Steel  type

Steel  grade

Standard

Specification

Boiler Tube

TP304H,TP310H,TP316H,

TP321H,TP347H,TP347HFG

ASTM A213,ASME SA213,

EN10216-5,

OD: 33.40-273.0mm
WT: 2.11-20.0mm

Marine Tube

P304H,TP304L,TP347H,
TP321, TP321H,

ASTM A312, ASTM A269,
JIS G3459

OD: 6.0-273mm
WT: 0.5-16.0mm

Instrumentation Tube

TP304,TP304L,TP316,
TP316L,TP317L,TP321,

GB/T14976,EN10216-5,
DIN17456,DIN17458,
ASTMA269,JISG3459

OD: 6-76.0mm
WT: 0.5-6.0mm

General Tube

TP304,TP304L,TP304H,
TP316,TP316H,TP316Ti,
TP316L,TP321,TP316Mo

EN10216-5,
DIN17456,DIN17458,   ASTMA312,JISG3459

OD: 10.0-830.0mm
WT: 1.65-45.0mm

Duplex Tube

S31803; S32205;S31500; S32750

ASTM A789

OD: 12.0-219.0mm
WT: 0.5-14mm

ASTM A790

OD: 10.0-273.0mm
WT: 0.5-20mm

Nickel-base alloy

N08825,N08904,
N08028,N08800

ASME SB 163, ASTM B 163,
ASME SB423, ASTM B423,
 ASME SB407, ASTM B407,
ASME SB668, ASTM B668

OD: 16-273mm
WT: 1.65-20.0mm

Note: Marine tubes could be verified by ABS,BV,CCS,DNV,GL,LR,KR

Permitted variations in wall thickness

Tolerance，% from Normal

NPS Designator

Over

Under

1/8 to 21/2nincl.,all t/D ratios

20

12.5

3 to 18 incl.,t/D up to 5% incl.

22.5

12.5

3 to 18 incl.,t/D 〉5%

15

12.5

20 and larger,welded,all t/D ratios

17

12.5

20 and larger,seamless,t/D up to 5% incl.

22.5

12.5

20 and larger, seamless,t/D〉5%

15

12.5

 Where:      t= Nominal Wall Thickness   D= Ordered outside diameter