MECHANICAL PROPERTIES OF HEAT AFFECTED ZONES AT MACRO- AND MICRO- STRUCTURAL LEVEL, USING THERMAL CYCLE SIMULATION MEHANIČKE OSOBINE ZONE UTICAJA TOPLOTE NA MAKRO- I MIKROSTRUKTURNOM NIVOU PRIMENOM SIMULACIJE TOPLOTNOG CIKLUSA

It is almost impossible to produce welded joints with homogeneous structure. This structure is composed from at least three different regions: base material, weld metal and heat affected zone (HAZ). In many welded structures the coarse-grained HAZ is considered to be the preferred location for initiation and propagation of cracks. Since the HAZ is too small, and it is very difficult to obtain data on mechanical properties, in this paper a thermal cycle simulator is used to achieve some test specimens from P355NH steel for pressure vessels. This paper offers information regarding the chemical content of welded joints in percent, estimation of macromicrostructure in specific areas of the welded edge joints and determination of HV10 hardness of specific areas of the welded joints, both for butt welding and thermal cycle simulator specimens. Kljucne reci