Stainless Steel 316 | SS316 | SS316L

 Stainless Steel -
Grade 316, SUS316,UNS S31600 

Chemical Formula 

Fe, <0.03% C, 16-18.5% Cr, 10-14% Ni, 2-3% Mo, <2% Mn,
<1% Si, <0.045% P, <0.03% S 

Background 

SUS316
is the standard molybdenum-bearing grade, second in importance to SUS304
amongst the austenitic stainless steels. The molybdenum gives 316 better
overall corrosion resistant properties than SUS304, particularly higher
resistance to pitting and crevice corrosion in chloride environments. It has
excellent forming and welding characteristics. It is readily brake or roll
formed into a variety of parts for applications in the industrial,
architectural, and transportation fields. SUS316 also has outstanding welding
characteristics. Post-weld annealing is not required when welding thin
sections. 

SUS316L,
the low carbon version of SUS316 and is immune from sensitisation (grain
boundary carbide precipitation). Thus it is extensively used in heavy gauge
welded components (over about 6mm). SUS316H, with its higher carbon content has
application at elevated temperatures, as does stabilised grade SUS316Ti.  

 Corrosion Resistance 

Excellent in a range of atmospheric
environments and many corrosive media - generally more resistant than SUS304.
Subject to pitting and crevice corrosion in warm chloride environments, and to
stress corrosion cracking above about 60°C. Considered resistant to potable
water with up to about 1000mg/L chlorides at ambient temperatures, reducing to
about 500mg/L at 60°C. 

SUS316 is usually regarded as the standard
“marine grade stainless steel”, but it is not resistant to warm sea water. In
many marine environments SUS316 does exhibit surface corrosion, usually visible
as brown staining. This is particularly associated with crevices and rough
surface finish.  

 Dual Certification 

It is common for SS316 and SS316L to be stocked in "Dual Certified" form
- mainly in plate and pipe. These items have chemical and mechanical properties
complying with both SS316 and SS316L specifications. Such dual certified
product does not meet SS316H specification and may be unacceptable for high
temperature applications.