321 stainless steel tubing

321 stainless steel tubing



Product Description

321 Stainless Steel Tubing

321 Stainless Steel Tubing

Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilised 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 425-850°C.

 

Grade 321 stainless steel tubing is the grade of choice for applications in the temperature range of up to about 900°C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.Grade 321H is a modification of 321 with a higher carbon content, to provide improved high temperature strength.

Applications of 321 stainless steel tubing:

Typical compositional ranges for grade 321 stainless steel tubing are given in table 1.

Table 1. Composition ranges for 321 grade stainless steel

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

Typical mechanical properties for grade 321 stainless steel tubing are given in table 2.

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