Stainless steel type 316 and type 304 are raw material grades for stainless steel. Stainless steel fasteners are sometimes referred to and ordered as their raw material grades (such as SS 316 and SS304) and sometimes referred to and ordered as their ASTM specification. The common ASTM specifications that cover stainless steel bolts are A193, A320 and F593. Type 316 stainless has a unique chemical composition which includes 16% chromium, 10% nickel and 2% molybdenum. Type 304 stainless has 18% chromium, 8% nickel and no molybdenum (this is where the “18-8” designation comes from). Stainless steel 316 is more resistant to chlorides than stainless steel 304, making it the preferred material for marine construction.
Sometimes, a type “SS316L” or type “SS304L” bolt will be specified in a particular application. The “L” at the end of these designations refers to the low carbon content of the steel. Stainless steel certified to 316L or 304L will have a maximum of 0.03% carbon, versus the 0.08% maximum that regular 316 and 304 can have. Low-carbon stainless steel bolts are used to avoid corrosion problems that are caused by welding, as the lower carbon content reduces the “sensitization effect” (the precipitation of chromium carbides at grain boundaries) caused by the high temperatures involved in welding. Since carbon is the principal hardening element in steel, low-carbon bolts have reduced hardness but are easier to weld.
The difference in carbon content does not affect the overall corrosion resistance of the steel, and low-carbon stainless steel bolts can be ordered to each of the A193, A320 and F593 specifications. When you order a low-carbon stainless steel bolt, just let us know about this requirement and our expert estimators will be sure to provide you with the correct material.
What are the marking mentioned on SS304, SS316 & alloy steel bolts ??
@Srikanth- Bolts made to 304 or 316 do not have any marking requirements. Individual manufacturers may choose to mark their bolts, but it is not required. Bolts made to the ASTM bolting standards, ASTM F593 or A193 have specific requirements, and those can be found on our website.
which stainless steel will give better life with h2 so4 concentration 6-10 %
304 L OR 316 L
ALSO COST EFFECT
@Bhagwan- typically 316 stainless is more corrosion resistant, however for specific applications like this, a metallurgist should be consulted.
can we use SS 304 seam plate for packing in SS 304L piping line.
Please reply asap.
@Abhishek- We can’t make specific material recommendation. You should consult the project engineer.
What are the magnetic properties of SS316L?
@Wojciech- Magnetic properties can vary a bit depending on what manufacturing processes have been performed on the steel. Some processes can increase or decrease magnetism as the grain structure gets altered. A metallurgist may be able to more clearly explain the specifics.
Can we use 304 bolts, nuts & Washers, near to sea area ? Also How long 304 bolts can withstand against Corrosion ?
@Antony- SS304 is commonly used in many close-to-sea applications, but you’d need to consult with an engineer to see if that is the best material for your specific application and to determine what the expected service life would be.