The latest state of the art of experimental and theoretical investigation for defining the hot cracking sensitivity of austenitic materials, filler metal and applied welding procedures is reported. On the basis of hot cracking theories both detailed theoretical statements as well as hot cracking criteria for the assessment of various stages of hot cracking are developed. The expressiveness of hot cracking tests (varestraint test, transvarestraint tests, PVR test and hot tensile test) and their special test criteria are different. The thermal, mechanical and temporal influences on the stages of hot cracking initiation are observed and classified by its origin of material, welding procedure and specimen size. The Institute of Joining and Beam Technology has at its disposal the largest PVR testing equipment in Europe, for the time being. Diverse applications of the PVR test are introduced. The sensitivity against solidification cracking in weld metal and liquation cracking and ductility dip cracking in heat-affected base metals or weld metals are quantified for a weldment during a definite welding procedure on one specimen only. The tested materials include austenitic stainless steels in various compositions and alloys on the bases of Ni, Al and Mg. In the standard test procedure of the PVR test for material selection a linear increased tension speed in welding direction is superposed by a bead on plate TIG welding. For the optimisation of welding processing any variation of welding procedures (gas-shielded metal-arc welding, TIG welding, laser welding) can be applied. The limits of the quantifying criteria for hot cracking sensitivity by test procedures are proved by the critical hot cracking initiation during welding of large welding components. An assessment diagram for hot cracking initiation of weldment is developed by a substantial experiment package during fabrication welding of large components.