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Marine grade stainless

Marine grade stainless, or SAE 316 stainless steel, is a molybdenum-alloyed steel and is the second most common austenite stainless steel (after grade 304). It is the preferred steel for use in marine environments because of its greater resistance to pitting corrosion than other grades of steel. The fact that it is negligibly responsive to magnetic fields means that it can be used in applications where a non-magnetic metal is required. In addition to molybdenum, 316 also contains a number of other elements in varying concentrations (see table below). Like other grades of stainless steel, marine grade stainless steel is a relatively poor conductor of both heat and of electricity.

While 316 is not completely rust-proof, the alloy is more corrosion-resistant than other common stainless steels. Surgical steel is made from subtypes of 316 stainless steel.

Non-standard grades include 316H which has a "high" carbon content of greater than 0.04% giving it a high creep rupture strength at high temperatures, 316L(Hi)N which is an extra-high nitrogen grade (0.16-0.30%), 316Ti which is stabilized by titanium, 316Cb which is stabilized by niobium, 316L-SCQ which is a high-purity version of 316L, and 316LS which specially adapted for surgical implants.

Toltec Mounds Archeological State Park

Toltec Mounds Archeological State Park (3 LN 42), also known as Knapp Mounds, Toltec Mounds Site or Toltec Mounds, is an archaeological site from the Late Woodland period in Arkansas that protects an 18-mound complex with the tallest surviving prehistoric mounds in Arkansas. The site is on the banks of Mound Lake, an oxbow lake of the Arkansas River. It was occupied by its original inhabitants from 600 to 1050 CE. The site is designated as a National Historic Landmark.

Name

The identification of the site with the Toltec of Mexico was a 19th-century mistake. Mrs. Gilbert Knapp, owner of the land from 1857 to 1900, thought the Toltecs had built the mounds.

Investigations at the site by archaeologist Edward Palmer from the Smithsonian Institutions Bureau of American Ethnology in 1883 and by others since have proved that the indigenous ancestors of regional Native Americans had built these mounds and all other mounds within the present-day United States. They were part of mound building cultures that flourished from the Late Archaic period into the Protohistoric period. They built earthwork mounds for religious, political and ceremonial purposes, connecting them to their cosmology.