In the field of sheet metal processing, hot rolling is a common processing method, widely used in the production of metal structural parts in industries such as automobiles, aviation, and construction. However, during hot rolling processing at high temperatures, the metal surface is prone to react with oxygen in the air, forming an oxide scale or oxide layer, which not only affects the appearance quality of the product but may also reduce the mechanical properties and corrosion resistance of the material. Therefore, how to effectively avoid oxidation problems in the hot rolling process of sheet metal becomes a key factor in improving product quality and production efficiency.



The causes and hazards of oxidation



During the hot rolling process, metal materials are heated to high temperatures (usually above 1000℃), at which time the metal surface reacts chemically with oxygen in the air to form oxides such as iron oxide (FeO, Fe₂O₃, Fe₃O₄), forming a dense oxide scale. This oxide scale not only affects the accuracy and quality of subsequent processing (such as stamping, welding, painting) but also increases subsequent cleaning costs. In addition, if the oxide scale is not completely removed, it may lead to defects such as material fatigue and cracks, affecting the service life of the final product.



Common methods for preventing oxidation



1. Controlling the heating environment



Using inert gas (such as nitrogen, argon) as protective atmosphere in the heating furnace can effectively reduce the contact between oxygen and metal, thereby inhibiting the occurrence of oxidation. In addition, some enterprises will also use reducing gases (such as hydrogen) to further reduce the oxygen content in the furnace.



2. Optimizing heating temperature and duration



Avoiding excessive heating temperature and prolonged holding time is an effective means to reduce oxidation. Heating parameters should be reasonably set according to the type and thickness of the material to ensure that they meet the hot rolling requirements without excessive heating.



3. Using anti-oxidation coatings or lubricants



Applying anti-oxidation coatings (such as borax, graphite lubricants, etc.) on the surface of metal can form a protective film at high temperatures, isolating oxygen from direct contact with the metal. This method is widely used in the processing of some precision parts.



4. Improving hot rolling equipment and process flow



Modern hot rolling production lines can be equipped with rapid heating and rapid rolling systems to reduce the exposure time of metal at high temperatures; at the same time, some advanced hot rolling units are also integrated with online cooling systems, which help to reduce the degree of oxidation.



5. Adopting protective atmosphere hot rolling technology



Protective gas is introduced into the sealed hot rolling equipment, and the oxygen content inside the furnace is monitored in real time to ensure that the hot rolling process is always in a low-oxygen environment, thereby effectively preventing the occurrence of oxidation reactions.



Conclusion



With the continuous improvement of manufacturing requirements for product quality, preventing oxidation in the sheet metal hot rolling process is no longer just a surface treatment issue, but also relates to the performance and reliability of the entire product. By optimizing the heating environment, improving process parameters, using protective coatings, and upgrading equipment configurations, it is possible to significantly reduce the risk of oxidation, improve product pass rate and market competitiveness. In the future, with the development of new materials and new technologies, hot rolling processes will achieve greater breakthroughs in energy saving and emission reduction and quality control, bringing broader development space to the sheet metal processing industry.