Seamless Austenitic Stainless Steel Tubes for
High-Temperature Service Grades TP304H, TP347H, TP321H
We supply ex mill and ex stock: seamless austenitic stainless steel
pipes in TP304H, TP347H and TP321H
Main use of the high alloy material is for boiler tubes in power
stations and refineries
❚ high creep rupture strength above 500°C
❚ excellent resistance to high-temperature corrosion
❚ excellent processing characteristics
Stock standard: ASTM/ASME A/SA 312/376, EN10216-5, TC1, IC-Test
according to ASTM A262 Practice E, NACE MR0175; mill
inspection certificate EN DIN 10204/3.1
Grades: TP304/304H (1.4301, 1.4948); TP321/321H (1.4541, 1.4878);
TP347/347H (1.4550, 1.4912)
Please ask us also for TP316 with C > 0,04 %.
Supplementary requirement (upon request): TP347/347H with
stabilizing heat treatment at 900°C for 30 minutes.
The term pipe covers a specific range of sizes laid down by ANSI
specifications. Any sizes not covered by these specifications are
tube. Stainless Steel Pipe dimensions determined by ASME B36.19
covering the outside diameter and the Schedule wall thickness. Note
that stainless wall thicknesses to ANSI B36.19 all have an ‘S’
suffix. Sizes without an ‘S’ suffix are to ANSI B36.10 which is
intended for carbon steel pipes.
Seamless and Welded
ASTM A312: Seamless and straight-seam welded austenitic pipe intended
for high temperature and general corrosive service. Filler metal
not permitted during welding.
ASTM A358: Electric fusion welded austenitic pipe for corrosive and/or
high temperature service. Typically only pipe up to 8 inch is
produced to this specifi cation.
Addition of fi ller metal is permitted during welding.
ASTM A790: Seamless and straight-seam welded ferritic/austenitic
(duplex) pipe intended for general corrosive service, with a
particular emphasis on resistance to stress corrosion cracking.
ASTM A409: Straight-seam or spiral-seam electric fusion welded large
diameter austenitic light-wall pipe in sizes 14˝ to 30˝ with walls
Sch 5S and Sch 10S for corrosive and/or high temperature service.
ASTM A376: Seamless austenitic pipe for high temperature applications.
ASTM A813: Single-seam, single- or double- welded austenitic pipe for
high temperature and general corrosive applications.
ASTM A814: Cold-worked welded austenitic pipe for high temperature and
general corrosive service.
Note: Welded pipes manufactured to ASTM A312, A790 and A813 must be
produced by an automatic process with NO addition of filler metal
during the welding operation.
Welded pipe specifications
Usually it will be to ASTM A312. If it is to ASTM A358 then there
are various Classes available as shown below. The Class Number
dictates how the pipe is welded and what non-destructive tests:
Class 1: Pipe shall be double welded by processes employing filler
metal in all passes and shall be completely radiographed.
Class 2: Pipe shall be double welded by processes employing filler
metal in all passes. No-radiography is required.
Class 3: Pipe shall be welded in one pass by processes employing
filler metal and shall be completely radiographed.
Class 4: Same as Class 3 except that the welding process exposed to
the inside pipe surface may be made without the addition of filler
Class 5: Pipe shall be double welded by processes employing filler
metal in all passes and shall be spot radiographed.
Markings on pipe
The full identifi cation of the pipe should be continuously marked
down its whole length, including:
Nominal Pipe Size (Nominal Bore)
Schedule (Wall Thickness)
Method of Manufacture (Seamless or Welded)
Manufacturer’s Name or Symbol