Astropak

Chemical cleaning and passivation treatments on stainless steel tubing and equipment are an important aspect in the preparation of surfaces used in corrosive and critical environments. The formation of a higher chromium to iron (Cr/Fe) ratio in the passivate layer will result in improved corrosion resistance and lowered rates of iron oxide formation (rouge). Clean process and transfer system surfaces are required to maintainpurity of processes and products. A corrosion resistant surface insures continuous fluidquality with a lack of impurities generated at the stainless steel surface.

The importance of chemical cleaning and passivation of stainless steel has been documented by others in past publications.1,2 The formation of an inert surface is the goal for passivate techniques. Comparative results of various combined chelant processes in addition to nitric acid and electropolished surfaces will be presented. Stainless steel surfaces were treated and then tested with Electron Spectroscopy for Chemical Analysis ("ESCA") and Auger Electron Spectroscopy ("AES") procedures to determine improvements in surface chemistry.

Pickling and passivation results from the formation of a chemically inert surface, which maximizes corrosion resistance. The anodic oxide/hydroxide film is very thin (10 to 50 Angstroms "Å") and high in chromium oxide. Removal of contaminants is critical to the life of the passive layer and the reduction of corrosion. Thus, the benefits of the passivate surface are the increased corrosion protection and contaminant free surface leading to improved system life and purity of process fluids. There exist many physical parameters important in the measurement of a corrosion resistant surface including: surface area (roughness), oxide layer depth, chromium to iron ratio and surface contaminant inclusions. Periodic system inspections and performance of precision cleaning and passivation are required to insure maintenance of the passive layer.

Initial passivation of stainless systems is dictated by a need to repair the activated areas of all welds, as shown by recent research,3 and the need to insure an improved corrosion resistant surface throughout the system. Chemical cleaning and passivation removes the adsorbed and included contaminants that provide sites for pitting corrosion as well as iron, which will evolve into rouge formation.

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From creating a Defect Resolution & Root Cause Analysis Program with a goal of 100% defect-free service quality and performance to having a dedicated Safety Director ensuring safety compliance and advancing a culture of accident prevention, every decision made is made with excellence in mind. Why? Because excellence is standard - a standard never compromised. Every element that affects customers' experience needs to withstand the demands of excellence, right down to the valves and hoses purchased. After all, when your goal is to deliver a service experience not found anywhere else, sometimes the smallest details could have the most profound effects.

What is Passivation?

Passivation of austenitic stainless steel surfaces has been practiced on high purity water systems for many years, and is generally defined as the removal of iron and iron compounds from the surface to improve the passive film and increase corrosion resistance. The surface chemistry, structure and related corrosion resistance of austenitic stainless steel is affected by mechanical polishing, welding, and most fabrication techniques. Nitric passivation reduces or eliminates this damage while forming a more corrosion resistant passive film high in chromium oxide

Astro Pak Capabilities

• Pickling and Passivation
• Ultra Pass® (Citric Acid Chelant) Passivate of Stainless Steel
• Nitric Acid Passivation of Stainless Steel and Other Alloys Precision Cleaning

tag : nitric passivation, passivate, Passivation, Pickling and Passivation

You may have heard of Ultra Pass® passivation. With over 50 years of scientific research behind it, I’d be surprised if you haven't. To chemists, the idea seemed simple: Produce high surface chromium levels creating the best corrosion resistant passivate surface. Through extensive research and development, chemists were able to find the optimal citric acid chelant process, Ultra Pass® and CGA G-4.1 to bring it out of the labs and into the field.

But it didn't stop there. Understanding that field conditions and project requirements can vary considerably, Ultra Pass® was created with built-in versatility for needs requiring individualized solutions. It is through ongoing lab research that chemists are able to continue the heritage of delivering the most advanced passivation processes today and into the future.

Astro Pak Capabilities

• On-site and In-house Services
• Ultra Pass® Citric Acid Passivation of Stainless Steel
• Nitric Acid Passivation of Stainless Steel and Other Alloys
• Pickling and Passivation
• Cleaning and Passivation for Pre-Commissioning, Maintenance, Planned Shutdown and Emergency Outage Projects
• Professional Consulting

Ultra Pass® Passivation Benefits

• Drastically improves surface chemistry
• Restores and protects vulnerable weld and Heat Affected Zones from corrosion
• Exceeds the SEMI F19-95 Cr/Fe, CrO/FeO ratios
• More effective treatment than electropolishing on intricate paths
• Green (eco-friendly) process

Part and System Cleaning Experience

• WFI (Water for Injection)
• Pure Steam and Clean Steam
• Reverse Osmosis
• De-ionized Water
• High Purity Gas and Vacuum
• Product and Process
• Pure Steam Generators
• CIP and SIP Skids and Components
• Autoclave and Isolation Barriers
• Vessels and Tanks
• Fermenters and Bio-reactors

Standards Met

• CGA G-4.1
• ASTM A967
• ASTM A380 Client Protocol Specifications

Disclaimer: This blog or article is for information purpose only, and should not be treated a professional advise or price protection guarantee. This blog is mainly used for search engine optimization and other commercial purposes and it is advised that readers seek professional consultation in the field of interest for more information.

What is Passivation? Passivation is “the removal of exogenous iron or iron compounds from the surface of a stainless steel by means of a chemical dissolution, mosttypically by a treatment withan acid solution that will remove the surface contaminationbut will not significantly affect the stainless steel itself.” In addition, it also describes passivationas “the chemical treatment of a stainless steel with a mild oxidant, such as a nitric acid solution, for the purpose of enhancing the spontaneous formation of the protective passive film.”

Passivation: ASTM 316L stainless steel electro-polished sanitary tubing was used as the substrate. A series of orbital welds were made on a single lot of 1-inch (in) tubing by a single operator using a single welder at constant settings. The reason for the use of a single lot of tubing, as well as welds made in one session by the same operator using the same welder at identical settings, was to control for unmeasured variables that could possibly tend to confound data analysis. After welding, the tubing was then sectioned, using a cold-cut technique. Cold cutting was again used to control for unmeasured changes in surface chemistry that could be caused by heating of the welds during the cutting operation. Samples of the weld, approximately 1/2 –in by 3/8 –in, were created and identified by engraving an alphanumeric identifier on the outer diameter of the samples. Five samples, labeled W70 through W74, were cleaned with a heated alkaline cleaning process.

These non-passivation samples were then individually packaged in clean room grade polyethylene bags. The second set of five samples, labeled W60 through W64, was cleaned with a heated alkaline cleaning process. The set was then passivated at ambient temperature using the gelled Citric acid passivationagent for 120 minutes. The third set of five samples, labeled W65 through W69, was cleaned with a heated alkaline cleaning process. This final set was then passivated at ambient temperature using the gelled citric passivation agent for 240 minutes.

Disclaimer: This blog or article is for information purpose only, and should not be treated a professional advise or price protection guarantee. This blog is mainly used for search engine optimization and other commercial purposes and it is advised that readers seek professional consultation in the field of interest for more information.