Stainless steel types 1.4401 and 1.4404 are also known as grades 316 and 316L respectively. Grade 316 is an austenitic grade second only to 304 in commercial importance. Stainless steel types 1.4401 and 1.4404 are also known as grades 316 and 3164L respectively. Grade 316 is an austenitic grade second only to 304 in commercial importance.
Stainless Steel Grades Explained
316 Stainless Steel
Stainless steel 316 contains an addition of molybdenum that gives it improved corrosion resistance. This is particularly apparent for pitting and crevice corrosion in chloride environments.
316L Stainless Steel
316L, the low carbon version of Stainless steel 316, is immune to grain boundary carbide precipitation (sensitisation). This makes it suited to use in heavy gauge (over about 6mm) welded components.
316Ti and 316H Stainless Steels
For elevated temperature applications the high carbon variant, 316H stainless steel and the stabilised grade 316Ti stainless steel should be employed.
The austenitic structure of Stainless steel 316 gives excellent toughness, even at cryogenic temperatures.
ASTM A240/A240M
Property data given in this document is typical for bar and section products covered by EN 10088-3:2005. ASTM, EN or other standards may cover all products sold. It is reasonable to expect specifications in these standards to be similar but not necessarily identical to those given in this datasheet.
Stainless steel grade 316Ti contains a small amount of titanium. Titanium content is typically only around 0.5%. The titanium atoms stabilise the structure of the 316 at temperatures over 800°C. This prevents carbide precipitation at the grain boundaries and protects the metal from corrosion. The main advantage of 316Ti is that it can be held at higher temperatures for a longer period without sensitisation (precipitation) occurring. 316Ti retains physical and mechanical properties similar to standard grades of 316.
Chemical Composition of Stainless steel 316
Table 1. Typical chemical composition for 316 stainless steel alloys
|
%
|
316
|
316L
|
316H
|
316Ti
|
|
C
|
0.0-0.07
|
0.0-0.03
|
0.04-0.08
|
0.0- 0.08
|
|
Mn
|
0.0-2.0
|
0-2.0
|
0.0-2.00
|
0.0-2.00
|
|
Si
|
0.0-1.0
|
0.0-1.00
|
0.0-1.00
|
0.0- 1.00
|
|
P
|
0.0-0.05
|
0.0-0.05
|
0-0.04
|
0.0-0.05
|
|
S
|
0.0-0.02
|
0.0-0.02
|
0.0-0.02
|
0.0-0.03
|
|
Cr
|
16.50-18.50
|
16.50-18.50
|
16.50-18.50
|
16.50- 18.50
|
|
Mo
|
2.00-2.50
|
2.00-2.50
|
2.00-2.50
|
2.00- 2.50
|
|
Ni
|
10.00-13.00
|
10.00-13.00
|
10.00-13.00
|
10.50- 14.00
|
|
Ti
|
-
|
-
|
-
|
0.40- 0.70
|
|
Fe
|
balance
|
balance
|
balance
|
balance
|
Properties of Stainless Steel 316
Mechanical Properties of Stainless Steel 316
Table 2. Typical mechanical properties for 316 stainless steel alloys
|
Grade
|
316 Bar and Section (up to 160 mm thick)
|
316 Sheet (up to 8 mm thick) |
316 Plate (8 - 75 mm thick) |
316L Bar and Section (up to 160 mm) |
316L Sheet (up to 8 mm thick)
|
316 L Plate (8 - 75 mm thick) |
316H Bar (up to 160 mm)
|
316Ti Bar (up to 160 mm) |
|
Tensile Strength (MPa)
|
500 - 700
|
530 - 680 |
520 - 670 |
500 - 700
|
530 - 680 |
520 - 670
|
490 - 690
|
500 - 700 |
|
Proof Stress (MPa)
|
200 Min
|
240 Min |
220 Min |
200 Min
|
240 Min |
220 Min
|
205 Min
|
200 Min |
|
Elongation A50 mm
|
40 Min %
|
40 Min %
|
45 Min %
|
40 Min %
|
40 Min %
|
45 Min %
|
35 %
|
40 Min % |
|
Hardness Brinell
|
215 Max HB
|
-
|
-
|
215 Max HB
|
-
|
-
|
-
|
215 Max HB |
Physical Properties of Stainless Steel 316
Table 3. Typical physical properties for 316 stainless steel alloys
|
Property
|
Value
|
|
Density
|
8.00 g/cm3
|
|
Melting Point
|
1400°C
|
|
Modulus of Elasticity
|
193 GPa
|
|
Electrical Resistivity
|
0.74 x 10-6 Ω.m
|
|
Thermal Conductivity
|
16.3 W/m.K
|
|
Thermal Expansion
|
15.9 x 10-6/K
|
Alloy Designations
Stainless steel 316 also corresponds to the following standard designations and specifications:
|
Euronorm
|
UNS
|
BS
|
En
|
Grade
|
|
1.4401
|
S31600
|
316S31
|
58H
|
316
|
|
1.4404
|
S31603
|
316S11
|
-
|
316L
|
|
-
|
S31609
|
316S51
|
-
|
316H
|
|
1.4571
|
-
|
320S31
|
-
|
316Ti
|
Corrosion Resistance of Stainless steel 316
Stainless steel 316 has excellent corrosion resistance when exposed to a range of corrosive environments and media. It is usually regarded as “marine grade” stainless steel but is not resistant to warm sea water. Warm chloride environments can cause pitting and crevice corrosion. Grade 316 is also subject to stress corrosion cracking above around 60°C.
Heat Resistance of Stainless steel 316
Stainless steel 316 has good resistance to oxidation in intermittent service to 870°C and in continuous service to 925°C. However, continuous use at 425-860°C is not recommended if corrosion resistance in water is required. In this instance 316L is recommended due to its resistance to carbide precipitation.
Where high strength is required at temperatures above 500°C, grade 316H is recommended.
Fabrication of Stainless steel 316
Fabrication of all stainless steels should be done only with tools dedicated to stainless steel materials. Tooling and work surfaces must be thoroughly cleaned before use. These precautions are necessary to avoid cross contamination of stainless steel by easily corroded metals that may discolour the surface of the fabricated product.
Cold Working of Stainless steel 316
Stainless steel 316 is readily brake or roll formed into a variety of parts. It is also suited to stamping, heading and drawing but post work annealing is recommended to relieve internal stresses.
Cold working will increase both strength and hardness of Stainless steel 316.
Hot Working of Stainless steel 316
All common hot working processes can be performed on Stainless steel 316. Hot working should be avoided below 927°C. The ideal temperature range for hot working is 1149-1260°C. Post-work annealing is recommended to ensure optimum corrosion resistance.
Heat Treatment of Stainless steel 316
Stainless steel 316 cannot be hardened by heat treatment.
Solution treatment or annealing can be done by rapid cooling after heating to 1010-1120°C.
Machinability
Stainless steel 316 has good machinability. Machining can be enhanced using the following rules:
- Cutting edges must be kept sharp. Dull edges cause excess work hardening.
- Cuts should be light but deep enough to prevent work hardening by riding on the surface of the material.
- Chip breakers should be employed to assist in ensuring swarf remains clear of the work
- Low thermal conductivity of austenitic alloys results in heat concentrating at the cutting edges. This means coolants and lubricants are necessary and must be used in large quantities.
Welding of Stainless steel 316
Fusion welding performance for 316 stainless steel is excellent both with and without fillers. Recommended filler rods and electrodes for Stainless steel 316 and 316L are the same as the base metal, 316 and 316L respectively. Heavy welded sections may require post-weld annealing. Grade 316Ti may be used as an alternative to Stainless steel 316 in heavy section welds.
Oxyacetylene welding has not been found to be successful for joining of Stainless steel 316.
316Ti
Another variation of 316 is available. This variation is 316Ti. Stainless steel 316Ti contains a small amount of titanium. Titanium content is typically only around 0.5%. The titanium atoms stabilise the structure of the 316 at temperatures over 800°C. This prevents carbide precipitation from the grain boundaries and protects the metal from corrosion. The main advantage of 316Ti is that it can be held at higher temperatures for a longer period without sensitisation (precipitation) occurring. 316Ti retains physical and mechanical properties similar to standard grades of 316.
Applications of Stainless steel 316
Initially developed for use in paper mills Stainless steel 316 is now typically used in:
- Food processing equipment
- Brewery, dairy, and pharmaceutical production equipment
- Chemical and petrochemical equipment
- Laboratory benches & equipment
- Coastal architectural panelling
- Coastal balustrading
- Boat fittings
- Chemical transportation containers
- Heat exchangers
- Mining screens
- Nuts and bolts
- Springs, nuts, bolts and screws
- Medical implants
- Sinks and splashbacks
- Saucepans
- Cutlery and flatware
- Sanitaryware and troughs
- Tubing
Supplied Forms
Stainless steel 316 is typically supplied by Aalco in a range of finishes in the following forms:
- Sheet
- Strip
- Tube
- Bar
- Pipe
- Plate
- Fittings & Flanges
DISCLAIMER
This Data is indicative only and must not be seen as a substitute for the full specification from which it is drawn. In particular, the mechanical property requirements vary widely with temper, product and product dimensions. The information is based on our present knowledge and is given in good faith. However, no liability will be accepted by the Company is respect of any action taken by any third party in reliance thereon.
As the products detailed may be used for a wide variety of purposes and as the Company has no control over their use; the Company specifically excludes all conditions or warranties expressed or implied by statute or otherwise as to dimensions, properties and/or fitness for any particular purpose.
Any advice given by the Company to any third party is given for that party’s assistance only and without liability on the part of the Company. Any contract between the Company and a customer will be subject to the company’s Conditions of Sale. The extent of the Company’s liabilities to any customer is clearly set out in those Conditions; a copy of which is available on request.
This information has been sourced, reviewed and adapted from materials provided by Aalco - Ferrous and Non-Ferrous Metals Stockist.
For more information on this source, please visit Aalco - Ferrous and Non-Ferrous Metals Stockist.