The Effect of Overloading of Pipes on their Fracture Toughness in Relation to the Strength Grade of Steel

The present experimental results showed a very positive effect of a controlled overloading of a pipeline on its fracture toughness. These results have been referred to steels of the class L360MB and L415MB. However, more recent results obtained on L450MB steel indicated that the positive effect of oveloading is reduced as the strength properties of steels are increased. It follows from this that the final technological operation of overloading of pipes made from steels of an increased strength could be let out from the pipe manufacture scheme. The paper presents experimental results which prove by evidence a decreasing positive effect of overloading on the fracture toughness of steels of high strength properties