How We Solved the Problem of Corrosion in Metal Components in Industrial Washing Lines: A Practical Approach

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In one of our projects, we addressed repeated customer complaints about corrosion of metal parts after passing through an industrial washing line. The problem was particularly evident in parts made of carbon steel and cast iron, where visible surface attack occurred after just a few cleaning cycles. After analyzing the operating conditions and the composition of the cleaning agent used, we found that the key factor was not only the aggressiveness of the cleaning agent itself but also an unsuitable combination of pH, temperature, and the presence of chlorides. How did we proceed in finding a solution, and what adjustments did we achieve?

Problem: Corrosion damage in industrial washing lines

Corrosion damage to metal components in industrial washing lines is a frequent and costly problem that can lead to premature equipment failure, increased maintenance costs, and even operational safety risks. In our case, a customer from the automotive industry faced significant corrosion of stainless steel parts after just six months of using a new washing line. Analysis showed that the cause was not only the material quality but primarily the chemical composition of the cleaning agent used and the operating conditions.

Corrosion processes in washing lines are typically accelerated by a combination of several factors: high temperatures (often 60–80 °C), the presence of chlorides, low pH of the solution, and mechanical stress. In this particular case, the cleaning agent contained aggressive inorganic acids and high concentrations of chloride ions, which disrupted the passive layer on the surface of the stainless steel. An important finding was also insufficient rinsing, which led to the deposition of cleaning agent residues on metal surfaces.

Diagnostics: How we identified the causes of corrosion attack

The first step in solving the problem was comprehensive diagnostics, which included an analysis of operating conditions, the chemical composition of the cleaning agent, and the condition of the damaged components. We performed a visual inspection of corrosion products and a microscopic analysis of the surface, which revealed typical signs of pitting corrosion – small but deep craters in the material. Laboratory tests confirmed a high chloride content in the cleaning solution, which exceeded the recommended limits for stainless steel.

We also mapped the entire cleaning process, including temperature profiles, exposure time, and rinse water quality. We found that the rinse water contained residues of the cleaning agent and had a low pH, which prolonged the contact time of aggressive substances with the metal surface. To verify the impact of individual factors, we conducted a series of corrosion tests according to standard test methods that simulated real operating conditions. The results clearly showed that the key issue was the combination of high temperature, chlorides, and insufficient rinsing.

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Solution: Optimization of chemical composition and operational parameters

Based on the diagnostic results, we proposed a comprehensive solution that included adjusting the chemical composition of the cleaning agent and optimizing operational parameters. The first step involved replacing aggressive inorganic acids with less corrosive organic acids and surfactants with inhibitory properties. We also reduced the chloride concentration below the critical threshold for stainless steel and added corrosion inhibitors that form a protective layer on the metal surface.

Operational adjustments included reducing the washing process temperature from 80 °C to 60 °C, which significantly slowed corrosion reactions without negatively affecting cleaning efficiency. We also extended the rinsing time and introduced quality control of the rinse water to minimize the deposition of cleaning agent residues. To ensure long-term protection, we recommended regular monitoring of the pH and conductivity of the washing solution, enabling early detection of potential issues.

Results and recommendations for preventing corrosion damage

After implementing the proposed measures, corrosion damage to metal components in the washing line completely stopped. Control measurements after three and six months of operation confirmed that the stainless steel surface remained undamaged and the passive layer was preserved. Additionally, the customer recorded a 15% reduction in cleaning agent consumption due to the optimization of concentration and temperature, resulting in further savings.

To prevent corrosion damage in industrial washing lines, we recommend following several key principles: regularly check the chemical composition of cleaning agents with regard to chloride content and pH, maintain an optimal temperature regime, and ensure thorough rinsing. It is also important to select cleaning agents with inhibitory additives and monitor the quality of rinse water. In case of doubt, it is advisable to perform corrosion tests according to standard methods, which will help identify risk factors and prevent costly repairs.

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Selecting Suitable Corrosion Inhibitors for Specific Metal Materials

Corrosion processes in industrial cleaning lines often require an individual approach, as different metal materials react differently to the chemical composition of cleaning solutions. For example, carbon steel is prone to uniform corrosion, while stainless steel may suffer from pitting corrosion in the presence of chlorides. When addressing the issue, we first conducted an analysis of the material composition of the affected components and then selected suitable corrosion inhibitors. For carbon steel, organic inhibitors based on amines or phosphonates proved effective, as they form a protective layer on the metal surface. For stainless steel, we focused on inhibitors containing nitrogen or sulfur, which effectively block active sites prone to pitting corrosion.

An important factor in selecting inhibitors is their compatibility with other components of cleaning agents. For instance, a strongly alkaline environment can reduce the effectiveness of some inhibitors, while the presence of chelating agents may, on the contrary, enhance their action. In our case, we tested various combinations of inhibitors with surfactants and complexing agents to achieve an optimal balance between cleaning efficiency and corrosion protection. The result was a formulation that not only effectively removed dirt but also extended the service life of metal components by more than 50%.

Optimization of Operational Parameters in Cleaning Processes

In addition to the chemical composition of cleaning agents, operational parameters such as temperature, exposure time, and mechanical action also play a key role. While high temperatures increase cleaning efficiency, they simultaneously accelerate corrosion processes, especially in metals sensitive to thermal stress. In our case, we found that reducing the temperature of the cleaning solution from 80 °C to 60 °C led to a significant reduction in corrosion without compromising cleaning performance. This step was made possible by optimizing the concentration of surfactants and alkaline components, which compensated for the lower temperature.

Another critical factor was the exposure time of metal components in the cleaning solution. Prolonged contact with aggressive chemicals increases the risk of corrosion, particularly in components with complex geometry where solution accumulation occurs in recesses. The solution involved implementing precisely timed cleaning cycles and modifying the design of the cleaning nozzles for better solution drainage. Regular monitoring of the pH and conductivity of the cleaning solution also played a key role, enabling timely correction of inhibitor concentrations and other active components.

Monitoring and Maintenance as the Key to Long-Term Protection

Even after implementing optimised cleaning agents and operational parameters, it is essential to regularly monitor the condition of metal components and the quality of the cleaning solution. In our case, we implemented a system of regular inspections, which included visual inspection of components, measurement of metal wall thickness using non-destructive methods, and analysis of the chemical composition of the cleaning solution. These inspections enabled early detection of any deviations and thus prevented more extensive corrosion damage.

An important part of maintenance was also training the cleaning line operators. Staff were trained in the correct dosing of cleaning agents, interpretation of pH and conductivity measurements, and recognition of early signs of corrosion. The introduction of standardised procedures for the maintenance and cleaning of washing lines also minimised the risk of contamination of the cleaning solution with residues of dirt or previous chemicals, which could impair the effectiveness of corrosion inhibitors. Thanks to these measures, it was possible to keep corrosion damage to a minimum and significantly extend the intervals between replacements of critical components.

Do you need to optimize your cleaning processes?

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