三种摇枕、侧架用钢低温性能比较研究

Study on Low Temperature Performance of Three Kinds of Steels for Bolster and Side Frame

通过金相组织观察、力学性能试验和微观断口观察研究了低温对铁路货车摇枕、侧架用钢的影响,选择最优钢种用于高寒地区和国家铁路货车。夏比V口冲击试验表明,各钢种随温度的降低,材料冲击性能下降。温度降至-30℃,低温B级钢冲击功为33 J,冲击断口形貌韧性断裂与脆性断裂各占50%。B+钢冲击功为28 J,断口形貌与低温B级钢类似。20ГФЛ钢冲击功仅为12 J,以脆性断裂为主。降至-60℃时,低温B级钢冲击功为13 J,以脆性断裂为主,但仍具有极少量韧性断裂。B+钢与20ГФЛ钢冲击功仅为12 J、4 J,为脆性断裂。自-10℃至-70℃,从冲击性能数据到微观断口观察均可发现低温B级钢优于B+钢和20ГФЛ钢。低温B级钢的常规力学性能和低温冲击性能均超过摇枕、侧架用钢所要求的力学性能指标,与20ГФЛ钢和B+钢相比,低温B级钢的低温冲击性能更为优良。

The effects of low temperature on the steel used in bolster and side frame of freight train were studied by observing the microstructure, mechanical properties test and microscopic morphology observation. The best kind of steel was used in alpine regions and countries. The test ofCharpy V notch shows that along with the decrease of temperature, the impact propertie is reduction. As the temperature decreasing to -30℃, the impact power of low temperature grade B steel is 13 J, the ductile fracture and brittle fracture each accounts for 50% in impact fracture morphology. The impact power of B＋ steel is 28 J. The fracture morphology is similar with low temperature grade B steel. The impact power of 20Гфл steel is brittle fracture. To -60 ℃, the impact power of low temperature grade B steel is 13 J, the fracture morphology is mainly brittle, but still has a very small amount of ductile fracture. The impact power of B ＋ steel and 20ГФЛ steel is 12 J, 4 J, which is brittle fracture. Since the -10℃ to -70℃, from the impact of performance data and the microscopic morphology observation, DB steel performs better than B＋ steel and 20ГФЛ steel. The conventional mechanical properties and low temperature impact properties of DB steel perform better than mechanical performance index of the steel of bolster and side frame, compared with B＋ steel and 20ГФЛ steel, the low temperature impact properties are better.