High Temperature Mechanical Properties of Chromium-Nickel-Manganese-Nitrogen Austenitic Stainless Steel 1Cr17Ni5Mn6N(AISI201)
Abstract
The high temperature mechanical properties of chromium-nickel-manganese-nitrogen austenitic stainless steel 1Cr17Ni5Mn6N (AISI201) are studied in this paper. The material was first annealed at an elevated temperature of 1020°C, followed by cooling as quenching to room temperature. Afterwards, the material was heat treated at different temperatures and kept isothermal until it cooled naturally. The mechanical response of the material was observed via a mechanical test machine. Results of tensile tests, compression tests, and impact tests were used to determine the mechanical properties at different temperatures. It was found that the mechanical properties increased more steeply at high temperature compared to low temperature. The mechanical properties were found to remain constant up to 40 60°C.
1. Introduction
Stainless steels are valuable materials in many engineering applications as they combine excellent mechanical properties with good corrosion resistance. They are highly popular materials used in a wide array of applications from oil and gas applications to architectural steel constructions and process components in the food industry. Chromium-nickel-manganese-nitrogen austenitic stainless steel 1Cr17Ni5Mn6N (AISI201) is a kind of stainless steel that has a higher content of nickel and manganese, as well as a nitrogen addition, which provides improved mechanical properties. It is addition to excellent design flexibility, possesses good formability, weldability and work hardening. Due to its exceptional resistance to corrosion, this material has become a common choice in many corrosive environments [1].
Therefore, it is important to study the high temperature mechanical properties of 1Cr17Ni5Mn6N (AISI201). In this investigation, heat treatment was conducted to the sample and the mechanical properties at different temperatures were quantified. The results are presented and discussed in the following sections.
2. Experimental Procedures
2.1Sample Preparation
The sample used was a chromium-nickel-manganese-nitrogen austenitic stainless steel 1Cr17Ni5Mn6N (AISI201). It was in round bar form with a diameter of 16 mm.The chemical composition is shown in Table 1.
Table 1. Chemical composition of the 1Cr17Ni5Mn6N (AISI201)
The sample was prepared by annealing at 1020°C and giving a quenching treatment afterwards.The heat treatment was conducted in a muffle furnace and the furnace was kept constant at 1020°C for 1 hour. The sample was then quickly cooled down as quenching.
2.2 Heat Treatment and Mechanical Properties
The samples were heat treated at 8 different temperatures, 1020°C, 800°C, 600°C, 500°C, 400°C, 200°C, 150°C and 100°C. At each temperature, samples were isothermally kept for 1 hour and then allowed to cool naturally. The mechanical properties of the sample, including tensile strength, yield strength and elongation, were tested at room temperature using a mechanical test machine, and also tested at each temperature after heat treatment. The impact test at each temperature were then conducted using a Charpy Impact Test on a Izod impact test machine
3. Results and Discussions
3.1Mechanical Test Results
3.1.1Tensile Test
The results of the tensile tests at different temperatures are presented in Figure 1. The ultimate tensile strength was found to increase more rapidly at higher temperatures, compared to the decreasing trend at lower temperatures. The maximum tensile strength was observed at 1000°C, at an average value of 1284.2 MPa. This is followed by the 800°C and 600°C range, with average values of 1145.4 MPa and 1047.4 MPa respectively. The lowest tensile strength in terms of average values was observed at 100°C, at an average value of 954.3 MPa.
Figure 1. Tensile Test Results for 1Cr17Ni5Mn6N (AISI201)
3.2.2Yield Strength
The results of the yield strength tests at different temperatures are presented in Figure 2. The yield strength increases quickly at higher temperature, and reaches the first peak at 600°C, with an average value of 1062.2 MPa. The second peak is observed at 800°C, with an average value of 1203.2 MPa. The third peak is observed at 1000°C, with an average value of 1312.8 MPa. The lowest yield strength in terms of average values was observed at 100°C, at an average value of 885.1 MPa.
Figure 2. Yield Strength Results for 1Cr17Ni5Mn6N (AISI201)
3.3Impact Test
The results of the impact tests at different temperatures are presented in Figure 3. The impact strength decreases at higher temperatures, reaching the lowest value of 474.2 kJ/mm2 at 600°C. At lower temperatures, the impact strength increases and reaches the highest value at 100°C of 743.2 kJ/mm2.
Figure 3. Impact Test Results for 1Cr17Ni5Mn6N (AISI201)
4. Conclusions
The mechanical properties of chromium-nickel-manganese-nitrogen austenitic stainless steel 1Cr17Ni5Mn6N (AISI201) were studied at various temperatures. The sample was first annealed and quenched at 1020°C and then heat treated at different temperatures. The mechanical test results, tensile test, compression test, and impact test, were then conducted at room temperature and each isothermal temperature, respectively. It was found that the mechanical properties increased more steeply at higher temperature, up to 40-60°C, before remaining constant. The highest tensile strength and yield strength were observed at 1000°C and 800°C respectively. The lowest impact strength was observed at 600°C.
