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

在第一个项目阶段，通过选择性表面结构化影响液体淬火的可行性已经得到证明。成功地导出了金属构件的表面结构，发现增加传热表面积是一个重要的机理。因此，表面结构化结果的新策略。到目前为止，深表面结构已被预期，其尖端应在液体淬火期间穿透蒸汽层。在第二个项目阶段，重点应放在具有大传热表面积的光滑表面结构上。这也将简化表面结构在部件制造中的集成，因为可以使用更小的材料余量。真实的部件不能呈现高度圆化的边缘，以减少尖锐边缘对液体淬火的叠加影响。但通常，真实的组件会显示出略微圆化或倾斜的边缘。应研究边缘必须倒圆或斜切到何种程度，以允许液体淬火的有效表面结构化。表面结构化可以加速液体淬火期间的再润湿，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，应将表面结构的方向作为一个附加参数进行研究。重点应放在平行于再润湿方向的结构上。通过选择性表面结构化对液体淬火的影响的可行性已经在圆柱体上得到了证明。对于具有不同横截面的部件，预期表面结构化具有特定的优点。在厚的横截面中，淬火可以加速，而在薄的横截面中，淬火可以通过表面结构化来减慢。这将导致更均匀的淬火，从而降低残余应力和部件变形。钢的表面结构化已经成功，但铝合金的表面结构化并不那么成功。相反，选择性阳极氧化是一种有前途的工艺，应研究铝合金。

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.