In many marine projects in Latin America, clients recommend the use of marine sheet piles. Many clients request ASTM A690 steel sheet piles. We have a wide selection of this steel grade. What is A690 steel? You can find its mechanical properties and chemical composition below.

For half a century, a wide variety of steel grades have become available. The U.S. Army Corps of Engineers does not recommend the use of A690 steel in any of its projects. Steel corrosion is associated with neutral water and oxygen, with the reaction equation being Fe + H₂O + 1/2O₂ → Fe(OH)₂. The resulting Fe(OH)₂ further reacts with oxygen, combining with or dissociating from H₂O to form "rust," which is composed of FeOOH, Fe₃O₄, and an amorphous substance. They recommend the use of lightweight steel in low-tide and splash zones, coated with paint.

Please note that while A690 is a high-modulus steel sheet pile, its strength is moderate. The reaction that turns steel to "rust" occurs electrochemically. If your building is not submerged in water or a marine environment, over 50% of materials can replace ASTM A690 and ASTM A572. If your building is submerged in seawater and your sheet piles are submerged in seawater, ASTM A690's claims are not advantageous.

If you are unfamiliar with corrosion calculations, you may want to read some articles on rust and corrosion. For various reasons, countless extremely fine anodes (positive electrodes) and cathodes (negative electrodes) exist on the surface of steel, forming localized batteries. Simply using A690 steel does not necessarily extend the service life of steel sheet piles. Understanding this allows engineers to find other solutions, saving clients significant time and money. If you work in a marine environment, you should be aware that A690 steel does not necessarily extend the service life of steel sheet piles, nor is it the best choice. Furthermore, it is expensive and has limited availability.

ASTM states that A690's corrosion resistance outperforms A36 and A328 only in the seawater splash zone. Iron dissolves at the localized anode, and oxygen reduction occurs at the cathode, allowing the corrosion reaction to continue.

A690, regardless of copper content, inherently offers significantly better atmospheric corrosion resistance than ordinary carbon steel. This steel, particularly in the "splash zone," demonstrates the strengths and weaknesses of ordinary carbon steel (specifications A36/A36M and A328/A328M). In the splash zone, it is exposed to wind, rain, sunlight, or both, and undergoes a drying process.

The U.S. Army Corps of Engineers uses EM-CR-1.6: A690 Statement for Marine Sheet Piling.

Unless a structure is exposed to saltwater (seawater) or alkaline water, uses high-yield-strength steel, or is exposed to the splash zone and atmosphere, A328 covered sheet piles should be used.