Grade 316 / 316L Technical Data

Summary

Grade 316 is an improved version of CS 304, with the addition of molybdenum and a slightly higher nickel content. The resultant composition of CS 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.
CS 316 offers higher strength and better creep resistance at higher temperatures than CS 304. CS 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 CS 316L should be used. CS 316 Ti, the titanium-stabilised version, is used for its resistance to sensitization during prolonged exposure in the 550^oC-800^oC temperature range.

Typical Applications

Because of its superior corrosion and oxidation resistance, good mechanical properties and fabricability, CS 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.

Chemical Composition (ASTM A 240)

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

2. Properties at elevated temperatures
The values given refer to CS 316 and CS 316 Ti only as strength values for CS 316L fall rapidly above 425^oC.

Short Time Elevated Temperature Tensile Strength

Creep data
Stress for a creep rate of 1% in 10 000 h

Recommended Maximum Service Temperature
(Oxidising conditions)

Continuous Service 925^oC
Intermittent Service 870^oC

3. Properties at Sub-Zero Temperatures
( CS 316 )

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.

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 CS 316 compared with other metals in various environments is shown in the
following table. Corrosion rate is based on a 5 year exposure.

Note: For corrosion resistance of CS 316 relative to other types, see the section in Comparative Data.

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4.3.1 Annealing. Heat from 1 010^oC to 1 120^oC and cool rapidly in air or water. The best corrosion
resistance is obtained when the final annealing temperature is above 1 070^oC.

4.3.2 Stress relieving. Heat from 200 - 400^oC and air cool.

4.3.3 Hot working
Initial forging and pressing: 1150 - 1200^oC
Finishing temperature: above 900^oC
For upsetting operations, forgings
should be finished between: 930 and 980^oC
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

CS 316 / 316L, being extremely tough and ductile, can be readily fabricated by cold working. Typical operations include bending, forming, deep drawing and upsetting.