| 摘要 |
<p>The invention concerns steel for making a cleavable mechanical part characterised in that its chemical composition comprises (expressed in weight proportions): 0.2 % </= C </= 0,4 %; 0,1 % </= Si 1.5 %; 0.3 % </= Mn </= 1.4 %; 0 % </= Ni +Cr </= 0.45 %; 0 % </= Mo </= 0.06 %; 0 % </= Cu </= 0.5 %; 0.2 % </= V </= 0.5 %; P </= 0.150 %; 0.005 % </= N </= 0.02 %; optionally one or several elements selected among lead up to 0.1 %, tellurium up to 0.15 %, bismuth up to 0.15 %. selenium up to 0.02 %, sulphur up to 0.35 % and calcium up to 0.005 %; optionally at least one element selected among titanium up to 0.05 %, niobium up to 0.1 % and aluminium up to 0.07 %, the remainder being iron and impurities and residuals resulting from the preparation; the steel having an essentially ferrito-pearlitic structure, the ferritic fraction being less than 20 %, the tensile strength of the steel being less than 1000 MPa, the yield strength being more than 700 MPa, the ratio Re/Rm being more than 0.73 and the Kcv impact strength being less than 7 Joules/cm<2>. The invention also concerns a method for making a cleavable part and the resulting part.</p> |
