共查询到19条相似文献,搜索用时 109 毫秒
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从力学性能、化学成分、金相组织等方面进行对比试验,分析30MnSi盘圆加工成的管桩用PC钢棒镦头发生脆断的原因,提出工艺改进措施。 相似文献
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从盘条和管桩生产工艺等方面,分析30MnSi管桩钢筋镦头开裂的原因,认为除传统上的钢筋热处理和盘条钢质两类影响因素外,表面划伤和折叠等线状缺陷也会造成镦头开裂,对比作重点分析。 相似文献
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含硼冷镦钢SAE10B21在拉拔后镦头成型过程中多次出现开裂,为分析造成冷镦开裂的主要原因,对冷镦开裂试样进行宏观观察、金相组织、非金属夹杂物、描电镜及能谱等检测分析。结果表明:SAE10B21镦头成型开裂的主要原因有连铸卷渣、铸坯裂纹、轧制折叠、轧制划伤、拉拔划伤等五类。 相似文献
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Turgay Ertürk 《Metallurgical and Materials Transactions A》1981,12(5):743-748
The anisotropy of bulk formability in hot-rolled AISI 1040 steel bars has been evaluated using upset and bend tests in longitudinal,
circumferential, and radial directions. The index of workability is improved approximately 65 pct by aligning the critical
tensile stresses parallel to inclusion plane and elongation (longitudinal direction). The lowest workability is attained in
the radial direction where tensile stresses are perpendicular to the plane of inclusions. In the circumferential direction,
tensile stresses are parallel to the plane of inclusions, though perpendicular to inclusion elongation, leading to intermediate
workability. Tensile ductilities in the principal directions are compared with the three workability levels. Tension fracture
data agree with the forming limit line in the radial direction. In the other directions, however, the tension test progressively
overestimates workability as the workability level increases. 相似文献
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φ9.0 mm的PC钢棒在生产过程中时常发生断裂.对断裂的PC钢棒进行宏观(低倍)、化学成分、金相组织及夹杂物检测,发现其组织存在严重的表面裂纹、块状碳化物和夹杂物是引起断裂的主要原因. 相似文献
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为了探究实际生产中非调质钢轧材横向塑性波动较大的原因,利用电子显微镜对比研究了连铸坯、轧材和拉伸试样断口中MnS夹杂物形貌及其演变行为,并对轧材横纵截面MnS夹杂物的尺寸、数量以及分布特征进行定量化表征,发现MnS夹杂物的分布特征是影响轧材横向塑性的关键。MnS夹杂物聚集分布,拉伸试样在受力过程中大量微裂纹在局部同时萌生,导致试样提前断裂,形成木质状的断口形貌,轧材表现出较差的横向塑性。当MnS夹杂物分布较为均匀时,拉伸试样受力相对均匀,应力集中小,轧材横向塑性较好。轧材中MnS夹杂物的分布行为主要取决于铸态下MnS夹杂物的形貌。减少铸态下II类树枝状MnS数量,是改善最终轧材横向塑性的关键。 相似文献
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To investigate the effect of heat treatment on mechanical properties and delayed fracture resistance of high strength steel, 30MnSi prestressed concrete (PC) steel bars are quenched and tempered. Tensile results show that, after 950 °C quenching and about 430 °C tempering, 30MnSi PC steel bars have superior mechanical properties and delayed fracture resistance. Microstructural observation shows that 30MnSi steel bar is mainly composed of fine tempered sorbite (troostite) with carbide distributed along the lath martensite boundaries. It can be concluded that thermal refining is an effective way to improve mechanical properties and delayed fracture resistance of 30MnSi PC steel bar. 相似文献
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