The 34CrMo4(AISI 4130)steel is extensively utilized in the compressed natural gas cylinders.Due to the importance of thermomechanical processing in the production of these cylinders,the dynamic recrystallization(DRX)characteristics of 34CrMo4 steel were investigated.The effect of hot deformation parameters such as temperature and strain rate on the dynamic restoration processes of a 34CrMo4 alloy was studied.Hot compression tests were performed in the temperature range of 900 to 1100 ℃ and the strain rate range of 0.001 to 0.1 s-1.Hot workability of this alloy has been analyzed by employing flow localization parameter.The flow curves observed are typical of occurrence of dynamic recrystallization and have exhibited single or multiple peaks in flow stress curve before reaching steady state,depending on the temperature and strain rates.The flow stress decreases with the increase of deformation temperature and the decrease of strain rate.Finally the activation energy obtained in this research is 490.749 kJ/mol. The 34CrMo4 (AISI 4130) steel is extensively utilized in the compressed natural gas cylinders. Due to the importance of thermomechanical processing in the production of these cylinders, the dynamic recrystallization (DRX) characteristics of 34CrMo4 steel were investigated. The effect of hot deformation parameters such as temperature and strain rate on the dynamic restoration processes of a 34CrMo4 alloy was studied. Hot compression tests were performed in the temperature range of 900 to 1100 ° C and the strain rate range of 0.001 to 0.1 s -1. Hot workability of this alloy has been analyzed by employing flow localization parameter. flow rate observed are typical of occurrence of dynamic recrystallization and have reported single or multiple peaks in flow stress curve before reaching steady state, depending on the temperature and strain rates. the flow stress decreases with the increase of deformation temperature and the decrease of strain rate. Finaally the activation energy obtained in this re search is 490.749 kJ / mol.