tyhjiöjuottaminenbrazing

Tyhjiöjuottaminen, also known as vacuum brazing, is a specialized joining process used to create high-strength, leak-tight joints between metals. It involves heating the assembly to the melting point of a filler material in a controlled vacuum environment. The vacuum prevents oxidation and contamination of the base metals and filler material, ensuring a clean and pure joint.

The process typically begins with preparing the parts to be joined and applying a filler material, often in a paste or wire form, to the joint area. The assembled parts are then placed into a vacuum furnace. The furnace is evacuated to a very low pressure, typically in the range of 10^-4 to 10^-5 torr. The temperature is then gradually increased to the brazing temperature, which is above the melting point of the filler material but below the melting point of the base metals.

As the filler material melts, capillary action draws it into the closely mating surfaces of the joint. The vacuum environment is crucial here, as it prevents the molten filler from oxidizing and allows it to flow freely into the gap. Once the filler material has fully penetrated the joint, the furnace is cooled back down to room temperature, solidifying the filler and forming a strong metallurgical bond.

Tyhjiöjuottaminen is favored for applications requiring high reliability, excellent mechanical properties, and resistance to corrosive environments. It is commonly used in industries such as aerospace, automotive, medical devices, and electronics. Its ability to create complex, void-free joints with minimal distortion makes it a valuable technique for joining dissimilar metals and for producing intricate components. The absence of flux also eliminates the need for post-brazing cleaning, which can be a significant advantage.