Analysis on mechanism of axial drifting of cylinder workpiece on welding roller bed

The basic theory of the axial drifting of the cylinder on a welding roller ded is introduced in the the paper,at,the same time,experiment and study for the mechanism of axial drifting of the cylinder have been done on an experimental of the welding roller bed.It shows that the main cause of the axial drifting of the cylinder lies in the existence of spiral angle between cylinder and rollers.the relative axial motions between rollers and cylinder are composed of spiral motion,elastic slide and frictional slide.The theory of the compatible motion and the non-compatible one is put forward for the exial motions of the cylinder.The relative axial motion between rollers and cylinder is coordinated by elastic slides and frictional slides between two ones.

AZ33M镁合金激光熔覆Al-Si涂层的组织与性能

利用激光熔覆技术在AZ33M镁合金表面制备了Al-Si涂层,通过采用腐蚀电化学测试结合X射线衍射仪(XRD)、扫描电镜(SEM)及显微硬度计等对熔覆层微观组织和性能进行了表征。结果表明,熔覆层主要由Mg和Mg_(17)Al_(12)、Mg_(2)Si及Mg_(2)Al_(3)相组成。熔覆层显微组织由柱状树枝晶和方向各异的树枝晶组成。由于第二相强化和细晶强化等原因,制备的Al-Si涂层相比镁合金基体具有更高的硬度。熔覆层的自腐蚀电位相比基体提高了约400 mV,自腐蚀电流降低了一个数量级,熔覆层的耐蚀性明显优于基体镁合金。