Uticaj prsline na karakteristike zavarenog spoja pri različitim vrstama opterećenja

Zijah Burzić,Srđa Perković,Vencislav Grabulov,Meri Burzić

doi:10.5937/str1801050b

Abstract

The application of high strength steels in design of heavy duty welded structures requires data about properties in different loading conditions. Thanks to high yield stress the wall thickness can be reduced compared to mild structural steels, and accordingly welded joint cross-sections, welding consumables consumption and time for welded joints manufacturing will be minimized. This is of importance for pressurized equipment, but also for other industrial branches (cranes, excavator). Complete characterization of welded joint has to include data for parent metal, but also the properties for weld metal and the heat-affected-zone (HAZ) are necessary, at least in order to compare them with parent metal properties. This is of special importance because of heterogeneity structure in HAZ.

Highlights

IN selecting a material for a particular application, the ease and cost of welding must be considered and the material selected should be that which gives a welded vessel of the adequate properties for the minimum cost
It is interesting that the difference in fatigue threshold value, the value of stress intensity factor range, ΔKth, at which existing crack will not grow is not significant: it is 10.22 MPa m1/2 for base metal, 9.11 MPa m1/2 for weld metal and 8.51 MPa m1/2 for heat-affected-zone [5]
The application of high strength steel and its welded joint in structures, exposed to high loads can be accepted if the properties satisfy strong requirements

Summary

Introduction

IN selecting a material for a particular application, the ease and cost of welding must be considered and the material selected should be that which gives a welded vessel of the adequate properties for the minimum cost. It is to notice that their critical values: plane strain fracture toughness KIc, critical COD and JIc, measure of fracture toughness, can be used as material properties of homogeneous material The standards for their determination by testing are well defined, applying quasi-static loading. Complete description of material crack resistance includes data obtained in the following test [4,5,6]: - Determination of convenient fracture mechanics parameter (KI, COD - δ or J integral), and, when possible, its critical value. When welded joints are considered many problems in testing and results evaluation are connected with their microstructural heterogeneity These are the reasons it is not possible, like in case of parent metal, to determine properly the crack resistance parameter for welded joint, since the critical microstructural region is not properly defined.

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Conclusion