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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 bolster and sideframe steel of railway wagon were studied through microstructure observation, mechanical property test and microscopic fracture observation. The optimal steel grade was selected for the alpine region and the national railway wagon. Charpy V port impact test showed that with the temperature decreased, the impact properties of the material decreased. Temperature dropped to -30 ℃, low-temperature impact strength of Class B steel was 33 J, impact fracture morphology of ductile fracture and brittle fracture each accounted for 50%. The impact energy of B + steel is 28 J, and the fracture morphology is similar to that of low-temperature grade B steel. The impact energy of 20ГФЛ steel is only 12 J, mainly brittle fracture. When the temperature dropped to -60 ℃, the impact energy of low-temperature class B steel was 13 J, which was mainly brittle fracture, but still had very few ductile fracture. The impact energy of B + steel and 20ГФЛ steel is only 12 J, 4 J, which is brittle fracture. From -10 ° C to -70 ° C, low temperature grade B steels were found to be superior to B + steels and 20ГФЛ steels from impact performance data to microscopic fracture observations. The mechanical properties and low-temperature impact properties of low-temperature grade B steels exceed the mechanical properties required for bolsters and sideframe steels, and their low-temperature impact properties are better than those of 20 and 4 steel.