321 austenitic stainless steel has good corrosion resistance in the atmosphere, and is widely used in petrochemical, electric power, bridge and automobile industries.
But the stainless steel "rust" is not absolute, because of the special service environment, stainless steel will also occur corrosion.
Medium concentration, pH value, temperature and other factors will have a greater impact on the corrosion resistance of stainless steel.
For example, in the range of 450~850℃ sensitization temperature long-term use, stainless steel will occur intergranular corrosion.
The mechanism is that C combines with Cr at grain boundary to form Cr23C6 and precipitates out, which reduces Cr content at grain boundary, which is the so-called "poor chromium".
The Cr element is one of the main elements to inhibit the intergranular corrosion. When the Cr content at the grain boundary is less than 12%, the probability of intergranular corrosion will increase.
Equivalent Grades
| Grade |
Euronorm |
China GB |
Japanese JIS |
Germany |
| No. |
| 321 |
1.4541 |
0Cr18Ni10Ti |
SUS321 |
X10CrNiTi189 |
Standard Specification
| Thickness |
0.1mm-12mm |
| Width |
1000mm, 1219mm, 1500mm, 1800mm, 2000mm, 2500mm, 3000mm, 3500mm, etc |
| Length |
Customized |
| Surface |
2B, 2D, BA, NO.1, NO.4, NO.8, 8K, mirror, checkered, embossed, hair line, sand blast, Brush, etching, etc |
| Finish |
Hot rolled coil (HR), Cold rolled coil (CR), 2B, 2D, BA NO(8), SATIN (Met with Plastic Coated) |
| Form |
Round hole, square hole, diamond hole, hexagonal hole, waist round hole, rectangular hole, triangular hole, pattern hole, non-standard hole, large and small holes, gradient hole, cross hole, plum blossom hole |
Composition content
| Grade |
C |
Mn |
Si |
P |
S |
Cr |
Mo |
Ni |
N |
| 321 |
Min.
Max. |
0.08 |
2 |
0.75 |
0.045 |
0.03 |
17.00-19.00 |
/ |
9.00-12.00 |
0.1 |
Alloys 321 and 347 have similar resistance to general corrosion as the unstable Ni-Cr 304.
Prolonged heating in the temperature range of the chromium carbide degree may affect the corrosion resistance of alloys 321 and 347 in harsh corrosive media.
The corrosion resistance of the two alloys is similar in most environments;
However, the corrosion resistance of the annealed alloy 321 in the strong oxidizing environment is slightly lower than that of the annealed alloy 347.
Alloy 347 is therefore superior in water and other low temperature environments.
When exposed to the temperature range from 800°F to 1500°F (427°C to 816°C), the overall corrosion resistance of alloy 321 is much worse than that of alloy 347.
Alloy 347 is primarily used for high temperature applications where strong resistance to sensitization is required to prevent intergranular corrosion at lower temperatures.
Characteristic machining technology
2B -- Silver white with better gloss and flatness than a 2D surface.
Processing technology: hot rolling + annealing shot peening pickling + cold rolling + annealing pickling + quenching and tempering rolling.
Ba - Excellent surface gloss, high reflectivity, like a mirror surface.
Processing technology: hot rolling + annealing shot peening pickling + cold rolling + annealing pickling + surface polishing + quenching and tempering rolling.
No.3 -- Good gloss, coarse grain surface.
Processing technology: polishing and tempering rolling for 2D or 2B with 100~120 abrasive materials (JIS R6002).
No.4 -- Good gloss, fine lines on the surface.
Processing process: polishing and tempering rolling for 2D or 2B with 150~180 abrasive materials (JIS R6002).
HL -- Silver grey with hair streaks.
Processing technology: 2D products or 2B products with appropriate granularity of abrasive materials for polishing the surface is a continuous abrasive grain.
MIRRO -- Specular.
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