The effect of austenization temperatures and holding times on the mechanical properties of armor steels

The effect of the austenization temperatures and holding times on the mechanical properties of armor steels was investigated. The samples used in this research are armor steel A and B. The test samples were subjected to austenization at the temperatures of 825, 850, 875, 900, and 925°C in the holding times of 10, 20, 30 and 40 minutes and followed by water quench. The as-quenched samples were then tempered at 200°C for 20 minutes. The samples were then tested by the Vickers Hardness test, Charpy V-Notch Impact Test, and tensile test. The quenched and tempered steels showed a fully tempered-martensite microstructure. The highest hardness was achieved at austenization at 825°C for 20 minutes for steel A and a temperature of 850°C for 20 minutes for steel B, with a hardness of 541.5 HB and 539.7 HB, respectively. The highest toughness of both samples was obtained at austenization at 900°C for 20 minutes i.e., 27,364 J. The highest UTS at austenization temperature was 825°C for 20 minutes for steel A and temperature at 900°C for 20 minutes for steel B, with UTS respectively 1781.03 MPa and 1937.41 MPa. The fractography observation by using SEM on the impact test samples showed the ductile-type fractures.