BIULETYN INSTYTUTU SPAWALNICTWA No. 5/2018 153 dr inż. Krzysztof Pańcikiewicz (PhD (DSc) Eng.); dr inż. Lechosław Tuz (PhD (DSc) Eng.); dr inż. Zbigniew Żurek (PhD (DSc) Eng.) – AGH University of Science and Technology, Kraków Krzysztof Pańcikiewicz, Lechosław Tuz, Zbigniew Żurek A New Look at the Classifcation of Cracks in Welded and Braze Welded Joints Abstract: Te making of structures using advanced materials and joining tech- nologies is frequently accompanied by limited weldability problems. Te obtain- ability of joints characterised by required properties can be limited, among other things, by susceptibility to crack formation. Te article presents an overview of classifcation of cracks in welded and braze welded joints based on reasons for crack formation and the period of crack development. Te primary division of fabrication/production-related cracks includes hot, cold, lamellar and annealing cracks. Te study recommends the extension of the above-presented classifca- tion by including cracks occurring at a temperature higher than ambient tem- perature and lower than the lower limit of high-temperature brittleness range. Te above-named temperature range could include cracks triggered by the loss of plasticity in the solid state resulting from the occurrence of ductility-dip brit- tleness and cracks related to liquid metal embrittlement. Keywords: fabrication-related cracks, production-related cracks, ductility-dip brittleness, liquid metal embrittlement doi: 10.17729/ebis.2018.5/17 Introduction Weldability is one of the key features of metal- lic materials enabling the obtainment of stable joints characterised by appropriate functional characteristics. In turn, one of the major issues related to the metallurgical aspect of weldabil- ity is susceptibility to the formation of various cracks. Te crack can be defned in several var- ious ways. Te PN-EN ISO 6520-1 standard describes the crack as a welding imperfection following the local rupture in the solid state, triggered by cooling or stresses. Te issue of the cracking of welded joints has been known for a long time. In one of the frst issues of the Polish journal Welding and Cutting of Metal- lic Materials (no. 7, published in 1928), the arti- cle entitled On Acetylene Welding and Welding Imperfections indicated that primary welding imperfections included, among other things, a “surface crack” [1]. In reference publications of the time it was also possible to come across other terms. Te 1950s saw the usage of the term of “scratch” de- scribing a crack which did not develop right through and did not form a wide gap [2]. Cracks were divided into internal and surfacing cracks as well as longitudinal and transverse in relation