Month: May 2020

Stainless steel passivation is the chemical process that removes free iron from the surface of stainless steel for the purpose of enhancing corrosion resistance. Allegheny Surface Technology (AST) offers either citric or nitric acid passivation based on your specific requirements. Metal passivation is but one of several pretreatment steps available for preparing an article for further processing such as electropolishing, or to perform a superior cleaning operation on welded structures.

Passivation creates a chromium rich surface which can form an invisible inert (passive) oxide layer as soon as it is exposed to an oxygen-containing environment (air).

Passivation will not change the appearance of the stainless. If the stainless has been heat treated or welded, the resulting scale or discoloration must be removed by either abrasive methods or by pickling. Passivation will not cause any change to the surface roughness. To verify the effectiveness of the passivation, Allegheny Surface Technology applies saline, copper sulfate, and ferroxyl testing to ensure a successful passivation.

Have more questions? Feel free to contact one of our Passivation specialists by calling (866) 266-9293, or Request a Quote right here on our website.

Recently Allegheny Surface Technology performed critical services On-Site at two large Biotechnology companies. The services and benefits are as follows:

» AST performed de-rouging and passivation on exterior surfaces of the customer supplied stainless steel equipment. The work was performed on a variety of parts including tanks, mezzanines, skids systems, countertops, benches, etc.  These services help prevent any cross-contamination from the exterior of the equipment to get into the product being produced and prolong the life and visual appeal of the equipment.

» Mechanically polished and passivated the interior of a parts washer. This service prolongs the life of the equipment.

» Mechanical polished five tanks to remove scratches and returned the interior surface to a required 20Ra or less. This process was followed by electropolishing and citric passivation of all interior surfaces. These services brought the tanks back to a better standard for operation and allowed the customer to visually inspect abnormalities in the tanks.

» Multiple code weld repairs consisting of the following:

» A tank alteration project to modify a large 10,000-gallon WFI holding tank. The WFI tank alteration project consisted of adding seven different size ports to a pressure-rated tank with an insulated jacket, ports ranged from 2” up to 6”. The modifications to the WFI tank allowed a central distribution to the whole facility. The additional ports were necessary to add distribution loops.

» Hinge repair for a manway. The Hinge repair was to prevent the manway lid from breaking off and causing an injury. A stopper was also installed to prevent the lid from opening too far.

» Repaired a leak on an autoclave. The repair on the autoclave ensures the pressure in the steam jacket and the heat in the autoclave are easily maintained.

At Allegheny Surface Technology, we recognize the importance of these critical services to our customers. We are aware that this is a partnership that relies heavily on each other, and when executed to its fullest potential, will ensure a successful future for both parties.

Have more questions? Feel free to contact one of our On-Site specialists by calling (866) 266-9293, or Request a Quote right here on our website.

Mechanical polishing is the mechanical smoothing and removal of contaminants. It involves grinding, polishing and buffing of the surface. This process is used to smooth out welds, prepare metal surfaces for electropolishing or provide a surface with a specified roughness.  Allegheny Surface Technology (AST) employs experienced and highly skilled craftsmen who have the training and certification to perform this service at any facility.

Our state of the art polishing facility and equipment enable us to consistently achieve your surface requirements, as fine as single digit R_a readings. We are able to work on OEM parts as well as refurbished used vessels and equipment in-house and on-site. Allegheny Surface Technology can also perform compound – free mechanical polishing, a requirement in several pharmaceutical applications.

The techniques available are:

• Abrasive belt polishing
• Abrasive wheel polishing including nylon, flap and combination wheels
• Automated and hand polishing equipment
• Custom machinery for OD and ID polishing of tubular work pieces.

Electropolishing is an electrochemical process that smoothes the surface by removing the peaks on a nanoscopic level (anodic leveling). This enhances the corrosion resistance of austenitic stainless steels, and in some applications also reduces product adhesion and contamination buildup. Electropolishing may also be used for deburring and dulling sharp edges. The result is often a lustrous and reflective finish.

Which is better? Electropolishing:  The CLEAR advantage

Electropolishing typically creates a bright, smooth, and more highly corrosion resistant, sanitary finish. Other advantages of electropolishing include:

• Reducing the surface area on a microscopic level. This reduces product adhesion and contamination build-up, and cleaning can be performed more efficiently.
• Electropolishing has been proven to reduce bacterial biofilm build-up and the appearance of rouging.
• De-burring- The electropolishing process naturally has greater current densities at high points and less at low points. Due to the higher current densities at the high points, the burrs are removed at a much faster rate, leading to a smooth clean surface.
• Aesthetics- Through proper electropolishing, the microscopic surface becomes smooth and clean, containing a nickel-chromium enriched surface that results in a lustrous finish. This facilitates a visual inspection since any remaining imperfections will be magnified.

Have more questions? Feel free to contact one of our Mechanical Polishing & Electopolishing specialists by calling (866) 266-9293, or Request a Quote right here on our website.

Passivation of stainless steel is the chemical process that removes free iron from its surface for the purpose of enhancing corrosion resistance. Allegheny Surface Technology (AST) offers either citric or nitric acid passivation based on your specific requirements. Steel Passivation creates a chromium rich surface which can form an invisible inert (passive) oxide layer as soon as it is exposed to an oxygen-containing environment (air).

Stainless passivation will not change the appearance of the metal. If the stainless has been heat treated or welded, the resulting scale or discoloration must be removed by either abrasive methods or by pickling. When AST passivates stainless it will not cause any change to the surface roughness. To verify the effectiveness of the passivation process, Allegheny Surface Technology applies either saline or ferroxyl testing to ensure successful passivation. The highest form of passivation is electropolishing.

AST can handle almost any size and shape parts. If you can’t send it to us, we will come to you. We passivate vessels, pipes, tubing, manifolds, enclosures, frames, and architectural components, just to name a few. Have more questions? Feel free to contact one of our stainless passivation specialists by calling (866) 266-9293, or Request a Quote right here on our website.