STAINLESS STEEL CORROSION DATA

Resistance of Stainless Steels to Chemical Media

 

1) Fully Resistant 0.002-inch Water Droplet
Click Here to Download Corrosion Data PDF
2) Satisfactorily resistant 0.010-inch
3) Fairly resistant 0.020-inch
4) Slightly resistant 0.040-inch/.050-inch
5) Not resistant 0.050-inch and over

 

The ability of stainless steels to resist corrosion is related to the chromium content, for chromium is the alloying element that endows stainless steels with their corrosion resistance. By combining with oxygen, chromium forms a thin but transparent chromium-oxide surface protective film. A steel must contain not less than 10% chromium to be considered stainless. As a general rule, the higher the alloy content, the more resistant it will be to corrosion because of the passive oxide film. Because of the important role of this film, care must be observed in manufacturing or in the operation and use of stainless steel components to avoid destroying or disturbing its passivity. Normally the destruction or disturbance of the protective film can be reformed or healed in the presence of oxygen to again provide maximum protection.

The stable protective nature in atmospheric or mild aqueous environments can be enhanced by higher chromium, nickel, molybdenum and other alloying elements. Chromium improves film stability; molybdenum and chloride penetration; and nickel acid environments. For example, Type 316 contains about the same amount of chromium as Type 304, more nickel, and 2 to 3% molybdenum. Type 316 is more resistant to corrosion that Type 304, especially chloride's pitting attack, and it is widely used in chemical processing because of its increased resistance to aggressive agents.

In rural atmospheres, virtually all stainless steels will give completely satisfactory service in terms of atmospheric corrosion resistance. In industrial environments, the choice to which stainless steel to use is fairly broad, except many users tend to prefer the 300 Series stainless steels, such as Type 304, because of their all-around good corrosion performance and ease of fabrication. While there is little concern about the sulphur content of the atmosphere, which has been known to accelerate corrosion in other metals, the primary concern with stainless steel is the presence of chlorides. In industrial area, dust and flying ash containing chlorides accumulate on flat surfaces. And if there is insufficient rainfall to wash away the accumulation, the possibility of some staining or pitting attack on the stainless steels with lower alloy content must be considered. Higher alloy grades such as Type 316 may be advisable.

As the chloride content of the industrial environment increases, such as near chemical plants producing chlorine or hydrochloric acid, corrosive stainless steels exposed in New York City for periods of up to 26 years were essentially unaffected. The same materials exposed to a chemical environment near Niagara Falls were attacked to varying degrees in much shorter periods. In such areas, the selection of materials is more critical, but the choice can still be made from among the range of stainless steel alloys.

Marine environments are also high in chlorides and are notoriously aggressive to metals, but stainless steels are preferred for construction in many coastal applications. A thin rust film may develop on the surface of those stainless steel types, but in most instances this is more a visual impairment than a functional failure from corrosion. Type 304 is used for coastal atmospheres and does very nicely especially where the metal is exposed to regular rainfall or is washed occasionally. Where staining is objectionable as with architectural applications, Type 316 is the preferred choice which has greater resistance to staining. Conditions below the surface of the ground can be fair more aggressive than those in the atmosphere, because materials are frequently submerged for long periods in soils containing water, salts, or chemicals, all of which increase the potential corrosivity of the environment. These soils are subject to a complex set of conditions that may vary from time to time, depending upon the weather and other circumstances.

Nevertheless, stainless steels are often preferred for sub-surface environments. To provide more complete data on the performance of stainless steels in underground applications, including data on many different soil conditions, the Committee of Stainless Steel Producers initiated an extended test program in cooperation with the National Bureau of Standards. The results of this program, which continue, are available from Washington Steel Corporation.

Laboratory Corrosion Resistance Tables The data contained in the following tables, while indicative of what can be expected in service, cannot be considered an absolute reference in predicting service results. Whenever possible, samples should be exposed to actual operating conditions before drawing any conclusions.

For comparative purposes, these tables include data on Type 304 and 316. If there is any question as to the suitability in a specific corrosive environment, the question should be referred to our customer service. The approximate corrosion resistance is shown here.

Click Here to Download Corrosion Data PDF

 

  • Stainless Armor Series

    Stainless Armor Series

    True
    16 Gauge
    Stainless

    Heavy duty 16 gauge type 304 SS industrial grade stainless self-rimming and under-mount fixtures

  • Made in the U.S.A

    Stainless Steel Products Made in USA

    USA MILL SPEC
    Certified

    Secure your stainless steel sink specifications with Just Manufacturing “Made in USA” plumbing products produced from USA Mill Certified stainless steel.

  • Building Information Modeling

    Building Information Modeling for Just products

    Just Manufacturing Product Files

    Just Manufacturing is now your source for Building Information Modeling

  • Sensor Faucets

    Faucets, Drains, Bubblers - Just Manufacturing

    Just Enviro
    Series Sensor Faucets

    Comprehensive offering of deck-mount, backsplash, goose-neck, AC & DC powered commercial sensor faucets. Lavatory offering includes deck-mount single or two-hole option installation.

  • Environment

    Just Manufacturing’s Commitment to GREEN Awareness

    Just Manufacturing’s Commitment to GREEN Awareness

    In-plant production as well as inbound raw materials and packaging are factored in to our GREEN planning recycling efforts.

  • Lead Free

    Certified Lead-Free Products

    Reduction of Lead in Drinking Water Act

    Just Manufacturing offers a comprehensive line of commercial Lead-Free products that comply with the U.S. Safe Drinking Water Act.

  • Integra Flow

    Integra Flow System to Reduce Flooding Incidents

    The Integra Flow System

    Secure your specifications with the Just Integra Flow Overflow

  • Sinks Express

    Just In Time Inventory Management

    95% off-the-shelf fill rate

    95%+ off-the-shelf delivery; Just Manufacturing is your partner for Just-in-Time inventory management.

  • Family Owned
live chat service provider