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Stainless Steel · Pipes · ASTM A312 / ASME SA312 TP304H

SS 304H Stainless Steel Pipes

In short: SS 304H pipe to ASTM A312 TP304H (or A376 for central-station power piping) has 0.04–0.10% carbon and a coarse grain, giving the creep strength needed for steam and process lines above about 500 °C.

S30409
UNS number
7.93
density, g/cm³
3.1 / 3.2
EN 10204 certificates
3
SS 304H product forms
Quote SS 304H pipes →Sizes and weights
SS 304H pipe weight by sizeCalculated at 7.93 g/cm³: ½" 1.28 kg/m; ¾" 1.70 kg/m; 1" 2.53 kg/m; 1¼" 3.42 kg/m; 1½" 4.09 kg/m; 2" 5.50 kg/m; 2½" 8.72 kg/m; 3" 11.41 kg/m; 4" 16.24 kg/m; 6" 28.55 kg/m; 8" 42.98 kg/m; 10" 60.92 kg/m; 12" 74.63 kg/m. SS 304H pipe weight by size7.93 g/cm³ ½": 1.28 kg/m½"¾": 1.70 kg/m¾"1": 2.53 kg/m1"1¼": 3.42 kg/m1¼"1½": 4.09 kg/m1½"2": 5.50 kg/m2"2½": 8.72 kg/m2½"3": 11.41 kg/m3"4": 16.24 kg/m4"6": 28.55 kg/m6"8": 42.98 kg/m8"10": 60.92 kg/m10"12": 74.63 kg/m12" 74.6 NPS, Sch 40S · kg/m
Calculated values for estimating; actual weights vary within tolerances.

Why this combination

Why steam lines use SS 304H pipe

Carbon 0.04–0.10% for elevated-temperature strengthCoarse grain size (ASTM No. 7 or coarser) for creep resistanceHigher ASME allowable stresses at high temperature than SS 304LSpecified for boiler, superheater and furnace service

Pressure piping in the creep range is sized from code allowable stresses at temperature. SS 304H's guaranteed carbon and grain size earn higher allowables than SS 304L, so walls can be thinner.

A376 is written for high-temperature central-station service and is often specified for power piping; A312 covers general high-temperature pipe.

Specification

How to specify SS 304H pipes

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

SS 304H pipe cross-section, NPS 6 Sch 40S Engineering drawing showing outside diameter 168.28 mm and wall thickness 7.11 mm (ASTM A312 TP304H). Wall thickness is exaggerated for clarity. OD 168.28 mm WT 7.11 mm NPS 6SCH 40S ASTM A312 TP304H
SS 304H pipes: ASTM A312 / ASME SA312 TP304H (seamless & welded)
Specification
ASTM A312 / ASME SA312 TP304H (seamless & welded); A358 EFW
UNS
S30409
EN / W.Nr.
1.4948
Grade marking
TP304H
Heat treatment
Solution annealed; grain size ASTM 7 or coarser

Sizes and weights

SS 304H pipes sizes, weighed at 7.93 g/cm³

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

SS 304H pipe: wall (mm) / weight (kg/m) at 7.93 g/cm³, ASME B36.19M
NPSOD mmSch 5SSch 10SSch 40SSch 80S
½"21.341.65 / 0.812.11 / 1.012.77 / 1.283.73 / 1.64
¾"26.671.65 / 1.032.11 / 1.292.87 / 1.703.91 / 2.22
1"33.401.65 / 1.312.77 / 2.113.38 / 2.534.55 / 3.27
1¼"42.161.65 / 1.672.77 / 2.723.56 / 3.424.85 / 4.51
1½"48.261.65 / 1.922.77 / 3.143.68 / 4.095.08 / 5.46
2"60.331.65 / 2.412.77 / 3.973.91 / 5.505.54 / 7.56
2½"73.032.11 / 3.733.05 / 5.325.16 / 8.727.01 / 11.53
3"88.902.11 / 4.563.05 / 6.525.49 / 11.417.62 / 15.43
4"114.302.11 / 5.903.05 / 8.456.02 / 16.248.56 / 22.55
6"168.282.77 / 11.423.40 / 13.977.11 / 28.5510.97 / 42.99
8"219.082.77 / 14.933.76 / 20.178.18 / 42.9812.70 / 65.30
10"273.053.40 / 22.844.19 / 28.069.27 / 60.9212.70 / 82.37
12"323.853.96 / 31.564.57 / 36.359.53 / 74.6312.70 / 98.45

Chemistry

SS 304H composition

UNS
S30409
EN / W.Nr.
1.4948 · X6CrNi18-10 (related)
Density
7.93 g/cm³
SS 304H Stainless Steel chemical composition, % (ASTM A240)
ElementLimit, %Why it matters
C0.04 – 0.10
Mn2.00 max
P0.045 max
S0.030 max
Si0.75 max
Cr18.0 – 20.0
Ni8.0 – 10.5

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 304H Stainless Steel: bars show the permitted range (ASTM A240).

Questions

About SS 304H pipes

A312 or A376 for SS 304H pipe?

A376 for power-station piping where the spec calls for it; A312 for general high-temperature process piping.

Can SS 304/304H dual pipe be supplied?

Yes, where the heat meets both grades' requirements.

From enquiry to dispatch

How a SS 304H 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

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