Clean Cast Steel Technology: Effect of Micro-porosity on Tensile and Charpy Properties of Four Cast Steels

Griffin, John, A. ; Bates, Charles, E.

University of Alabama at Birmingham, Birmingham, AL

关键词: Steel;    Tensile;    32 Energy Conservation, Consumption, And Utilization Steel;    Casting;   

DOI  :  10.2172/850235
RP-ID  :  DOE/ID/14229-Final
RP-ID  :  FC36-02ID14229
RP-ID  :  850235

美国|英语

来源: UNT Digital Library

【 摘 要 】

The effect of these large shrink cavities on mechanical properties could be easily calculated using well established engineering formulas. Over the years, increases in computational and metallurgical resources have allowed the modeler to improve accuracy and increase the complexity of numerical predictors. An accurate prediction of micro-porosity, not observable using conventional radiographic techniques, and an engineering understanding of the effect on mechanical properties would give a designer confidence in using a more efficient casting design and a lower safety factor. This will give castings an additional design advantage. The goal of this project is to provide current and future modelers/designers with a tensile and Charpy property dataset for validation of micro-porosity predictors. The response of ultimate strength, elongation, and reduction in area to micro-porosity was very similar in all four alloys. Ultimate strength was largely unaffected by tensile fracture surface porosity until values of about 25% were reached and decreased linearly with increasing values. Elongation and reduction in area decreased sharply after less than 5% fracture surface porosity. Niyama values of about 0.7 were produced sound material and acceptable tensile properties. Ultrasonic velocities of 0.233 in/usec and higher produced acceptable tensile properties. Metallographic examination revealed a ratio of 4-6 to 1 in fracture surface porosity to metallographic porosity. Charpy impact properties were largely unaffected by the microporosity concentrations examined in this study and did not correlate to either Niyama values, fracture surface porosity, or metallographic porosity.