Investigation of the effect heat treatment on mechanical properties of 30mncrb4-2 and 33mncrb5 tempered steels

Wind turbines, which are one of the most widely used renewable energy sources today, continue to be widely installed in our country. The use of fasteners is quite common and important in sectors such as construction, automotive, bridges, highways, rail systems, especially in these turbines. Steels have a critical effect on the production of fasteners used. Today, it is aimed to introduce new types of these steels with less cost and more suitable mechanical properties to the fastener production sector. In this study, the mechanical properties of 30MnCrB4-2 and 33MnCrB5 steels, which are not widely used for fasteners in the market conditions, were determined by tensile test, hardness tests, charpy impact test, chemical analysis test and metallographic structure examination to determine whether the mechanical properties of 30MnCrB4-2 and 33MnCrB5 steels, which are not widely used for fasteners in the market conditions, will comply with the 10.9 quality in the content of ISO 898-1, which is the quality standard for fasteners at different tempering temperatures after the annealing process. When the results are evaluated, the test results of 33MnCrB5 material at 455 ℃ and 475 ℃ tempering temperatures for Ø49 material used in the experiments met the all the requirements of 10.9 quality.30MnCrB4-2 material, on the other hand, met all the requirements of 10.9 quality only at 445 ℃ tempering temperature. This paved the way for the use of a new material as well as steels such as 42CrMo4, 41Cr4, which are most commonly used in the production of fasteners.