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Surface Treatment Procedures for Mild Steel




Q. Hello !

For your info, I'm a student doing research on corrosion of mild steel. I would like to know the "surface treatment" on mild steel. What is the procedure? What is the method used? From my understanding, We have cold-rolled, hot-rolled mild steel and etc. Can anyone explain, what is the surface treatment procedure used in both cold-rolled and hot-rolled mild steel.

p.s: Please reply to me as soon as possible. I need it urgently for my paper.

Abd Rahman Bin Alias
Master student. - UEP Subang Jaya, Selangor, Malaysia
2004


A. Hi, Abd.

Painting is the most common surface treatment for steel. There are, however, entire libraries of information about the surface treatment of steel, and the hundreds of different paints and paint pre-treatments, and the alternatives including galvanizing, electroplating, powder coating, nitriding, flame spraying, electrocoating, etc., etc.

What you might do for your project is take one type of steel item (bridges, automobile bodies, guardrails, freight cars, home appliances, transmission line towers, garbage cans, computer chassis) and write about the advantages and disadvantages of the alternative surface treatments for that one component. Good luck!

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey




Q. Currently the accepted practice of protecting mild steel structures in a tropical climate of India is by "HOT DIP GALVANIZING" in a molten Zinc bath. Is there any other less polluting but equally effective process? I have seen transmission towers in Germany look green in shade unlike Shining like silver in India. Solutions expected.

tushar parandekar
- Nashik, Maharashtra, India
September 28, 2010


A. Hi, Tushar.

When you say "less polluting", how much pollution do you think Hot Dip Galvanizing usually generates, and in what form? Is it air pollution, water pollution, or land pollution? If a suggested alternative produces less air pollution but more land pollution, or less land pollution but more water pollution, is that a good or bad answer? If it saves a brook trout but kills a beaver, is that an improvement? It is truly difficult and tricky to rate processes against each other as more polluting or less polluting. But if you visit the sites of galvanizing associations like galvanizeit.org you will see that they claim galvanizing to be green technology as zinc is an essential nutrient.

My own take on it is that galvanizing is far-&-away the best corrosion deterring surface treatment available for transmission towers, so any competing technology attempting to justify itself should have to include the environmental cost of more frequent maintenance and replacement, including the impact of manufacturing the replacement towers and the environmental degradation that occurs when installing and servicing them.

Galvanizing often lasts for 50-60 years and even more without maintenance -- do we believe that the alternative technology will last nearly as long, or are we just going for the lower price and rationalizing the decision with gobbledygook? But will we still be using those same transmission lines 50 years from now, or will they be extinct or relocated in a shorter time frame anyway? A very interesting but very difficult question :-)
Thanks.

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


A. Toxic air pollutants are emitted from galvanizing plants. Fine particles bypass the body's defense mechanisms with negative consequences for respiratory and cardiovascular systems. Hydrogen chloride emissions form corrosive hydrochloric acid on contact with body tissue, causing lung, skin and eye damage. ammonia [on eBay or Amazon] is also an irritant to the skin and eyes; chronic exposure may lead to irritation of the respiratory tract, asthma and lung fibrosis. Exposures to high levels of zinc have been associated with pulmonary inflammation and injury. Lead affects virtually every system in the body and is particularly harmful to young children.

Visit www.bredl.org for more information on pollution from steel galvanizing.

Look for this report: BREDL Factsheet: Pollution of the Air, Soil and Water by South Atlantic Galvanizing.

Beverly Kerr
- Graham, North Carolina, USA
June 25, 2011

Ed. note: Sorry, that's now a broken link; but readers can view it here on Archive.org. Patience please, archive.org must retrieve it from among billions of documents.

A. Hi, Beverly.

No one can justify lack of enforcement in any specific case, but your complaint seems to be about galvanizing in general.

I noticed that the BREDL site is certified green, powered by 100% wind energy. Aren't the wind turbines installed on its behalf built of hot dip galvanized steel? I pass them in Atlantic City and elsewhere, and they look like they are galvanized steel -- and I know of no other material of construction appropriate for wind turbines, bridges, transmission towers and other durable infrastructure. Please let me know if I got it wrong. Thanks!

opinion After years of endless pennywise & pound-foolish attacks on surface finishers and our quest for sustainability through proper corrosion-fighting treatments in a world that otherwise rusts away, society is reaping what has been sown: outdoor equipment that requires endless replacement. Instead of once and done, we are re-mining, re-transporting, re-smelting, re-transporting, re-rolling, re-transporting, re-fabricating, re-packaging, re-transporting, re-selling, re-assembling, re-installing, and re-landfilling every 3 years instead of the former 30+ years ... because, although we know exactly how to protect steel from corrosion properly, we rarely do it anymore -- we're just too weary from a lifetime of attacks from people with no interest in listening.

Sustainability is so yesterday. No one focuses on the ton of steel wasted every 3 years, we just constantly buy replacement patio sets and outdoor stuff, as regulators pressure metal finishers to eliminate the ounce of phosphate required to let stuff last 30+ years instead of 3 years, while there is absolutely zero pressure from anyone towards requiring that such items exhibit any durability :-(

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 30, 2011


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