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Outline
The high strength steel Q550D used in engineering machinery was developed by composition optimization and rolling process optimization in Baotou Steel. The welding performance of Q550D high strength steel was analyzed by the maximum hardness in heat affected zone, the implant test and the Y-slit type cracking test, and the results show that: The highest hardness (HV10) for heat affected zone of Q550D steel plate is 297. The result of implant test shows that under the condition of moderate restraint, Q550D steel plate with 20 mm thickness was welded by HS-70 welding stick, there is no crack without preheating. At the same time, the Y-slit type cracking test shows that under the condition of no preheating to weld Q550D steel plate with 20 mm thickness, the surface crack rate and the cross section crack rate of the two groups of samples are zero.
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| 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 |
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