The paper deals with identifying the causes of surface failure of a shaft made of material 42CrMoS4. On the basis of microstructural analysis completed by hardness testing. the occurrence of undesirable phases. such as non-metallic inclusions in the structure of the shaft. https://www.diegojavierfares.com/best-price-TaylorMade-P790-Aged-Copper-Irons-Steel-super-grab/