Influence on liquid quenching in heat treatment by means of previous surface structuring

在项目的第一阶段，通过选择表面结构来影响液淬的可行性得到了验证。成功地导出了金属部件的表面结构。增加传热表面积是一个重要的机理。从而产生了新的表面结构策略。到目前为止，已经设计了深层表面结构，其尖端应在液体淬火时穿透蒸汽层。在项目的第二阶段，重点是更光滑的表面结构和大的传热表面积。这也将简化组件制造中表面结构的集成，因为可以使用更小的材料余量。真实零件不能呈现高度圆润的边缘，以减少尖锐边缘对液淬的叠加影响。但通常情况下，真正的组件表现出轻微的圆形或斜面边缘。应进行调查，在何种程度上，边缘必须被磨圆或倾斜，以允许有效的表面结构进行液体淬火。表面结构可以加速液体淬火过程中的再润湿，但也会阻碍再润湿，特别是如果表面结构是水平的，即垂直于再润湿方向。因此，表面结构的取向应作为附加参数进行研究。重点应放在与重润湿方向平行的结构上。表明了选择表面结构影响汽缸液淬的可行性。对于具有不同截面的部件，期望表面结构具有特殊的优点。在厚截面中，淬火可以加速，而在薄截面中，淬火可以通过表面结构减慢。这将导致更均匀的淬火，从而降低残余应力和更低的部件变形。钢的表面构造已经成功，但铝合金的表面构造还没有那么成功。相反，选择性阳极氧化是一种很有前途的工艺，值得对铝合金进行研究。

During the first project stage, the feasibility of influencing on liquid quenching by selective surface structuring has been proven. Successful surface structures of metal components have been derived.Increasing the heat transferring surface area has been found to be an important mechanism. Thereof new strategies for surface structuring result. Up to now, deep surface structures have been intended, whose tips should penetrate the vapour layer during liquid quenching. In the second project stage, the focus shall be on smoother surface structures with large heat transferring surface areas. This will also ease integration of surface structuring in component manufacturing, because smaller material allowances can be used.Real components cannot exhibit highly rounded edges, to reduce the superimposed influence of sharp edges on liquid quenching. But often, real components exhibit slightly rounded or bevelled edges. It shall be investigated, to which extent edges must be rounded or bevelled, to allow an effective surface structuring for liquid quenching.Surface structuring can accelerate rewetting during liquid quenching, but also hinder rewetting, especially if surface structures are horizontal, i.e. perpendicular to the rewetting direction. Therefore the orientation of surface structures shall be investigated as an additional parameter. The focus shall be on structures parallel to the rewetting direction.The feasibility of influencing on liquid quenching by selective surface structuring has been shown for cylinders. Particular advantages of surface structuring are expected for components with varying cross sections. In thick cross sections, quenching can be accelerated, whereas in thin cross sections, quenching can be slowed down by surface structuring. This would result in more homogeneous quenching and thereby lower residual stresses and lower component distortion.Surface structuring of steel has been successful, but surface structuring of aluminium alloys has been not that successful. Instead, selective anodic oxidation is a promising process, which shall be investigated for aluminium alloys.