Load-appropriate arc brazed joint of high-strength sheet steels under metallurgical and geometrical aspects (joint proposal)

电弧钎焊的原理应用可能性与实际应用存在很大差异。这是由于目前对于静荷载和循环荷载作用下弧焊钢板连接失效的认识还不够先进，无法对连接部件进行适当的荷载设计。这种对搭接焊缝几何设计及其局部冶金成分与接头性能之间关系的基本理解应在研究项目的范围内完成。到目前为止，还不可能给出导致钎焊焊缝失效的确切局部过程和失效机制的精确规范。因此，计划研究项目的目标是详细研究影响静态和循环连接强度的主要因素，如钎焊材料强度、附着力、扩散、润湿、几何/力流和基材性能的变化；另一个原因是引用基本失效机制。因此，对破坏原因的更可靠的陈述是可能的，并为合理应用电弧钎焊接头铺平了道路。这一目标应通过数值模拟模型和冶金模型试验来实现。考虑到上述影响因素，将电弧钎焊接头分为与强度相关的几何和冶金各个方面（如间隙填充等），可以单独进行检查。随后，为了确定单个因素对整个钎焊接头强度（静态、循环）的影响，将单个结果再次合并。在固结过程中，还考虑了所研究的影响因素对节理特性的相互作用。研究项目的目标被细分为两个从属的目标。目标1代表实现钎焊接头，其特点是在基材水平上具有较高的静态强度，同时具有良好的循环强度。目标2代表了一个接头的生产，其特点是具有非常好的循环强度，明显高于迄今为止可能的基材载荷的25%，同时仍然具有足够好的静强度。在这里，对两个目标的综合目标要求是高可靠性和低散射结果的再现性。它是，以这种方式，有可能实现一个更可靠和更强的连接，关于主要类型的负载。

There is a great divergence between the principle application possibilities and the real applications of arc brazed joints. This is ascribed to the fact that, currently, the knowledge about the failure of arc-brazed sheet steel joints under static and cyclic load is not advanced enough for carrying out the load-appropriate design of the joined components.This fundamental comprehension of the connections between the geometrical design of the brazed seam on lap joint as well as its local metallurgical composition and the joint properties shall be worked out within the scope of the research project. It has, so far, not been possible to give a precise specification of the exact local processes and failure mechanisms which lead to the failure of the brazed seam. Therefore, the objective of the planned research project is the detailed investigation of the main factors which exert influence on the static and cyclic joint strength, such as braze material strength, adhesion, diffusion, wetting, geometry/force flow and the changes of the base material properties; another reason is to make references to the basic failure mechanisms. Thus, a more reliable statement about the failure reasons is possible and the way for the load-appropriate application of arc brazed joints is paved. This objective shall be achieved by means of a numerical simulation model and also by metallurgical model tests. The arc brazed joint is, under consideration of the above-mentioned influential factors, separated into strength-relevant geometrical and metallurgical individual aspects (e.g. gap filling, etc.) which can be examined separately. Subsequently, the individual results are consolidated again in order to determine thus the effects of the individual factors on the strength (static, cyclic) of the entire brazed joint. During consolidation, also interactions of the examined influential factors on the joint properties are taken into consideration.The objective of the research project is subdivided into two sub-ordinate objectives. Objective 1 stands for the achievement of a brazed joint which is characterised by a high static strength on base material level with, at the same time, good cyclic strength. Objective 2 stands for the production of a joint which is characterised by a very good cyclic strength, clearly higher than the hitherto possible 25% of the load of the base material with, at the same time, still sufficiently good static strength. Here, the integrative target requirement to both objectives is the high reliability and reproducibility of the results with low scattering. It is, in this manner, possible to achieve a more reliable and stronger joint with regard to the predominant type of load.