This work presents developmental stages and the most important results of two new experimental test methods to measure the critical strain to prevent the surface crack formation under continuous cast conditions. These experimental methods are the Situ Characterization - Tensile (IMC-T) and the In - Situ Characterization Bending (IMC-B)Method. The first method is based on the tensile test with the in - situ solidified shell on the test body. The second method is the 3 - point bending test with samples, which are produced in a special mold. Both methods allow the measurement of the cracking susceptibility of steels with directly solidified samples from the melt. The samples are characterized by directional solidification, grain growth and precipitation according to the simulated continuous casting process. These methods allow also the controlled cooling of the samples to the testing temperature. Therefore it is the first time possible to investigate the crack formation in consideration of all necessary material and process parameters.