Scaling
Scale formation is the process where metals react with oxygen at elevated temperatures to form brittle oxide layers. This can be reduced by using shielding gas atmospheres.
Physical-Chemical Mechanism of Action
Scale formation is a chemical reaction between metals and oxygen that occurs at elevated temperatures. Metal atoms react with oxygen molecules to form brittle metal oxides. This process can lead to a change in the metal structure.
Metallurgical Relevance & Welding Risks
Scale formation can lead to a coarser grain structure and a reduction in the toughness of the material. Brittle oxide layers can also increase the hardness of the weld, which can lead to hot cracking. Moreover, it can affect welding, as the brittle layers can disrupt the contact between the metal and the shielding medium.
Workshop Practice & Action Instructions
To minimize scale formation, protective gas atmospheres such as argon or helium should be used during heat treatment processes. The temperature and time of heat treatment should be precisely controlled to ensure an optimal grain structure and high toughness of the material.