Abstract: In the course of this report,various data from a considerable amount of experimental work have been discussed.It is found that the solidification brittleness tempe-rature range (BTR) and critical strain value (εmin) have their limitations for the quantitative evaluation of solidification crack susceptibility.On the other hand,as critical strain rate for temperature drop (CST) could reflect the effects of both the metallurgical factors of materials and the welding parameters,it is therefore a suitable criterion for the quantitative evaluation.Comparisons among the crack susceptibility with CST as the criterion of several tyres of low alloy pressure vessel steels,such as 19Mn5,BHW-35,14MnMoV,16Mn,etc.,were made.The relationship between the welding heat input and the susceptibility wss found.The results from the lab are well in line with these in production.