Definition - What does Chromizing mean?
Chromizing is a type of metallurgical process that involves diffusion of a single or several elements within a base material. The process is mainly composed of saturating through diffusion of predominantly steel or ferrous alloys with chromium.
It is performed to prolong the lifespan of components and tools that are often exposed to corrosion and wear, like in cases of gas corrosion at temperatures higher than 900°C. This technique is widely applied in industries such as:
Corrosionpedia explains Chromizing
Chromizing can be classified depending on the type of its application. There are two primary types:
- Anti-Corrosion Chromizing: This can be applied to alloys that contain carbon under 0.2 wt% so that the chance of increasing corrosion as well as oxidation or high temperature resistance can be improved.
- Surface Hardening: This is mostly seen in chromized layers in a solution that is composed of chromium solid solution in iron. This solution is usually obtained from low carbon or iron steel.
This process is widely used since laboratory and field data gathered over many years have shown that chromizing is a superb technique that offers protection to exposed surfaces of industrial components, such as in boilers or the aggressive atmosphere in a recovery furnace.
Chromizing is also reliable in providing resistance to sulfidation and oxidation attacks. In fact, it exceeds many other available protection methods. A surface rich in chromium is highly immune to many issues that afflict other forms of protective systems, like spailing and debailing as seen in many coating forms. A chrome layer is non-porous and prone to flaking as well as thermal fatigue.
This process can be applied to smelt sprouts so that these can provide superior performance and optimal life cycle. Another good application is on bank bottles or tube ends. The impressive qualities of chromium are achieved through the metallurgical bond that exists between substrates metal and diffused chromium. This gives the best protection despite mechanical, electrochemical and chemical impact. Having this process coating applied will yield the best corrosion and wear protection to various components.
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