In this paper, it is introduced the CCT curve of 700 MPa grade high strength steel is measured with the Formastor-F full automatic phase change instrument and its microstructures at various cooling rates of 0.5~118 ℃/s are analyzed. The results showed that the transformation product was ferrite and pearlite when the cooling rate of test steel was 0.5 ℃/s; bainite structure began to form when the cooling rate was more than 1 ℃/s; bainite structure began to increase and perlite structure began to reduce with the cooling rate gradually increased; pearlite structure disappeared as well as the structure was ferrite and bainite when the cooling rate was 10 ℃/s; transformation products were mainly bainite when the cooling rate increased to 118 ℃/s. The analysis on the CCT curve and microstructure of 700 MPa grade high strength steel provide the theoretical basis for formulating heat treatment technology in actual production processes.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |