Vlastnosti materiálu Cr/Ni oceli spojeného s titanem výbuchem

Abstract

Presented paper is focused to chosen properties of Ti + Cr/Ni bimetal and some properties of Ti + MnC one welded by explosion after welding and heat treatment (HT, 600°C/1.5h/air) and after followed HT 600°C/1.5h/air. In case of Ti + Cr/Ni bimetal, metallographic parameters were evaluated, e.g. grain size, wave length, amplitude etc. again after the both HT. Tensile tests and Charpy tests were carried out and also micro-hardness evaluation through welds of both bimetals. In welds of Ti + Cr/Ni bimetal after both HT and also after hydrogen charging, fatigue properties proofed favourable influence of the HT and negative hydrogen impact on threshold level (decrease from 70 MPa to 40 MPa). Fracture was predominantly realised in area of joint. The HT on hydrogen induced cracking (HIC) showed similar effect, even when this static test complied with NACE Standard TM0284-2011. In given case cracks were only propagated in intermetallic area. Phase analysis in this area was carried out by SEM EDX, EBSD and also using synchrotron. The last two mentioned techniques proved presence of Fe2Ti only. The HT of the Ti + MnC bimetal led to the worse results of fatigue properties in three point bent and total strengthening increase including micro-hardness. Bimetal Ti + Cr/Ni is preferentially used in heavy chemistry and in energetic.