The chemical composition of wire rod for 2 200 MPa ultra-high strength steel strand is designed based on the chemical composition of SWRH82B. The Φ14 mm wire rod is rolled by second heating and cogging with 280 mm×380 mm continuous casting billet. The tensile strength of hot rolled wire rod is increased from 1 150 MPa to over 1 450 MPa by optimizing the cooling rate of wire rod. The target that the strength of steel strand reaches over 2 200 MPa after drawing is realized. The results of industrial trial production showed that the time of soft blow and deep vacuum was the key to control the size of non-metallic inclusions and oxygen content in steel as well as it should be more than 15 min; under the condition of constant casting speed and the degree of superheat is below 35 ℃, the center macrosegregation index could be controlled below 1.15; the ideal microstructure of sorbite could be obtained by controlling moderate cooling rate and optimum cooling rate was 4.89~5.62 ℃/s.
| 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 |