Delmet stainless steel excellence since 1949
DEROUGING
Rouging is a form of corrosion of stainless steel. The stainless steel derouging treatment ensures the correct removal of the rouge on the metal surfaces through the application of specific products with neutral pH.
THE PROBLEM
Rouge: what does it look like?
IN WFI SYSTEMS
Within WFI systems, especially in the pharmaceutical industry, rouge is visible as layers of reddish coating.
IN STEAM CIRCUITS
In the steam circuits rouge stratification is caused by a rather dark iron oxide coating which is concentrated mainly inside the fittings and in other areas of the circuit.
IN WATER CIRCUITS
In water circuits, a red or red-brown coating generally develops and settles or deposits on the inside of the pipes.
THE FACTORS
Rouge: what causes it?
Rouging is caused by various factors such as a low percentage of oxygen combined with high temperatures..
The higher the temperature in the system, the more the iron oxides multiply. The protective film is in a dynamic chemical equilibrium which can be altered if high temperatures induce an increase in the formation of iron oxides by sacrificing chromium oxide.
The risk of rouging increases if there has been inadequate passivation, incorrect welding with low quality material, the presence of oxides or other treatments performed on the surface.
THE RISKS
Rouge: why it needs to be eliminated immediately
Rouge affects stainless steel surfaces, causing contamination and the proliferation of bacteria on the surface. With derouging, the rouge is removed by means of specific chemical action. With a quick and professional intervention, your systems are as good as new.
ROUGE IN YOUR PLANTS ENTAILS SERIOUS RISKS:
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CONTAMINATION CAUSED BY OXIDISED HEAVY METAL PARTICLES.
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MICRO-CORROSIVE ATTACKS ON STAINLESS STEEL SURFACES
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PREDISPOSITION TO THE PROLIFERATION OF BACTERIA ON THE SURFACE BIOFILME
If the rouge sticks to the metal surface, it can become detached and be carried by the liquid flow through the system in the form of particles that can contaminate the product.
In the pharmaceutical and biotech manufacturing sector, this leads to the loss of sterility and is absolutely unacceptable.
Cleaning, derouging and repassivation are essential to ensure acceptable operating conditions.
SOLUTION
Derouging: the decisive answer to the rouge problem
DEROUGING ACTS ON THE ROUGE LAYER TO CHEMICALLY REMOVE IT AND THUS AVOID CONTAMINATION OF THE CIRCUIT AND THE PRODUCTS IT CONTAINS.
We work quickly and professionally with highly qualified operators to restore your systems.
We use chemicals that do not damage the stainless steel of your plant and can therefore be used periodically without deteriorating the surface.
90
TRADITIONAL METHOD
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• REMOVAL OF HEALTHY MATERIAL
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• HOW MANY TIMES CAN THE TREATMENT BE REPEATED IN THE PLANT: 4/5
100
DELMET METHOD
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PRESERVATION OF HEALTHY MATERIAL
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• HOW MANY TIMES CAN THE TREATMENT BE REPEATED IN THE PLANT: INFINITE
We analyse the iron content in the solution used to tell you what we have eliminated.
We verify successful passivation using the ferrocyanide test.
The certification of derouging to validate results is included in the service.
Regular checks and maintenance are essential to prevent the rouge from forming again.
WHY CHOOSE US
WE REMOVE ROUGE 100% EFFECTIVELY:
The steps: We carry out several steps to obtain a highly satisfactory result and restore the implants to their original state.
- Degreasing
- Rinsing
- Derouging
- Rinsing
- Repassivation
- Flushing
Degreasing and passivation are performed in compliance with ASTM regulations, while derouging is continued until the chemicals used are completely exhausted.
DEROUGING
It is not unusual for rouging to affect the surfaces of stainless steel. Rouge is visible as layers of reddish coating on stainless steel surfaces within pharmaceutical equipment and loops. Even the main stainless steel pipe systems used in the pharmaceutical and biotech industries cannot escape the attack of rouge. In most cases, within WFI systems rouge is visible as layers of reddish coating, while in steam circuits the rouge stratification affecting the surface is quite dark and is mainly concentrated inside the fittings.
Rouge particles can also be present in other areas of the circuit and therefore can be removed by flushing the product within the system. The problem of rouging should not be underestimated, especially in the "clean" pharmaceutical sector. Rouge can be removed with innovative pH-neutral products that do not damage the equipment and can therefore be repeated periodically without damaging the workpiece.
The passivation of new systems
is a very important way to prevent rouging, but its protection does not last forever. Various factors, such as a low percentage of oxygen combined with high temperatures, can lead to the formation of rouging. The only method to restore the surface is to perform normal derouging with a non-aggressive neutral product and re-passivate the system.
Problems caused by rouge:
- Oxidised heavy metal particles that cause contamination
- Micro-corrosive attacks on stainless steel surfaces
- Predisposition to the proliferation of bacteria on the stainless steel surface biofilm
CONTRACT DEROUGING
DEROUGING TREATMENT
To combat rouging, you can rely on Delmet's contract service dedicated to the derouging of stainless steel.
Delmet is able to definitively solve the problem of rouging, thanks to a special process that does not damage the healthy material and can therefore be repeated cyclically, with no limitations on the maximum number of treatments.
The entire process involves several phases, all of which can be carried out at our factories: the steel products must be prepared for derouging with degreasing and rinsing, then a second rinse is carried out before the final stages of repassivation and flushing.
Regular checks and maintenance are essential to prevent the rouge from forming again.
Electrolytic Metal Deoxidation
Limitless solutions for the surface treatment of stainless steel
DO YOU NEED OUR SERVICES?
Delmet is able to solve any query and problem related to the surface treatment of stainless steel.It offers contract processing, design and manufacture of customised plants, formulation and sale of chemicals and machines for the purification of process water and air treatment.
If you need more information or want to speak to one of our managers, fill out the request form and you will be contacted shortly.