Mechanical Properties
|
200 Series |
300 Series |
0.2% proof stress (kg/mm2)
|
35.5 |
26.7 |
Tensile Strength (kg/mm2) |
77.2 |
59 |
Elongation |
50.0 |
55.6 |
GSN |
8-9 |
7.8 |
Hv |
208 |
157 |
Erchsen value |
12.5 |
12.9 |
Limited Drawing Limit |
2.0 |
2.3 to 2.5 |
Corrosion Properties
Considering that the components manufactured out of these sheets are used in normal atmospheric conditions chromium level 14.5% to 15.5% is quiet to resist pitting corrosion.
Experiments carried out showed the following result
- Kitchen utensils and cutleries retained their surface finish and luster similar to 304 Grade
- Laboratories scaled experiments carried out under different media revealed the following data:
Corrosion Rates of the Stainless Steels Fully Immersed in
3% Sodium Chloride
Stainless
Steel
|
Temperature |
Duration |
Corrosion
Rate |
Visual Observation |
°K |
°C |
(Hour) |
x 10^-2
mmpy |
J |
303±2 |
30±2 |
720 |
2.58 |
Localised
Attack |
S |
303±2 |
30±2 |
720 |
3.29 |
Localised
Attack |
J |
371±2 |
98±2 |
100 |
0.25 |
Material Remained Same |
S |
371±2 |
98±2 |
100 |
0.43 |
Material Remained Same |
Corrosion Rates of the Stainless Steels Fully Immersed in Organic Acid Mixture (0.5% Citric Acid+0.5% Tartaric Acid)
Stainless
Steel
|
Temperature |
Duration |
Corrosion
Rate |
Visual Observation |
°K |
°C |
(Hour) |
x10^-2
mmpy |
J |
303±2 |
30±2 |
720 |
0.44 |
Fungal growth |
S |
303±2 |
30±2 |
720 |
0.38 |
Fungal growth |
J |
371±2 |
98±2 |
100 |
0.34 |
Material Remained Same |
S |
371±2 |
98±2 |
100 |
0.17 |
Material Remained Same |
Dissolution Behaviour of the three stainless steels in 3% NaCl on total Immersion
SS |
Temp
°C |
Duration
(hours) |
Elements estimated by AAS (ppm) |
Fe |
Cr |
Cu |
Mn |
Ni |
Ti |
|
|
|
J |
30±2 |
720 |
0.177 |
0.011 |
0.003 |
0.508 |
- |
- |
S |
30±2 |
720 |
0.157 |
0.048 |
0.024 |
0.048 |
- |
- |
J |
98±2 |
100 |
0.057 |
0.007 |
0.015 |
0.829 |
- |
- |
S |
98±2 |
100 |
0.010 |
0.012 |
0.028 |
0.035 |
- |
- |
The above data suggest that the corrosion resistant as good as 304 Grade SS under normal atmospheric conditions
Formability
The blanks cut from the annealed sheets respond favorably to the commonly fabrication operations such as deep drawing ,spinning, welding ,bidding ,rib formation, embossing, electro deposition of metals like Copper and necking of cylindrical parts.
The quantified data on formability is given below: Limited Drawing Ration - 2
Percentage Stretch in Spinning - 30%
Erichsen Value - 12.5 |