Annealing for Aluminum Coils
Aluminum coil annealing with a nitrogen atmosphere eliminates the risk of explosion due to the volatilization of rolling oils. Nitrogen also ensures that the surface of the aluminum is not oxidized during annealing, and it can help eliminate staining, which can occur when rolling oils oxidize on the metal surface–causing rejects. Consistent and improved atmosphere quality also results in less edge oxidation, increasing metal yield.
Nitrogen has become the preferred coil annealing atmosphere vs. exothermic-generated atmospheres, which are toxic (contain CO) and combustible, and have the potential for high maintenance costs and production losses due to breakdowns.
Air Products can recommend the optimal nitrogen supply option–including flow rate, purity and supply mode–for your specific aluminum coil annealing operation needs. We can design a system to regulate flow rate, with alarms for oxygen level deviations, for optimization of your process and nitrogen utilization.
Oxygen concentrations controlled below explosive limits of air-fuel mixture
Essentially no downtime associated with liquid nitrogen supply or on-site gas generation with liquid backup
High nitrogen flow only during critical times, in situ oxygen analysis and closed loop feedback control
Consistent atmosphere quality with data collection and leak detection capabilities
Nitrogen atmospheres for coil annealing have significant benefits and advantages vs. exothermic-generated atmospheres, including:
- Improved process control for more consistent product quality
- No upfront capital required
- No maintenance
- No downtime
- Lower safety risk
- No specialized operator training required
- Flow peaking capability for rapid furnace purging (decreased cycle times)
- Elimination of soot buildup, resulting in cleaner furnace interiors
- More available floor space in furnace area
PRISM® Cryogenic Nitrogen Generators
Our range of nitrogen generators includes cryogenic, adsorption, and membrane technologies. We can meet all typical flow, pressure, and purity requirements, providing a highly reliable gas supply at overall cost savings compared to delivered liquid nitrogen.
Count on Air Products’ expertise…
Let us help you determine how to maximize the benefits of nitrogen atmospheres in your coil annealing process.