Method for setting shape and working stress, and working environment of steel member
AssigneesKawasaki Steel Corporation, National Institute For Material Science
InventorsShusaku Takagi, Kaneaki Tsuzaki, Tadanobu Inoue
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Abstract
A delayed fracture is effectively prevented by appropriately setting a shape and working stress, and working environment of a high strength member having more than 1,000 MPa of tensile strength. For this end, the relationship between a maximum value of diffusible hydrogen contents of unfailed specimens (Hc) and Weibull stress are found and the content of diffusible hydrogen entered into steel from the environment due to corrosion during the use of the steel member (He) is also found. Then, Weibull stress in the Hc that is equal to the He is found, thus determining the shape and working stress of the steel member so as to provide stress below the Weibull stress.
Claims5
A method for setting a shape and working stress of a steel member comprising the steps of:
- determining the relationship between a maximum content Hc among diffusible hydrogen contents of unfailed steel specimens and Weibull stress;
- measuring an environment content He of diffusible hydrogen penetrating the steel member from the environment;
- determining the Weibull stress σwA when Hc=He;
- and
- determining the shape and working stress of the steel member when the Weibull stress σwB in actual use is below the Weibull stress σwA.
A method for setting a working environment of a steel member comprising the steps of:
- determining the relationship between a maximum content Hc among diffusible hydrogen contents of unfailed steel specimens and Weibull stress σwA;
- determining Weibull stress σwB of the steel member in actual use based on a shape and working stress of the steel member in actual use;
- determining Hc when σwA=σwB;
- and
- determining a working environment of the steel member when a content of diffusible hydrogen penetrating the steel member from the environment He is below the Hc.
A method for setting a shape and working stress of a steel member comprising the steps of:
- determining the relationship between a maximum content Hc among diffusible hydrogen contents of unfailed steel specimens and Weibull stress σwA;
- measuring an environment content He of diffusible hydrogen penetrating the steel member from the environment;
- determining the Weibull stress σwA when Hc=He;
- and
- comparing the σwA to the Weibull stress σwB which is calculated from a shape and working stress of the steel member in use, and determining that there will be no delayed fracture when the σwA is larger than the σwB.
Dependencies are inferred from the claim text.