Stainless Steel Applications

Penn Stainless Products, Inc 190 Kelly Road

Quakertown, Pa 18951800-222-6144 Fax: 215-536-3255

www.pennstainless.com & www.dynamicwaterjet.com & www.pipeandtubes.com

Overview

The Costs of Corrosion

Corrosion Happens…..So What!?

Well… things fall apart.

Reducing the Impact of Corrosion

“Approximately one-third of the costs could be reduced by broader application of corrosion resistant materials and the application of best corrosion related practices (Battle Study).”

“Virtually all premature corrosion failures occur for reasons which were already well known and these failures can be prevented (Mars Fontana).”

Progreso Pier Mexico: Applying Better Practices

• The 6,980 foot pier was constructed from 1937 – 1941 using 304 stainless rebar

• In 1998, Ramboll consulting engineers inspected the pier and reported minimal structural fatigue

What is Stainless Steel? What makes it “Stainless”?

• Stainless steel must have at least 10% chromium in its content to be classified as a stainless steel.

• Nickel, Molybdenum and other elements are often combined with chromium to improve the corrosion resistance, strength, or heat resistance of the material.

• There are over 50 different “flavors” of stainless steels that can be selected for different applications and processes.

Let’s take a step back. What Makes Stainless Steel work and how do we make stainless steel work better on our projects?

What Makes Stainless Work?

Chromium Oxide Layer

Oxide Layer Damaged

Chromium Oxide Layer Repaired

For the Chromium oxide to repair—oxygen must be present!

This Chemistry “stuff” matters…a lot!

How to Preserve the Chromium Oxide Layer

Summary of Best Practices for Handling Stainless Materials

1. Keep your stainless and carbon steel fabrication areas separate.

2. Separate stainless and carbon inventories. 3. Use stainless steel processing and handling equipment

when possible.4. Use Work table bearers; non- stainless lifting 'dogs' and

chain marks can introduce iron contamination. Non-metallic contact materials and vacuum lifting equipment should be used.

5. Packing & Shipping – Tarp your stainless steel fabrications.

6. Communicate with your partners about the proper treatment of stainless steel

Now you know what to do. Does everyone else?

Do not allow grinding to take place near stainless fabrication.

NYC Far Rockaway

• Carbon Contamination from grinding

• Deicing salt

Part 2: Types of Corrosion

• Uniform Corrosion: Also known as general corrosion, is characterized by an even, general wasting away of metal from the corroding surface.

Was the correct material selected?

Pitting Corrosion

• Pitting Corrosion: described as an extreme case of localized attack which produces cavities or pits in the material.

• Was the stainless steel maintained correctly?

• Stainless Steels are susceptible to pitting corrosion.

• Avoid Chlorides.

316/L 7” SQ x ½ Wall Structurals, Polished with Minor Pitting Corrosion

Pitting / Surface Corrosion

• Staining from iron contamination

• Salt and chlorides present

Surface after passivation

Crevice Corrosion

• Crevice Corrosion: a particular form of localized corrosion which occurs in crevices formed between two surfaces.

• When possible, avoid tight corners or crevices in design

• Avoid spot welding, use continued welds when possible

• Use non absorbent gaskets, avoid chlorides

It’s All About the Surface Finish

Rougher surface is harder to clean, harder to remove contamination and more prone to corrosion

Accelerated salt spray test

Source: British Stainless Steel Association

Polished 304/L Stainless Steel I Beams (Cornell University)

Dairy Processing Facility: polished surface improves appearance while enhancing corrosion

Deeper Collaborations

• We need deeper, more open collaborations & dialog in order to “discover” and solve problems

• Work closely with suppliers and customers to solve technical challenges, save costs and offer better products and services.

• Our aim is to be this type of collaborative partner.