**1. Does salt water affect stainless steel?**
Yes, salt water can significantly affect stainless steel. While stainless steel is known for its corrosion resistance due to a protective chromium oxide layer, salt water is particularly aggressive. The chlorides in salt water can attack and break down this passive layer, leading to localized corrosion such as pitting and crevice corrosion. The higher the grade of stainless steel (e.g., 316 over 304), the better its resistance to salt water, but no stainless steel is completely immune, especially in warm, stagnant, or poorly aerated conditions.
**2. What is the enemy of stainless steel?**
The primary enemy of stainless steel is **chloride ions**. These are found in salt, salt water, and de-icing salts. Chlorides can penetrate the protective chromium oxide layer on the steel's surface, leading to pitting corrosion and crevice corrosion. Other enemies include mechanical abrasions that scratch the protective layer, prolonged exposure to high temperatures which can reduce corrosion resistance (sensitization), and contact with certain strong acids.
**3. What metal won't rust in saltwater?**
No common metal is truly 100% immune to all forms of degradation in saltwater over a very long period. However, several metals and alloys exhibit **extremely high resistance and are considered not to "rust"** (where rust refers specifically to the iron oxide corrosion of steel):
* **Titanium:** Highly resistant to pitting and crevice corrosion in saltwater, even at high temperatures.
* **Nickel alloys:** Alloys like Hastelloy, Inconel, and Monel are exceptionally resistant to chloride attack.
* **Super Duplex Stainless Steels:** Grades like 2507 offer very high resistance to chloride pitting.
* **Copper-Nickel alloys:** Alloys like 90/10 and 70/30 CuNi are specifically designed for excellent seawater resistance, resisting biofouling and corrosion.
**4. Does gold react with salt water?**
No, **pure gold is virtually unreactive with salt water**. It is one of the most inert metals, which is why it has been used for centuries in maritime and jewelry applications. It will not corrode, tarnish, or rust. However, it's important to note that gold used in jewelry is often an alloy (mixed with other metals like copper or silver). While the gold content itself won't react, these other alloying metals can potentially tarnish or corrode over very long periods in harsh salt water environments.
**5. What is TP316 material?**
**TP316** is a standard designation for a type of stainless steel tubing or pipe. The "T" stands for "Tube," and the "P" stands for "Pipe." The "316" refers to the specific ASTM grade of austenitic stainless steel. Therefore, TP316 is **316 stainless steel that has been manufactured to specific dimensional and mechanical standards for use as pipe or tubing**. It has a higher molybdenum content than 304 stainless steel, which gives it improved corrosion resistance, particularly against chlorides and in industrial and marine applications.
