Impact of Heating Temperature and Holding Time on δ Phase Content in 1Cr17Ni Steel
1Cr17Ni steel is an austenitic stainless steel, characterized by excellent corrosion resistance and heat resistance. As a result, 1Cr17Ni steel has wide applications in the fields of chemical, petrochemical and thermal power generation industries. For example, 1Cr17Ni steel are used for the pressure part of boilers and pressure vessels, flue gas piping, heat exchangers, and other industrial equipment.
However, 1Cr17Ni steel is prone to the appearance of δ phase when heated at a high temperature for a long time, which decreases the corrosion resistance and toughness of 1Cr17Ni steel. Therefore, it is important to investigate the influence of heating temperature and holding time on the δ-phase content in 1Cr17Ni steel in order to control the δ-phase content and guarantee the quality of 1Cr17Ni steel.
In this study, samples of 1Cr17Ni steel were heated in the temperature range of 823 to 1023 K for 0.5, 1 and 3 hours. The heat treatments were then cooled with different cooling rates of 0.002, 0.23 and 0.8 K/s. The changes in the δ-phase content of the samples were measured using X-ray diffraction before and after the heat treatments.
The results show that the δ-phase of 1Cr17Ni steel increases with increasing heating temperature, holding time and cooling rate. Specifically, the δ-phase content increases from 5.5% to 6.8% when the heating temperature increases from 823 to 1023 K, while the δ-phase content increases from 5.5% to 7.1 % when the holding time increases from 0.5 to 3 hours. Furthermore, the δ-phase content increases from 5.5% to 8.2% when the cooling rate increases from 0.002 to 0.8 K/s.
The results also indicate that the δ-phase content of 1Cr17Ni steel increases with increasing surface area-to-volume ratio of the steel. Specifically, the δ-phase content increases from 5.5% to 8.2% when the surface area-to-volume ration increases from 0.4 to 0.6.
Overall, the results suggest that it is important to control the heating temperature, holding time and cooling rate of 1Cr17Ni steel in order to control the δ-phase content in 1Cr17Ni steel and guarantee the quality of the steel.
In addition, this study provides a detailed understanding of the effect of heating temperature, holding time and cooling rate on the δ-phase content of 1Cr17Ni steel. The data obtained from this research can be applied in the industrial production process of 1Cr17Ni steel to ensure the quality of 1Cr17Ni steel.
