Stainless steel 304 and 316L comparison

NORIKA stainless steel 304 and 316L pipes are durable, corrosion resistant and heat resistant.

The quality is controlled strictly according to the standard AS/NZS4020. The advantage of 316L stainless steel lies in its corrosion resistance, such as chlorides and chlorination solutions (marine and chemical fields). This makes 316L stainless steel products particularly suitable for (marine and chemical fields). However, 304 stainless steel is sufficient to cope with the ordinary use environment, so that the maximum performance-to-price ratio can be obtained. Various uses of stainless steel pipes include household and construction, water and sewerage systems, industrial water pipes and water pipes, as well as the construction industry. For the convenience of customers, on the NORIKA® stainless steel pipe, both ends are marked with the insertion depth of the clamping pipe fittings. There is a cut half length mark in the middle of the 5.8 m long pipe. At the same time, in order to reduce the workload of the packers and respond to the needs of customers, NORIKA® developed a 2.9m stainless steel pipe.

Stainless Steel 304 vs 316L

Stainless steel pipes are comprised of a steel alloy and a small percentage of chromium — the addition of chromium adds to the material’s corrosion resistance. Because stainless steel is also low-maintenance, oxidation resistant, and doesn’t affect other metals it comes in contact with, it is frequently used in a large array of applications, especially in piping and tubing manufacturing. Stainless steel SS304 and SS316L is an American Iron and Steel Institute (AISI) basic grades, the only practical difference between SS304 and SS316L is its carbon content in which the L meant that it has lower carbon content. The carbon ranges are 0.08% maximum for stainless steel SS304 and 0.030% maximum for the stainless steel SS316L types.

Effect of carbon on corrosion resistance

The lower carbon stainless steel variants (SS316L) will overcome the risk of intercrystalline corrosion (weld decay), which was identified as a drawback in the early days of the application of these steels. This can result if the steel is held in a temperature range 450 to 850°C for periods of several minutes, depending on the temperature and subsequently exposed to aggressive corrosive environments. Corrosion then takes place; if the carbon level is below 0.030% then this intercrystalline corrosion will not occur when exposed to these temperatures.

Effect of carbon level on weldability

There is an assumption that the stainless steel with low carbon types (SS316L) are much easier to weld than the standard carbon types. There does not seem to be a coherent reason for this and the differences are probably associated with the lower strength of the low carbon type. The low carbon type may be easier to shape and form, which in turn may also affect the levels of residual stress left the steel after its forming and fitting up for welding. This may result in the standard carbon types (SS304) needing more force to hold them in position once placed for welding, it has a tendency to spring-back if not properly held in place. The welding consumables for both types are based on a low carbon composition, to avoid intercrystalline corrosion risk in the solidified weld nugget or from the diffusion of carbon into the surrounding metal.

In conclusion

SS304 and SS316L are both versatile and commonly used as they are structurally sound, great for construction jobs and holds up well in most conditions. Whereas SS316L has a superior corrosion resistance when exposed to different types of chemical corrodents such as sea water, brine solutions and the like making it more durable in harsh and corrosive environments and will hold up well in extreme conditions. While SS304 are commonly used in corrosion resistant electrical enclosures, exhaust manifolds, storage tanks pressure vessels and piping. If you have an application with very powerful corrosives or relies on chlorides, then paying a premium for grade 316L stainless steel is definitely worth it. In such applications, 316L stainless will last many times longer than grade 304 stainless would—which can mean many extra years of useful life. However, for applications using milder acids or where salt exposure isn’t a concern, grade 304 can work just as well.