LEADS: What is Grade 317L Stainless Steel

Overview

317L (00Cr19Ni13Mo3, UNS S31726) alloy is a molybdenum-based austenitic stainless steel. With L behind the number, 317L is a low carbon grade. It has stronger resistance to chemical corrosion than conventional chromium-nickel austenitic stainless steels such as 304 alloy. In addition, 317L alloy has higher ductility, stress corrosion resistance, compressive strength and high temperature resistance than conventional stainless steel. It exhibits anti-sensitization properties during welding and heat treatment.

Features of Inox 317L

Type 317L features good seawater resistance and SCC resistance compared to 316L. It is used in chemical equipment such as chemical ships and chemical products such as reactor. In terms of chemical composition, 317L increases chromium, nickel, molybdenum by 2%, 1%, 1% respectively in comparison with 316, while these three elements are the main elements that determine stainless steel performance.

In terms of pitting resistance performance, 317 is higher than 304 and 316. The high molybdenum guarantees that 317L is more resistant to overall and local corrosion in most media, such as sulfuric acid, acid chlorine and phosphoric acid. However, 317L has poor corrosion resistance in strong oxidizing acids such as nitric acid. Basically, 317L has similar performance like 317. Due to lower carbon, 317L has better welding performance and intergranular corrosion resistance at high temperatures (427~816 °C).

Chemical Compositions

Mechanical Properties

317L Applications

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· 1) Oil and gas industry equipment;

· 2) Offshore platforms, heat exchangers, underwater equipment, firefighting equipment;

· 3) Chemical processing industry, utensils and pipeline industry;

· 4) Desalting, high pressure RO equipment and submarine pipelines;

· 5) Energy industry such as power plant desulfurization and denitration FGD system, industrial scrubbing system, absorption tower;

· 6) Mechanical parts that require high strength, corrosion resistant and anti-wear performance;

· 7) Others.