engleski

Mechanical Properties Determination and Crack Behavior Prediction for Steels 1.4057 and 1.7225

Optimal selection of material is one of the crucial points of construction design process. Bearing that in mind, this paper gives comparison of two types of steel, stainless steel 1.4057 and low alloy steel 1.7225. Experimentally obtained data related to the mechanical properties are presented, specifically stress-strain diagrams, ultimate tensile strength and yield strength. Measured values showed higher values of yield strength and ultimate tensile strength for 1.4057 when comparing them to 1.7225. In addition, crack driving force is numerically assessed. J-integral, an important fracture mechanics parameter, is chosen as a fracture criterion of considered materials. J-integral values are determined numerically using finite element (FE) stress analysis results of single-edge notched bend (SENB) and compact tensile (CT) type specimens usually used in standardized J-integral experimental procedures. Obtained J values are plotted versus specimen crack growth values (Δa) for different specimen geometries (a/W). Higher resulting values of J-integral for 1.4057 than 1.7225 can be noticed. Also, higher a/W ratios correspond to lower J-integral values of materials and vice versa. In addition to that, J-integral values obtained by using FE model of CT specimen give somewhat conservative results when compared with ones obtained by FE model of SENB specimen. Although this procedure differs from experimental analysis, results can be used a suitable fracture parameter value in fracture toughness assessment.

Steel 1.4057; steel 1.7225; fracture

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