To address the issues that existing pipeline gouge failure assessment methods neglect the changes in surface material properties and have insufficient understanding of the cracking risk caused by gouges in high‑strength steel pipes,a gouge simulation and characterization method based on a biaxial loading platform is proposed.A dedicated gouge processing platform was designed and built to prepare gouge specimens under different process parameters(tool shape,vertical pressure,scratching speed),and their cross‑sectional microstructure and mechanical properties were systematically analyzed.The results show that gouges induce significant plastic deformation in the near‑surface layer,forming a distinctly layered metamorphic layer;the grains in the region near the root are severely deformed,resulting in a denser microstructure.Vickers hardness tests reveal that the hardness at the root reaches up to 388HV,nearly twice that of the base material(200HV),and it increases with higher vertical pressure and scratching speed.Based on the hardness distribution,the thickness of the metamorphic layer was determined to exceed 2 mm.Additionally,residual compressive stress exists at the gouge root,with the longitudinal residual stress increasing with depth,while the transverse residual stress decreases with depth.This study provides direct evidence distinguishing gouges from ordinary metal loss defects and offers an important basis for crack initiation analysis and safety assessment of gouges in high‑strength pipeline steel.
| 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 |