To address the forged jourral fracfure of a mcdium-and-heary-duty vehicle, by analyzing the macro and micro morphology of the fracture of the forged journal, it is determined that the source of the crack is located in the center of the neck journal, and the crack spreads from inside to outside. It is judged that the crack is the thermal stress type cracking appearing in the quenching process, and the component segregation of raw materials also plays a certain role in promoting the cracking of the neck journal. The risk of quenching thermal stress cracking caused by excessive neck journal section size is reduced by the process adjustment of the neck position of the forged journal shaft: interior hole first and then tempering treatment, and the influence of the segregation of the core components of the neck journal on cracking is eliminated at the same time. By optimizing and adjusting the production process of forged journal, the risk of quenching crack is reduced and the reliability of the product is improved.
| 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 |