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Stainless Steel · Pipes · ASTM A312 / ASME SA312 TP347

SS 347 Stainless Steel Pipes

In short: SS 347 pipe to ASTM A312 TP347 is niobium-stabilised stainless pipe for welded lines in the sensitising range, common in refinery, chemical and aerospace ducting.

S34700
UNS number
7.96
density, g/cm³
3.1 / 3.2
EN 10204 certificates
5
SS 347 product forms
Quote SS 347 pipes →Sizes and weights
SS 347 pipe weight by sizeCalculated at 7.96 g/cm³: ½" 1.29 kg/m; ¾" 1.71 kg/m; 1" 2.54 kg/m; 1¼" 3.44 kg/m; 1½" 4.10 kg/m; 2" 5.52 kg/m; 2½" 8.76 kg/m; 3" 11.45 kg/m; 4" 16.30 kg/m; 6" 28.66 kg/m; 8" 43.14 kg/m; 10" 61.15 kg/m; 12" 74.91 kg/m. SS 347 pipe weight by size7.96 g/cm³ ½": 1.29 kg/m½"¾": 1.71 kg/m¾"1": 2.54 kg/m1"1¼": 3.44 kg/m1¼"1½": 4.10 kg/m1½"2": 5.52 kg/m2"2½": 8.76 kg/m2½"3": 11.45 kg/m3"4": 16.30 kg/m4"6": 28.66 kg/m6"8": 43.14 kg/m8"10": 61.15 kg/m10"12": 74.91 kg/m12" 74.9 NPS, Sch 40S · kg/m
Calculated values for estimating; actual weights vary within tolerances.

Why this combination

Why SS 347 in pipes

Niobium-stabilised: Nb ≥ 10×CExcellent resistance to intergranular corrosion after weldingGood creep and stress-rupture strengthStandard filler for stabilised grades (ER347)

Niobium survives welding better than titanium, so SS 347 welded pipe keeps its stabilisation through the joint, which is why it is chosen for heavily welded hot systems.

For creep-governed pressure piping, specify SS 347H.

Specification

How to specify SS 347 pipes

NPS ⅛" to 48" and larger (DN 6 – DN 1200+), schedules 5S to XXS, single random, double random and cut lengths

SS 347 pipe cross-section, NPS 6 Sch 40S Engineering drawing showing outside diameter 168.28 mm and wall thickness 7.11 mm (ASTM A312 TP347). Wall thickness is exaggerated for clarity. OD 168.28 mm WT 7.11 mm NPS 6SCH 40S ASTM A312 TP347
SS 347 pipes: ASTM A312 / ASME SA312 TP347 (seamless & welded)
Specification
ASTM A312 / ASME SA312 TP347 (seamless & welded); A358 EFW
UNS
S34700
EN / W.Nr.
1.4550
Grade marking
TP347

Sizes and weights

SS 347 pipes sizes, weighed at 7.96 g/cm³

Other sizes on request. For general pipes information, such as manufacturing routes and end finishes, see the pipes guide.

SS 347 pipe: wall (mm) / weight (kg/m) at 7.96 g/cm³, ASME B36.19M
NPSOD mmSch 5SSch 10SSch 40SSch 80S
½"21.341.65 / 0.812.11 / 1.012.77 / 1.293.73 / 1.64
¾"26.671.65 / 1.032.11 / 1.302.87 / 1.713.91 / 2.23
1"33.401.65 / 1.312.77 / 2.123.38 / 2.544.55 / 3.28
1¼"42.161.65 / 1.672.77 / 2.733.56 / 3.444.85 / 4.53
1½"48.261.65 / 1.922.77 / 3.153.68 / 4.105.08 / 5.49
2"60.331.65 / 2.422.77 / 3.993.91 / 5.525.54 / 7.59
2½"73.032.11 / 3.743.05 / 5.345.16 / 8.767.01 / 11.57
3"88.902.11 / 4.583.05 / 6.555.49 / 11.457.62 / 15.49
4"114.302.11 / 5.923.05 / 8.496.02 / 16.308.56 / 22.63
6"168.282.77 / 11.463.40 / 14.027.11 / 28.6610.97 / 43.15
8"219.082.77 / 14.983.76 / 20.258.18 / 43.1412.70 / 65.54
10"273.053.40 / 22.934.19 / 28.179.27 / 61.1512.70 / 82.68
12"323.853.96 / 31.684.57 / 36.499.53 / 74.9112.70 / 98.82

Chemistry

SS 347 composition

UNS
S34700
EN / W.Nr.
1.4550 · X6CrNiNb18-10
Density
7.96 g/cm³
SS 347 Stainless Steel chemical composition, % (ASTM A240)
ElementLimit, %Why it matters
C0.08 max
Mn2.00 max
P0.045 max
S0.030 max
Si0.75 max
Cr17.0 – 19.0
Ni9.0 – 13.0
Nb10×C – 1.00

Limits per ASTM A240; other product forms and specifications differ slightly. Your order's specification and edition govern.

0%5%10%15%20% Mn Cr Ni
Main alloying elements of SS 347 Stainless Steel: bars show the permitted range (ASTM A240).

Questions

About SS 347 pipes

SS 347 or SS 321 pipe?

Both are stabilised; SS 347 holds stabilisation better through welding and is somewhat stronger at temperature.

Is SS 347 pipe readily available?

Yes, in common sizes; larger sizes to order.

From enquiry to dispatch

How a SS 347 pipes order runs

  1. 01 EnquiryGrade, specification, size, quantity
  2. 02 ReviewChecked against your standard
  3. 03 InspectPMI, dimensions, TPI if required
  4. 04 CertifyEN 10204 3.1 / 3.2, heat traceable
  5. 05 ShipPacked and documented for the destination

Need SS 347 pipes?

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