STAINLESS STEEL TUBING 321

ss tubing 321 b

STAINLESS STEEL TUBING 321 manufacturer
Stainless Steel 321 Tubing specifications ASTM A/ASME SA213/A249/A269/A312/A358 CL. I to V ASTM A789/A790, Stainless Steel 321 Tubing Sizes (Seamless): 1/2" NB - 24" NB, Stainless Steel 321 Tubing Sizes (ERW): 1/2" NB - 24" NB , Stainless Steel 321 Tubing Sizes (EFW): 6" NB - 100" NB

Stainless Steel 321 Tubing Wall Thickness available:

Schedule 5S - Schedule XXS (heavier on request)

All about Stainless Steel 321 tubing:

Stainless Steel Type 321 is a standard austenitic 18/8 chromium nickel alloy with the addition of Titanium making it an excellent choice in elevated temperature environments. Stainless Steel Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilized by Titanium (321) or Niobium (347) additions. These grades are used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-8500C. Stainless steel Grade 321 is the grade of choice for applications in the temperature range of up to about 9000C, combining high strength, and resistance to scaling and phase stability with resistance to subsequent aqueous corrosion. Stainless steel Grade 347 is only occasionally used as parent plate material.

Like other austenitic grades, 321 and 347 have excellent forming and welding characteristics, are readily brake or roll formed and have outstanding welding characteristics. Post-weld annealing is not required. Stainless steel 321 if the requirement is simply for resistance to intergranular corrosion after welding. However 304L has lower hot strength than 321 and so is not the best choice if the requirement is resistance to an operating environment over about 5000C.

Table 1. Composition ranges for Stainless Steel 316/316L tubing

Grade C Mn Si P S Cr Mo Ni N Other
321 min.
max
-
0.08
2.00 0.75 0.045 0.030 17.0
19.0
- 9.0
12.0
0.10 Ti=5(C+N)
0.70
321H min.
max
0.04
0.10
2.00 0.75 0.045 0.030 17.0
19.0
- 9.0
12.0
- Ti=4(C+N)
0.70
347 min.
max
0.08 2.00 0.75 0.045 0.030 17.0
19.0
- 9.0
13.0
- Nb=10(C+N)
1.0


Table 2. Mechanical properties of 321 grade stainless steel

Grade Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50mm) min Hardness
Rockwell B (HR B) max Brinell (HB) max
321 515 205 40 95 217
321H 515 205 40 95 217
347 515 205 40 92 201
321H also has a requirement for a grain size of ASTM No 7 or coarser.

Table 3. Physical properties of 321 grade stainless steel in the annealed condition

Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (m/m/0C) Thermal Conductivity (W/m.K) Specific Heat 0-1000C (J/kg.K) Electrical Resistivity (n.m)
0-1000C 0-3150C 0-5380C at 1000C at 5000C
321 8027 193 16.6 17.2 18.6 16.1 22.2 500 720


Table 4. Grade specifications for 321 grade stainless steel

Grade UNS No Old British Euronorm Swedish SS Japanese JIS
BS En No Name
321 S32100 321S31 58B, 58C 1.4541 X6CrNiTi18-10 2337 SUS 321
321H S32109 321S51 - 1.4878 X10CrNiTi18-10 - SUS 321H
347 S34700 347S31 58G 1.4550 X6CrNiNb18-10 2338 SUS 347
These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.