How to Spray Lime

1. The problem of billet sticking in the furnace: when cutting precision becomes a risk

In the steel and metalworking industry, machine quality has grown enormously in recent years. Modern sawing machines can produce extremely precise cuts, with regular, almost perfectly smooth surfaces. A result that, on the surface, should only bring advantages. In reality, this very geometric perfection hides a serious and often underestimated operational pitfall: the risk of billets sticking together during heating in the furnace.

When billets with very regular cut surfaces are stacked and fed into the heating furnace, their contact faces find themselves in an almost ideal condition for triggering adhesion phenomena. The result is something operators know well: the pieces arrive “in a block,” stuck to one another, making regular feeding of the downstream line impossible or difficult.

This problem manifests itself through three direct and measurable consequences:

• Uneven heating of the billets, with thermal gradients that compromise the quality of the finished piece.
• Pieces falling “in a block,” with risks to operator safety and damage to the equipment.
• Continuous jams in automatic lines, with production stoppages that directly translate into economic losses.

For production managers and process engineers running highly automated plants, this kind of stoppage is not just an inconvenience: it is a real, repeated, predictable, and preventable cost.

2. What physically happens during heating

To understand why the lime-based solution works, it helps to briefly understand the mechanism that creates the problem. When two smooth metal surfaces come into contact under pressure and in the presence of heat, a process technically known as solid-state welding or surface sintering is triggered: it is more intense the smoother, cleaner, and more geometrically matched the surfaces are.

Here is the industrial paradox: the modern sawing machine works so well that it creates the optimal conditions for this type of adhesion.

The solution cannot be “cutting worse”: it must be interrupting the direct contact between the surfaces before they enter the furnace.

3. The solution: Die Lubrication Solutions’s lime-water spraying system

Die Lubrication Solution (DLS) has designed and built a system specifically conceived to eliminate the billet-sticking problem at its root. Before the billets enter the furnace, a controlled mixture of lime and water is applied directly to the cut surface of each piece.

The thin layer of lime deposited on the surface acts as a physical and chemical barrier. At high temperature, lime does not behave like a metal: it does not diffuse, does not form metallurgical bonds, does not adhere. On the contrary, it remains as a stable separating layer, effectively preventing the two contact faces from “talking” to each other during heating.

The process is fully automated and integrated into the production line. It requires no manual intervention from operators, does not interrupt the production flow, and does not alter the piece’s metallurgical characteristics in any way, which remain compliant with quality specifications.

4. The heart of the system: Aircom atomizers for millimetric spraying

The technological key that makes the DLS system precise, reliable, and economical in product use is represented by the atomizers supplied by Aircom. These components are responsible for turning the lime-and-water mixture into an extremely fine mist, distributed uniformly over the target surface of the billet.

The choice of atomizers is not a minor detail: it is a decisive element for the performance of the entire system. An atomizer of insufficient quality produces irregularly sized droplets, wasted mixture, uneven surface coverage, and potential clogging in the feed circuit. Aircom, with its long experience in industrial spraying, supplies atomizers designed to operate in harsh environments, with controlled pneumatic pressures and calibrated dispersion that ensures optimal coverage with minimal product consumption.

Spraying precision translates directly into:

• Reduced lime waste, with economic benefits on product consumption.
• Uniformity of the protective barrier across the entire cut surface.
• Absence of localized buildup that could interfere with subsequent processing operations.
• A cleaner plant, with less deposit on surrounding structures.

The partnership between Aircom and Die Lubrication Solution stems precisely from the complementary nature of DLS’s expertise in designing lubrication and anti-sticking systems, and Aircom’s expertise in high-precision industrial atomization technology.

5. The concrete benefits for your automatic line

Anyone working on automated production lines knows that every stoppage has a cost that goes well beyond lost machine time. There is the cost of restarting, of checking process parameters, of staff deployed to resolve the jam, and in some cases of damaged or reworked material.

Adopting the DLS anti-sticking system with Aircom atomizers produces measurable benefits on multiple levels:

• Uniform, controlled heating: by eliminating sticking, each billet is heated individually, reaching the target temperature evenly across its entire section. This directly improves the metallurgical quality of the semi-finished product and the dimensional consistency of the finished product.
• Steady arrival rate of hot pieces: the downstream line receives pieces at the regularity expected by the production cycle. There are no slowdowns, buildups, or interruptions related to “blocks” of stuck pieces.
• Significant reduction in line stoppages: this is perhaps the most direct and quantifiable benefit. Automatic lines, which by definition cannot tolerate unplanned interruptions, achieve noticeably higher OEE (Overall Equipment Effectiveness) levels.
• Greater production continuity: a stable process translates into more reliable planning, better predictability of production volumes, and reduced operational stress for shop-floor staff.
• Improved reliability of the heating process: with the lime barrier, the furnace operates under the conditions it was designed for, without experiencing load variations or interruptions related to managing stuck pieces.

6. Why choose lime spraying over other solutions

Over the years, the industry has tried various strategies to address the billet-sticking problem. Some companies have tried to intervene in the cutting process, accepting less precise surface finishes. Others have modified furnace loading programs, reducing the number of stacked billets. Still others have adopted manual physical separators, with obvious problems of time, cost, and safety.

Lime spraying establishes itself as the technically and economically superior solution for several reasons:

• It does not compromise cutting quality: the sawing machine can continue operating at maximum performance, producing surfaces as precise as required by the product’s technical specification.
• It is fully automatic: once the DLS system is installed, no recurring manual intervention is required. The process is integrated into the production cycle and operates in sync with the line.
• The product is economical and safe: lime is an abundant, low-cost, chemically stable, and non-hazardous material. It introduces no contamination into the metallurgical process and poses no disposal or hazardous-substance management issues.
• It is scalable and adaptable: the system can be configured for different billet formats, different production throughputs, and different furnace types, making it suitable for very different production contexts.

7. Conclusion: protect production continuity before the problem occurs

The problem of billet sticking in the furnace is one of those phenomena that tends to be managed reactively: people wait for it to happen, then they intervene. This logic carries an enormous hidden cost, made up of unplanned stoppages, equipment wear, operational stress, and loss of quality in the finished product.

The solution proposed by Die Lubrication Solutions, with its lime-water spraying system and Aircom’s atomization technology, reverses this logic: the problem is eliminated before it even occurs, with a modest investment and a measurable return already within the first production cycles.