Pickling is a chemical process that removes scale, weld discoloration, oxides, and heavy surface contamination from stainless steel fabrications, typically as preparation before passivation.

What is the difference between pickling and passivation?

Pickling removes scale, weld oxides, and surface damage and does alter the surface; passivation removes free iron and restores the passive layer without changing the finish. Many parts need both, in sequence.

When do I need pickling?

After welding or heat treatment that leaves heat tint and scale, on heavily contaminated stainless fabrications, and before passivation when the surface is too contaminated for passivation alone.

What standards apply to pickling?

ASTM A380 covers cleaning, descaling, and pickling of stainless steel parts, equipment, and systems. Harrison also works to customer-specific requirements.

Passivation is a chemical treatment that removes free iron and surface contaminants from stainless steel and strengthens its naturally occurring, corrosion-resistant chromium-oxide layer. It does not change part dimensions.

What is the difference between nitric and citric acid passivation?

Nitric acid is the traditional, aggressive method effective on heavy contamination. Citric acid is biodegradable and safer for medical, food, and pharmaceutical work while achieving comparable corrosion resistance. Harrison offers both.

When should stainless steel be passivated?

After machining, welding, grinding, or forming; before high-purity service; when customer or industry standards require it; and on a preventive-maintenance schedule in high-chloride environments.

Does passivation change part dimensions?

No. Passivation removes only free iron and contaminants, so there is no measurable change to base-material dimensions.

What standards does Harrison passivate to?

ASTM A967, ASTM A380, ASTM B912 (electropolishing passivation), AMS 2700, and customer-specific specifications, with copper sulfate and ferroxyl testing for verification.

Pickling

Stainless Steel Pickling Services

stainless steel pickling The Pickling process utilizes more aggressive acids than those used in passivation. The acids used when pickling the stainless steel surface can remove or dissolve existing oxidation, weld oxides, embedded particles and scale that can build up on stainless steel during real-world fabrication, welding and handling. Pickling is used extensively to clean and prepare stainless steel fabrications for service within demanding environments. Without pickling, stainless steel fabrications will not resist corrosion as they are engineered to do.

Harrison Electropolishing has performed pickling treatments on corrosion resistant materials with excellent results since 1980. We have the capacity to pickle components of all sizes. Harrison Electropolishing can perform stainless steel pickling / passivation treatments in compliance with ASTM A380 or your industry or company specific chemical passivation standard.

Services: Passivation, Passivation & Pickling, Electropolishing
Industries: Petrochemical, Oil & Gas

More to Know

Frequently Asked Questions

What is pickling?

Pickling is a chemical process that removes scale, weld discoloration, oxides, and heavy surface contamination from stainless steel fabrications, typically as preparation before passivation.

What is the difference between pickling and passivation?

Pickling removes scale, weld oxides, and surface damage and does alter the surface; passivation removes free iron and restores the passive layer without changing the finish. Many parts need both, in sequence.

When do I need pickling?

After welding or heat treatment that leaves heat tint and scale, on heavily contaminated stainless fabrications, and before passivation when the surface is too contaminated for passivation alone.

What standards apply to pickling?

ASTM A380 covers cleaning, descaling, and pickling of stainless steel parts, equipment, and systems. Harrison also works to customer-specific requirements.

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Passivation

Harrison Electropolishing, the Leading Electropolishing, Passivation, Oxygen Cleaning & Mechanical Polishing Company World Wide.

Electropolishing is an electrochemical process by which surface material is removed by anodic dissolution. Electropolishing removes surface material, beginning with the high points within the microscopic surface texture. By removing these points, the electropolishing process will improve the surface finish of a metal such as stainless steel, nickel, and Hastelloy, leaving a smoother and more reflective surface. Common parts and components electropolished include tanks, piping, fittings, rods, discs, large parts & surfaces, and more.