How do metalworking burner accessories resist the dual erosion of thermal fatigue and material oxidation?
Publish Time: 2025-09-23
In high-temperature industrial applications such as steel smelting, metal heat treatment, forging heating, and glass melting furnaces, burners are the core device for providing heat energy. The components within these burner accessories, including the nozzle, flame plate, mixing chamber, and ignition electrode holder, are constantly exposed to extremely harsh operating environments. Temperatures can reach over 1200°C, and frequent starts and stops result in intense thermal cycling. They are also exposed to chemical attack from high-velocity gas, air flow, and combustion products. Under these conditions, burner accessories must simultaneously resist both thermal fatigue cracking and high-temperature oxidation corrosion, two "invisible killers," to ensure long-term stable operation.
1. Facing Thermal Fatigue: Addressing the Structural Challenges of Cyclic Thermal Expansion and Contraction
Thermal fatigue is one of the main causes of burner accessory failure. When a burner is started, components rise from room temperature to high temperature within tens of seconds, causing rapid expansion of the metal. After shutdown, they rapidly cool and contract. These cyclical temperature fluctuations generate alternating thermal stresses within the material, which over time can cause microcracks that gradually expand and eventually lead to fracture or deformation. To combat thermal fatigue, modern burner accessories feature optimized geometric designs, such as smoothly rounded chamfers, avoiding sharp corners and sudden changes in thickness, to reduce stress concentration. Finite element thermodynamic simulations accurately predict deformation trends in high-temperature areas, enabling preemptive structural reinforcement or expansion clearances. Furthermore, some key components employ double-walled structures or internal cooling channels, utilizing a small amount of compressed air or water-cooling media to form a protective air film on the wall or dissipate heat, effectively reducing surface temperature gradients and mitigating thermal shock. For example, cooling ducts are often designed around the edges of burner trays, significantly extending their service life under frequent start-stop conditions.
2. Combating High-Temperature Oxidation: Comprehensive Protection from Materials to Coatings
In high-temperature, oxygen-rich environments, ordinary steel rapidly oxidizes, forming a loose oxide scale on the surface. This not only flakes off and contaminates the workpiece but also accelerates the loss of the base metal. Therefore, material selection is the first line of defense against oxidation. Burner accessories are commonly made of heat-resistant alloys. These materials are rich in elements such as chromium, nickel, and aluminum. At high temperatures, they form a dense, stable protective film of chromium oxide or aluminum oxide, effectively preventing further oxygen intrusion into the substrate and achieving "self-passivation" protection. To further enhance oxidation resistance, many accessories also utilize surface treatment technologies. Examples include electroplating or thermal spraying of aluminum/chromium coatings to strengthen the surface oxidation resistance layer; aluminizing to diffuse aluminum into the metal surface; and ceramic coatings, designed for use in extremely high-temperature environments, providing both thermal insulation and corrosion protection. These coatings not only resist oxidation but also reduce carbon deposits and sulfide corrosion, extending cleaning and maintenance intervals.
3. Manufacturing Process Assurance: Precision Molding and Welding Quality
Even with superior materials, premature failure is inevitable without adequate manufacturing processes. Burner accessories are often thin-walled, irregularly shaped parts that require precision casting, CNC machining, or powder metallurgy. Welds are particularly vulnerable, requiring high-precision processes such as TIG welding and laser welding, along with post-weld heat treatment to eliminate residual stress and prevent crack initiation.
Burner accessories may be small, but they carry the weight of high-temperature environments. Through scientific structural design, high-performance heat-resistant materials, advanced surface protection technologies, and precision manufacturing processes, modern metalworking burner accessories are now able to effectively resist the dual erosion of thermal fatigue and oxidation, ensuring thousands of hours of reliable operation under extreme conditions.
