Uticaj unete količine toplote pri zavarivanju na žilavost metala šava mikrolegiranih čelika

Abstract

Žilavost metala šava, jedan od kriterijuma prihvatljivosti zavarenog spoja, zavisi od količine unete toplote. Udarna žilavost metala šava dva toplo valjana mikrolegirana čelika, zavarena elektrolučnim postupkom u zaštiti mešavine gasova (Ar + 5% CO2+0,91% O2) je ispitana merenjem energije loma na instrumentiranom Šarpijevom klatnu. Utvrđeno je da je količina unete toplote od 7 kJ/cm optimalna za žilavost metala šava oba ispitivana čelika. Energija rasta prsline, kao bitna za žilavost metala šava, je za ovu količinu unete toplote veća od kritične, pa se ovako zavareni spoj može preporučiti za konstrukcije koje rade na niskim temperaturama.

Weld metal toughness, one of weldment acceptability criteria, depends on heat input. Weld metal impact toughness of two hot rolled microalloyed steels, welded by electric arc with mixture gases shielding (Ar + 5% CO2+0,91% O2) is tested by measuring impact energy on instrumented Charpy pendulum. It has been found that heat input of 7 kJ/cm is optimal for weld metal toughness of both investigated steels. Crack growth energy, as substantial for weld metal toughness, is for this heat input higher than critical, and welded joint, produced in this way, can be recommended for manufacturing of welded structures for low temperature application.