Full
Outline
In response to the problem of insufficient fatigue strength of the shear edge of the 700 MPa level frame longitudinal beam, optical microscopy, scanning electron microscopy and fatigue testing machine are used to evaluate the properties of the shear edge under existing process conditions in this paper. The research results indicate that the burrs on the shear edge of the 700 MPa level frame longitudinal beam are effectively removed by rolling deburring process. However, due to the folding caused by burr lodging, the fatigue strength of the shear edge is only 206 MPa, and the fatigue failure originates from the folding root at the rolling edge of the tear band side. To improve the fatigue strength of the shear edge in further, the parameters of the shear edge rolling process are analyzed and optimized combined with CAE analysis. The results show that in order to form a large residual compressive stress on the shear edge, the optimal angle between the roller working surface and the hot-rolled plate surface is 30°~45°, with a rolling depth of 0.5~1.0 mm. The chamfered surface formed by rolling the upper and lower edges of the shear edge is smooth and flat by using optimized rolling process. The hot-rolled surface of the original plate has no obvious protrusions, and there is no outward protrusion in the middle of the cross-sectional profile of the shear edge. Finally, the fatigue strength of the shear edge reaches 263~270 MPa.
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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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