Mechanical properties of 0Cr18Ni12Mo2Ti Steel at Low Temperature
The 0Cr18Ni12Mo2Ti steel is a kind of austenitic stainless steel, which has a high temperature strength and corrosion resistance. Its low temperature mechanical properties are of great importance for some engineering applications, such as pumps and valves. Therefore, it is necessary to investigate the mechanical properties at low temperature.
The mechanical properties of 0Cr18Ni12Mo2Ti steel at cryogenic temperature were studied by means of tensile tests. The testing temperature ranged from -196 °C to 100 °C. During the tests, the temperature was kept constant throughout the duration of the test. The tensile specimens were prepared in accordance with ASTM A264-87 standard and tested in a 10000 kN tensile tester. The test results showed that the strength of 0Cr18Ni12Mo2Ti steel decreases with decreasing temperature at cryogenic temperature. At -196 °C, the ultimate tensile strength is 608 MPa and the yield strength is 437 MPa. The elongation decreases from 58.3 % at room temperature to 43 % at-196 °C. The reduction in area also decreases from 43.2 % at room temperature to 34.2 % at -196 °C. Moreover, the impact energy decreases from 65 J at room temperature to less than 10 J at-196 °C.
The mechanical properties of 0Cr18Ni12Mo2Ti steel at low temperature have been studied by means of impact tests. The impact specimens were prepared in accordance with ASTM A328 standard and tested at room temperature. The Charpy V-notch specimens are tested in an LT-40 impact tester according to ISO 148-1:2013. The impact energy is measured at four different temperature, 25 °C, 0 °C, -20 °C and -196 °C. The impact energy decreases with decreasing temperature. At -196 °C,the impact energy decreases to lower than 10 J.
In order to evaluate the low-cycle fatigue life of 0Cr18Ni12Mo2Ti steel, the low-cycle fatigue test was carried out in a Lofecox F-300 servo hydraulic fatigue testing machine which can work up to -196 °C. The test result showed that the fatigue strength decreases with decreasing temperature below 0 °C and then decreases rapidly at -196 °C. According to the fatigue data, the fatigue life decreases from 8×106 cycles at room temperature to 30×103 cycles at -196 °C.
The effect of temperature on the mechanical properties of 0Cr18Ni12Mo2Ti steel was studied by means of hardness test. The Vickers hardness test was carried out using a XPL-103 Rockwell-Vickers hardness tester. The test results showed that the hardness decreases with decreasing temperature down to -80 °C and then decreases rapidly at -196 °C. At-196 °C, the hardness is lower than 50HV.
In conclusion, the mechanical properties of 0Cr18Ni12Mo2Ti steel decrease with decreasing temperature at cryogenic temperature. The ultimate tensile strength, yield strength and impact energy decrease from 608 MPa, 437 MPa and 65 J at room temperature to lower than 500 MPa, 304 MPa and 10 J at -196 °C, respectively. The reduction in area and the elongation decrease from 43.2 % and 58.3 % at room temperature to 34.2 % and 43.0 % at -196 °C, respectively. The low-cycle fatigue life decreases from 8×106 cycles at room temperature to 30×103 cycles at -196 °C. The hardness also decreases with decreasing temperature and is lower than 50HV at -196 °C.
