How an Acid Inhibitor Protects Steel

Here’s a visual (and dramatic) demonstration in our labs of how a hot acid bath will eat away at the steel your company works hard to produce. Use of one of our acid inhibitors (in this case, Activol® 1803) in the pickling process significantly reduces your surface pitting and metal loss to the acid.

Why Pickling Processes Require an Acid Inhibitor

The video below graphically demonstrates what happens to steel in hot HCl, once the scale is removed. (Remember that 90% of the scale is removed early on in the pickling process; the last tank or maybe tank and a half is necessary to remove the edge scale, which is the most difficult scale to remove.)

Therefore, for most of the process, the strip is actually descaled and is being dissolved in the acid in the form of iron chloride. The result is that the strip becomes overpickled, your yield is degraded, and the HCl is being consumed needlessly, thereby increasing your operating costs.

Learn More About Acid Inhibitors

In this video, the metal used is descaled, grade 1011 steel in a bath of hydrochloric acid. The acid is eating away at the steel at a remarkable rate until the Activol® 1803 is added to protect the steel from the pickling process. Learn more about acid inhibitors (in general) and our acid inhibitors (in particular). Looking for more corrosion inhibitors? Try our Steelgard products!

Find the Perfect Acid Inhibitor

If you have additional questions, or need assistance to determine which of our acid inhibitor products will work best for your particular process,  give us a call: 215-324-4000. We also offer special custom formulations if your needs are unique. We have over 79 years of experience and can make your manufacturing process run a little smoother.

Acid Inhibitor Delivery System Detailed

Activol acid inhibitor in use in a product line of one of our clients.One of our clients has set up an Activol® acid inhibitor system to meet their daily needs. Mike Estes of has provided the following photo of the set-up they use to consistently process the Activol® product into their on-site acid farm.

The set-up involves the use of a plastic drum, marked with the correct level of Activol® product on the outside of the drum. The bulk tank is piped into the drum and it uses a gravity feed.

Once the Activol® reaches the correct level, a pump is turned on and the inhibitor is pumped into the acid line where it remains until the acid truck is emptied, washing the inhibitor into the acid storage tank during unloading.

This system offers a simple and accurate solution. Thanks, Mike, for sharing the photo and your system!

(Note: If you would like to share your own experiences with Harry Miller Corp Products, please contact us. We would love to feature you!)

Acid Inhibitors-Rinse Aids-Acid Additives

abstract metal squares image for acid inhibitors page

To provide high quality, oxide-free steel for finishing requires the use of an acid inhibitor (also called an acid additive) in the pickling operation. An effective acid inhibitor minimizes acid attack on the base metal once the scale has been removed, protecting the surface and optimizing acid utilization.

Activol® acid inhibitors have been proven superior to other brands in field trials, whether hydrochloric or sulfuric pickling; continuous, push-pull lines or batch.

Total benefits of Activol® acid inhibitors may equal 8 times the cost of the acid additive!

Activol® Acid Inhibitors


Activol® 1803 is the premiere acid additive for hydrochloric acid pickling baths in steel mills. It fulfills all the requirements of a good pickling inhibitor: descaling, high efficiency, durability, rinsability, reduced acid consumption, fume reduction ad uniformly pickled surfaces.



  • Provides a high degree of restraining action to the attack of hydrochloric acid on base steel. Inhibition values typically increase from 92% as inhibitor concentration is raised from 1/16% to 1/2%.
  • Does not retard the descaling rate of oxides on steel surfaces.
  • Wetting properties allow a uniformly pickled surface, free from smut or ingrained scale.
  • Creates uniformly pickled metal surfaces with a shiny surface and minimal edge corrosion.
  • Reduced hydrogen evolution at the solution/steel interface reduces hydrogen embrittlment.
  • Pleasant odor facilities manual addition.
  • Stable in pickling solutions for extended time periods at elevated temperatures without losing inhibiting action.


Activol® is used at 1/8% to 1/4% based on the amount of raw acid in the pickling bath. View the Activol® 1803 delivery system setup sent in by one of our clients.

Other Benefits

Other benefits that come with the introduction of Activol® 1803 as an acid additive:

  • Uniform, brighter pickled surface, free of smut or ingrained scale
  • Easily rinsed
  • Prevents hydrogen embrittlement
  • Reduces acid fumes
  • Reduced overall production cost

Customer Experience

A major producer of high quality steel sheet was looking for increased efficiency in its pickling operation. The company was already using an acid inhibitor and believed that better inhibitor technology could decrease acid consumption, lower total costs and improve product quality.

The introduction of Activol® 1803 resulted in savings in Acid consumption 194,000 gallons per year/$70,000 per year.

Learn more about Activol by reading our Pickling FAQ page.

Hamico® Rinse Aids


Hamico® 8906-WT prevents carryover products from depositing on the immersed steel surface. It also protects the rinsed surface after it exits the rinse section and before it dries. It ensures good wetting on the metal surface and is low-foaming, minimizing disposal and water treatment issues.

Hamico® 8906-WT eliminates brown or reddish line stop stains that can form on steel as it exits from a continuous pickling line. It also prevents iron hydroxide slimes from forming in rinse tanks as a result of acid bath carryover.


  • Protects steel from flash rust after rinse
  • Eliminates rinse tub gels and slimes
  • Good wetting for better rinsing of chlorides and sulfates
  • Non-toxic
  • Low-foaming for easier disposal


Add Hamico® 8906-WT directly to the rinse tank water. Pre-mixing is not necessary. A typical initial charge to a tank is 1/8 to 1/4% by volume. Subsequent additions depend on the rate of rinse tank dilution. Meter it into the system at a 1/8 to 1/4% concentration with incoming rinse water.

Other Rinse Aids

Boilers and Industrial Equipment Cleaning

When you are cleaning boilers, heat exchangers, paper mill digesters, and other high-investment pieces of equipment in your facility, you want them to be protected from corrosion during the process. We offer Potentol® 2803 and Potentol® 2804.

Process & Equipment Information

Acid may be pre-inhibited by the supplier, added upon delivery, or metered in to the pickle line. Consult your HMC technical representative to discuss the best method for your operation, or to recommend accurate and reliable product metering equipment for your pickle line.