott

A method for manufacturing a recovered steel sheet having an austenitic matrix presenting at least one mechanical property (M) equal or above a target value Mis provided. The method includes a calibrating process involving heat treatments on at least 2 samples of the steel, corresponding to Pareq values P, submitting said samples to X-ray diffraction so as to obtain spectrums including a main peak whose width at mid height FWHM is being measured, measuring a mechanical property (M) of said samples, measuring a recovery or recrystallization state of each sample, drawing a curve of M as a function of FWMH in a domain where the samples are recovered from 0 to 100%, but not recrystallized. The method further includes calculating a FWHMcorresponding to a target mechanical property M, determining a pareq value Pof the heat treatment to perform to reach Mand selecting a time tand a temperature T°corresponding to the Pvalue. The method further includes feeding a recrystallized steel sheet having a M, cold-rolling the recrystallized steel sheet in order to obtain a steel sheet having a Mand annealing the cold rolled steel sheet at a temperature T°during a time t.

Method for producing a TWIP steel sheet having an austenitic microstructure

A press hardened coated steel part with high resistance to delayed fracture, the coating containing (Fe&#x2014;Al) intermetallic compounds resulting from the diffusion of iron into an aluminum or an aluminum-based alloy, or an aluminum alloy of a precoating, wherein the chemical composition of the steel includes, in weight: 0.16%&#x2264;C&#x2264;0.42%, 0.1%&#x2264;Mn&#x2264;3%, 0.07%&#x2264;Si&#x2264;1.60%, 0.002%&#x2264;Al&#x2264;0.070%, 0.02%&#x2264;Cr&#x2264;1.0%, 0.0005&#x2264;B&#x2264;0.005%, 0.002%&#x2264;Mg&#x2264;0.007%, 0.002%&#x2264;Ti&#x2264;0.11%, 0.0008%&#x2264;O&#x2264;0.005%, wherein (Ti)&#xd7;(O)&#xd7;10&#x2264;2, 0.001%&#x2264;N&#x2264;0.007%, 0.001%&#x2264;S&#x2264;0.005%, 0.001%&#x2264;P&#x2264;0.025% and optionally one or more elements selected from the list of: 0.005%&#x2264;Ni&#x2264;0.23%, 0.005%&#x2264;Nb&#x2264;0.060%, the remainder being Fe and unavoidable impurities, and wherein the microstructure includes at least 95% martensite.

Press hardened part with high resistance to delayed fracture and a manufacturing process thereof

Growing community of inventors

Sanry les Vigy, France

Blandine Remy