محمد مويدي تكمه داش

Low-carbon manganese steels are widely used in the casting industry, particularly in railway applications, due to their low cost and unique properties such as sufficient yield strength, low ductile-to-brittle transition temperature, and good formability. In this study, the effect of casting modulus on the microstructure and mechanical properties of G24Mn6 steel was investigated. For this purpose, microstructural analysis was performed on two samples with casting moduli of 10 mm and 50 mm. Rockwell and Vickers hardness tests, impact tests at temperatures of -30°C and +25°C, and tensile tests were conducted. The results showed that with increasing casting modulus, the grain size increased. Image analysis using ImageJ software indicated that the ferrite grain size increased from 2.52 µm in the 10 mm casting modulus sample to 14.33 µm in the 50 mm casting modulus sample. Additionally, the amount of bainite increased as the casting modulus decreased, rising from 16% in the 50 mm casting modulus sample to 66% in the 10 mm casting modulus sample. Hardness and tensile test results revealed that the hardness of the 50 mm casting modulus sample increased from 164 Vickers to 254 Vickers in the 10 mm casting modulus sample. Similarly, the yield strength and ultimate tensile strength increased from 340 MPa and 574 MPa to 556 MPa and 685 MPa, respectively. The impact energy absorption of the 50 mm casting modulus sample was 96.3 J/cm² at room temperature and 10.29 J/cm² at -30°C. In contrast, the 10 mm casting modulus sample exhibited 103.6 J/cm² and 24.55 J/cm² in the same temperature conditions. Fracture surface analysis revealed that the fracture mode in both samples was a mixture of brittle and ductile fracture. Non-destructive gamma and ultrasonic testing, along with an investigation of inclusions in both samples, showed that shrinkage cavities were significantly more preva‎lent in the 50 mm casting modulus sample, with a maximum cavity diameter of up to 2 mm.

مدول ريختگي , فولاد G24Mn6 , ريزساختار , خواص مكانيكي

Casting Modulus , G24Mn6 Steel , Microstructure , Mechanical Properties

mohammad moayyedi

mohammad ali boutorabi