Stainless Steel 316 or Stainless Steel 316L is an improved version of stainless steel 304, with the addition of molybdenum and a slightly higher nickel content. The resultant composition of stainless steel 316 gives the steel much increased corrosion resistance in many aggressive environments. The molybdenum makes the steel more resistant to pitting and crevice corrosion in chloride-contaminated media, sea water and acetic acid vapours. The lower rate of general corrosion in mildly corrosive environments gives the steel good atmospheric corrosion resistance in polluted marine atmospheres. stainless steel 316 offers higher strength and better creep resistance at higher temperatures than stainless steel 304.stainless steel 316 also possesses excellent mechanical and corrosion properties at sub-zero temperatures. When there is a danger of corrosion in the heat-affected zones of weldments, the low-carbon variety stainless steel 316L should be used. stainless steel 316 Ti, the titanium-stabilised version, is used for its resistance to sensitization during prolonged exposure in the 550oC-800oC temperature range.
Typical Applications
Because of its superior corrosion and oxidation resistance, good mechanical properties and fabricability, stainless steel 316 has applications in many sectors of industry. Some of these include: Tanks and storage vessels for corrosive liquids. Specialised process equipment in the chemical, food, paper, mining, pharmaceutical and petroleum industries. Architectural applications in highly corrosive environments.
Scrubbers for environmental control Duct works, stainless steel pipes, sewage water filters Heat exchanger stainless steel u tubes, ozone generators
Stainless Steel Flanges
Stainless Steel Pipe Fittings
Chemical Composition (ASTM A 240)
SX316 SX316L SX316Ti
C
0.08 max 0.03 max 0.08 max
Mn
2.0 max
P
0.045 max
S
0.030 max
Si
1.0 max
Cr
16.0 to 18.0
Ni
10.0 to 14.0
Mo
2.00 to 3.00
Ti
0.5 max 5X%C
Typical properties in the annealed condition The properties quoted in this publication are typical of mill products and unless indicated must not be regarded as guaranteed minimum values for specification purposes.
1. Mechanical properties at room temperature
Tensile Strength, MPa
Proof Strength, (Offset 0.2%), MPa
Elongation (Percent in L = 5.65 S0)
Hardness (Brinell)
Erichsen Cup Test Value mm
Endurance (fatigue) limit, MPA
SX316
TypicalMinimum
580515
310205
5540
165-
8 – 10-
260-
SX316L
TypicalMinimum
590485
310170
6040
170-
240-
260-
SX316Ti
TypicalMinimum
600515
320205
5040
165-
—
260-
2. Properties at elevated temperatures The values given refer to stainless steel 316 and stainless steel 316 Ti only as strength values for stainless steel 316Lfall rapidly above 425oC.
Short Time Elevated Temperature Tensile Strength
Temperature, °C
Strength, MPa
600
460
700
320
800
190
900
120
1000
70
Creep data Stress for a creep rate of 1% in 10 000 h
Temperature, °C
Stress, MPa
550
160
600
120
650
90
700
60
800
20
Recommended Maximum Service Temperature (Oxidising conditions)
Continuous Service 925oC Intermittent Service 870oC
3. Properties at Sub-Zero Temperatures ( Stainless Steel 316 )
Temperature
Proof Strength (0.2% Offset)
Tensile Strength
Impact Strength (Charpy V-Notch)
°C
MPa
MPa
J
-78
400
820
120
-161
460
1150
165
-196
580
1300
155
4. Corrosion Resistance
4.1 Aqueous For specific conditions, consult VRN technical staff. As a rough guide, the following examples are given for pure acid-water mixtures.
Temperature °C
Concentration, (-% by mass)
Sulphuric Acid
Nitric Acid
Phosphoric Acid
Formic Acid
20
10 20 40 60 80 100
0 1 2 2 1 0
0 0 0 0 0 1
0 0 0 0 1 2
0 0 0 1 1 0
80
10 20 40 60 80 100
2 2 2 2 2 2
0 0 0 1 1 2
0 0 2 2 1 1
0 2 2 2 2 0
Key: 0 = resistant – corrosion rate less than 100 >mm/year 1 = partly resistant – corrosion rate 100 m to 1000 >mm/year 2 = non resistant – corrosion rate more than 1000 mm/year
4.2 Atmospheric The performance of stainless steel 316 compared with other metals in various environments is shown in the following table. Corrosion rate is based on a 5 year exposure.
Environment
Rural
Marine
Marine Industrial
Corrosion Rate (µm/year)
SX 314Aluminium-3SMild Steel
0.00250.0255.8
0.00760.42434.0
0.0051068646.2
Note: For corrosion resistance of stainless steel 316 relative to other types, see the section in Comparative Data.
4.3.1 Annealing. Heat from 1 010oC to 1 120oC and cool rapidly in air or water. The best corrosion resistance is obtained when the final annealing temperature is above 1 070oC.
4.3.2 Stress relieving. Heat from 200 – 400oC and air cool.
4.3.3 Hot working Initial forging and pressing: 1150 – 1200oC Finishing temperature: above 900oC For upsetting operations, forgings should be finished between: 930 and 980oC All hot working operations should be followed by annealing.
Note: Soaking times to ensure uniformity of temperature are up to 12 times that required for the same thickness of mild steel.
Cold Working
Stainless Steel 316/316L, being extremely tough and ductile, can be readily fabricated by cold working. Typical operations include bending, forming, deep drawing and upsetting.
Typical product applications:
Condensers
Heat Exchangers
Stainless Steel Pipes
Pressure Vessels
Stainless Steel Valves
Stainless Steel Flanges
Typical industrial sectors:
Brewing
Chemical Industry
Dairy
Food processing
Marine equipment
Petrochemicals
Pharmaceuticals
All 316/316L at wilsonpipeline Pipe is certified to 316/316L which we stock at our warehouse in the CN with the capabilities to supply directly to countries across the world in all Stainless Steel Flanges, Stainless Steel Pipe Fittings, and Stainless Steel Pipes.
Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)
Comments