不同基体蠕铁的高温短时拉伸性能及其断裂行为

Elevated Temperature-Tensile Short Strength and its Fracture Behaviour of C/V Graphite Cast Iron With Different Matrix

对三类不同基体的蠕铁(铸态奥-贝蠕铁、普通铁素体蠕铁、等淬贝氏体蠕铁)于200～600℃进行了短时拉伸强度试验,展现了机械性能随温度升高变化的趋势;同时对它们相应温度下的基体、形貌和断口特征等用光镜和SEM进行了对比观察,揭示出其断裂的机制。综合分析了三类蠕铁的温度-机械性能-组织-断口之间的对应关系。文中提出“温—强”比((σ_b^1)/(σ_b))概念,用以表征材质抗温度——机械作用能力的优劣品质。给出三类蠕铁材质良好工作的临界温度。

Short time tensile tests of C/V graphite cast iron with 3 kinds of matrixes (cast austenite-bainite, ferrite, isothernal bainite) conducted in the range of temperature from 200℃ to 600℃ show that the tendency of mechanic properties of those irons varying with temperature rising. In comparison study with their matrix structures, matrix fracture feafure produced at relative temperature by optical microscope and scanning electron microscope, the fracture machnism of the materials is revealed. The relationship among temperature, mechanic properties, microstructure and fracture of 3 kinds of C/V graphite cast iron is comprehensively analysed. Fihally, a new concept temperature-strength ratio ((σ_b^1)/(σ_b)) has been developed to specify the resistant capacity of temperature mechanical action of the materials. Critical temperatures are also given below which the materials can work porperly