Steels T23 and T24 developed as materials for welding water cooling membranes without using post-welding heat treatment are studied. The mechanical properties and the microstructure of welds of these steels are determined in the initial condition and after tempering. It is shown that post-welding treatment of welds of steels T23 and T24 is a necessary operation. © 2011 Springer Science+Business Media, Inc.