封条式铝合金热交换器氮气保护钎焊失效分析

封条式铝合金热交换器用途广泛、可靠性高，采用氮气保护钎焊具有生产效率高、温度均匀性好、成本低等特点。本研究介绍了封条式铝合金热交换器的结构特点、材料和用途，并介绍了适用于氮气保护钎焊批量生产的钎焊设备、流程、方法和参数。钎焊是产品生产的关键工序，钎焊失效往往导致产品报废，合格率的下降，进而导致成本的上升。本研究把在生产实践中遇到的主要失效模式根据失效件的特点分为顶板变形、零件移位或变形、温度超高或过低、钎缝泄漏等4大类，分别对这各类失效模式产生原因进行了分析，并针对失效模式的根本原因，从钎焊夹具设计、过程管理、钎焊工艺、零件清洁等方面提出了预防与改进措施，在生产实践中取得了良好效果。

Failure Analysis of Plate-and-bar Aluminum Alloy Heat Exchanger during Brazing in Nitrogen

Plate-and-bar aluminum alloy heat exchangers have been widely used because of high reliability. Brazing in Nitrogen atmosphere has high efficiency, good temperature uniformity and low cost. This paper introduced the structure, material and application of plate-and-bar aluminum alloy heat exchangers. This paper also introduced brazing furnace, process, method and parameters which are used in mass production. Brazing is the most important process in manufacture. Brazing failure will result in product failure, and low percent of pass will bring about high cost. So in this paper, the brazing failure modes of plate-and-bar aluminum alloy heat exchangers are defined by four types in manufacture practice: deformation of top plate, parts translocation or deformation, higher or lower brazing temperature, and leakage in brazing gap. The reasons for the four types of failure modes were analyzed. Measures were put forward on brazing fixture design, process management, brazing process and part cleanness, which turned out to be effective.