Stainless Steel Fastener Grades Explained
SS 202 is an economical grade for indoor use, SS 304 resists rust for general indoor and outdoor work, and SS 316 adds molybdenum for sea water and chemicals. In coastal Chennai, choose SS 316 for anything exposed to sea air.
SS 202
A lower-nickel stainless steel that costs less. It is fine indoors but can show surface rust outdoors and near the sea.
SS 304
The general-purpose stainless steel, also called A2. It resists rust in normal outdoor and indoor conditions and is used in kitchens, buildings, food equipment and signage.
SS 316
Also called A4, it contains molybdenum, which greatly improves resistance to chlorides. It is the right choice for marine, coastal, swimming pool, chemical and pharma applications.
Avoid mixing metals
Stainless bolts on galvanized or aluminium parts can cause galvanic corrosion in wet conditions. Use matching materials or insulating washers.
Galling
Stainless threads can seize when tightened fast. Use anti-seize compound on stainless bolts, especially in larger sizes.
