| 摘要 |
<p>In a batch- or continuous-process to solder the component parts of an automotive metal heat exchanger, the pre-assembled parts are located within sleeve within a heated chamber. The sleeve is continually flushed with an enhanced flow rate of inert gas or reaction gas. The oxygen content of the atmosphere within the sleeve is well below 500 ppm. The metal is aluminum, aluminum alloy or wrought alloy. The soldering process takes place without the use of a flux agent. The rate at which the heated chamber is flushed with gas is greater than 250 m(3/hr/m(3 oven. The inert gas or reaction gas is a noble gas from the eighth main group of the periodic table, or hydrogen, nitrogen, carbon dioxide, carbon monoxide, ammonia and/or gases cracked from natural gas. The oxygen content in the soldering zone is considerably less than 40 ppm. The soldering process takes place at temperatures above 300[deg]C. The dew point in the heated chamber is less than -45[deg]C. During the oven heat-up process the temperature is maintained between 400 and 615[deg]C for a minimum period of three minutes.</p> |
