The effect of different normalizing and tempering temperatures on the microstructure and mechanical properties of plastic mold steel 3Cr2NiMo was studied. The results showed that after normalizing at 810 ℃ and 840 ℃, the martensite lath was short and fine needle shaped with uniform structure, and the original austenite grain size was Grade 11. After normalizing at 900 ℃, the microstructure became coarse, and the original austenite grain size was Grade 9. The normalizing hardness increased first and then decreased with the increase of temperature. It was determined that the appropriate normalizing temperature of the test steel was 840 ℃. When the tempering temperature ranged from 450 ℃ to 500 ℃, the microstructure was tempered troostite, and the lath structure maintained the original martensite orientation. When the tempering temperature was increased to 650 ℃, the microstructure was tempered sorbate without obvious orientation. Subsequently, the carbides became spherical, aggregate and grow, while remaining uniformly dispersed. Moreover, the lath boundaries appeared blurred. The hardness of the test steel decreased with the increase of tempering temperature.
| 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 |