Fatigue Resistance of HPS-485W (70?W) Continuous Plate with Punched Holes

Twenty-nine specimens were tested to investigate the fatigue resistance of high-performance steel (HPS-485W) (70?W) continuous plate with punched holes. Specimen thickness, hole diameter, and method used for creating the holes were varied to examine their effect upon fatigue resistance of punched connections utilizing high performance steel. Eight of the 29 specimens were drilled or subpunched and reamed specimens, all of which rated as Category B details. The remaining 21 specimens had punched holes and rated considerably below a Category B. Results from this investigation suggest that current restrictions mandated by some state DOTs concerning punching holes are not overly restrictive when HPS-485W (70?W) is utilized. Performance of drilled and subpunched and reamed specimens met (or exceeded) 2004 AASHTO requirements for Category B details.     

梯度结构W(Mo)-Ni-Fe高密度合金的组织与结构

将93W-4.9Ni-2.1Fe混合粉末压坯经过脱脂预烧、渗钼和脱钼处理以及烧结,得到W(Mo)-Ni-Fe高密度合金,采用金相分析、能谱分析、显微硬度测试等方法对该合金的成分和微观结构进行分析.结果表明,W-Ni-Fe高密度合金经渗钥处理后形成显微组织、钼含量和镍铁粘结相的梯度分布,其特征是合金表层的粘结相少于芯部:...