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研究了试样类型、试样厚度、比例试样尺寸及切口尖度等因素对普碳轨钢断裂韧性的影响。试验结果表明,用TPB和CT试样测得的断裂韧性值相同,试样厚度B/[K_(IC)σ_0.2]~2不需要2.5,只要满足2即可测得有效的k_(IC)值;采用10×20×80mm小尺寸TPB试样,P_(max)/P_L虽已超出ASTM E399-82标准的要求,但K_(max)值与K_(IC)值十分接近。切口根径对共析轨钢和亚共析轨钢K_(IC)(ρ)的影响很不相同,可以直接用ρ_0=0.06mm细切口试样测定共析普碳轨钢的K_(IC),因为ρ增加时,K_(IC)(ρ)基本不变。当磷含量低于0.02％时,K_(IC)随磷含量降低有明显提高,但当磷含量高于0.028％时,适当的增加磷含量和降低碳含量,断裂韧性值基本上维持在原有水平。
The effects of sample type, sample thickness, ratio of sample size and notch sharpness on the fracture toughness of carbon rail were studied. The experimental results show that the fracture toughness values measured by TPB and CT specimens are the same. The thickness of specimen B / [K (IC) σ_0.2] ~ 2 does not need to be 2.5, so long as satisfying 2, the effective k_ ) Value of P × (max) / P_L of 10 × 20 × 80mm small size TPB specimens was beyond the standard of ASTM E399-82, but K max value was close to K IC value. The influence of the root diameter on the K_ (IC) (ρ) of the eutectoid steel and the eutectoid steel is very different. The ρ_0 = 0.06mm fine incision specimen can be used to determine the K_ (IC) , Because ρ increases, K_ (IC) (ρ) basically unchanged. When the content of phosphorus is less than 0.02%, K_ (IC) decreases obviously with the decrease of phosphorus content. However, when the content of phosphorus is higher than 0.028%, the content of phosphorus and the content of carbon decrease appropriately, and the fracture toughness basically remains at the original level .