Abstract This design is mainly research and analysis the fatigue life of the material terms and expressions calculation method and calculation of the 45 # first phase of fatigue life. Then the preparation of these fatigue and fatigue life of expression procedures. The final procedure used for good Data to calculate the number of verified, validated and those of experimental data to see whether similar to that study by the expression is correct. The proposed new equation for calculating the life of projects in the area on the mechanics of materials, damage mechanics, micro-fracture mechanics, the macro-fracture mechanics of the relationship between the layman's language and understanding, acceptance and application of a practical significance.
Key Words: Fatigue strength ; Life expectancy estimates; Procedures; 45# Steel.
