Passivation of Piping and/or Equipment
Stainless steel corrosion (i.e. rouge, galvanic, pitting, intergranular, stress, etc.) is an industry-wide problem that, left untreated, can cause problems with equipment cleaning and validation, equipment downtime, reduced equipment life, and product contamination. Chemical passivation is the process in which the stainless steel surface is exposed to an acid in order to remove exogenous iron and to increase the chromium to iron ratio, providing a thicker passive layer to ensure optimal corrosion resistance.
Allegheny Surface Technology will mobilize to your facility with our highly trained technicians to provide complete turnkey services including quality chemical cleaning and passivation to installed systems: pre-operational, pre-commissioning of new construction, recommissioning of old equipment, post modification, preventative maintenance and shutdowns.
Passivation of Newly Installed Equipment
Is a flawless start-up important to you? Pre-commissioning passivation is a critical step in maximizing the essential corrosion resistance of parts and components machined from stainless steel. It can make a difference between satisfactory performance and premature failure.
Although plants are erected utilizing all new equipment and materials, the components typically contain foreign deposits such as milling oil, rust, construction debris, weld spatter, dirt or even sub-surface contamination like chlorides or fluorides that can directly affect metallurgy and alloys during operation or under stressful conditions. If not removed, these foreign particles can reduce effectiveness of the original protective film. Passivation is needed to maximize the natural corrosion resistance of the stainless steel.
Passivation Standards
- ASTM A967
- ASTM A380
- ASTM B912
- ASTM B600
- ASTM B912
- SAE AMS2700
- ASME BPE
- QQ-P-35C (replaced by ASTM A967)
| Service | Description | Benefits | Application Scenarios |
|---|---|---|---|
| Citric Acid Passivation | The use of citric acid solution for circulation or immersion and/or citric acid gel for vertical situations. Both forms meet ASTM A967 specifications. |
|
Installation of new piping or equipment needs passivation to improve clean-ability and the life of the part. Also performed as a preventative maintenance and scheduled to be done on a regular basis. |
Summary
It is essential that your stainless steel systems and equipment are correctly cleaned and passivated before going into service. The cost of pre-commissioning passivation is much less than the costs associated with replacing corroded parts or failed product batches should the system be put into service without prior passivation. Routine cleaning and re-passivation should also be a part of your planned preventative maintenance. Frequency will vary depending upon the use and design, but needless-to-say, high-purity water systems in particular are corrosive and over time, will tarnish the system. A scheduled passivation process will keep the system in optimal condition and prevent (harder to resolve) issues such as rouging.