EN 10216-3

EN -3 Seamless steel tubes for pressure purposes.

Fine grain steel tubes for pressure purposes are used in power engineering and other associated fields of industry. They are used as in elevated pressure installations and everywhere where it is necessary to assure the appropriate level of impact resistance of steel in different temperatures.

The pipes are manufactured with the diameters between 21,3 – 660 mm and with the wall thickness of up to 100 mm in the case of hot rolling, and with the diameters between 10,2 – 108 and with the wall thickness of up to12,5 mm in the case of cold drawing. The pipes are manufactured with TC1 tests (I requirement level) and TC2 (III requirement level). The pipes are manufactured for use in standard, elevated, and low temperatures as well as for special applications in low temperatures.

Steel grades used Standard quality
P355N, P460N, P620Q, P690Q
For elevated temperatures
P275NH, P355NH, P460HN, P620QH, P690QH
For low temperatures
P275NL1, P355NL1, P460NL1, P620QL, P690QL1
For special applications in low temperatures
P275NL2, P355NL2, P460NL2, P690QL2Details: Table 1
Dimensions and tolerances Details:  Table 2
Pipe lengths Pipes with precise lengths are manufactured with the following tolerance values:
– for pipes 0-6m -0/+10%
– for pipes 6-12m -0/+15%
– for pipes longer than 12m -0/to be negotiated
Tightness Pipes should be subject to water testing (7Mpa) or electromagnetic testing.
Straightness < 0,0015 of pipe length (below 3 mm per every meter of pipe length)
Tests Details:  Table 3
Table 1
Mechanical properties in room temperature
Pipe types
Steel grades
Thermal processing stage Mechanical properties during tensile testing
Upper yield limit or yield strength Re or Rp0,2  min for wall thickness T in  mm Tensile strength Rm for wall thickness T in mm Elongation A% min
<\=12 >12- <\=20 >20- <\=40 >40- <\=50 >50- <\=65 >65- <\=80 >80- <\=100 <\=20 >20- <\=40 >40- <\=65 >65- <\=100
MPa MPa 1 t
Fine grain alloy
P275NL, P275NL2, P355N, P355NH, P355NL1, P355NL2, According to PN--3
P275NL +N 275 265 255 245 235 390- 530 390- 510 360- 480 24 22
P275NL2 +N
P355N +N 355 345 335 325 315 305 490- 650 450- 590 450- 590 22 20
P355NH +N
P355NL1 +N
P355NL2 +N

 

Steel grades
CHEMICAL COMPOSITION (LADLE ANALYSIS)
C% max Si% max Mn% max P% max S% max Cr% max Mo% max Ni% max Al.cał% min Cu% max Nb% max Ti% max V% max N% max Nb+ Ti+ V% max
P275NL 0,16 0,40 0,50-1,50 0,025 0,020 0,30 0,08 0,50 0,020 0,30 0,05 0,040 0,05 0,020 0,05
P275NL2 0,015
P355N 0,20 0,50 0,90-1,70 0,025 0,020 0,30 0,08 0,50 0,020 0,30 0,020 0,05 0,040 0,10 0,12
P355NH
P355NL1 0,18
P355NL2 0
Table 2
Outside diameter and wall thickness tolerances
Outside diameter D mm Permissible deviations of outside diameter D Permissible deviations of wall thickness t depending on the T/D ratio
<\=0,025 >0,025
<\=0,050
>0,050
<\=0,10
>0,10
D<\=219,1 +\- 1% or =\- 0,5mm mm depending on which is greater +\- 12,5% or 0,4 mm depending on which is greater
D>219,1 =\- 20% =\- 15% =\- 12,5% =\- 10%

 

Inside diameter and wall thickness tolerance
Permissible deviations of inside diameter Permissible deviations of T for the given T/d ratio
d dmin <\-0,025 >0,025
<\=0,050
>0,050
<\=0,10
>0,10
+\- 1% or +\- 2mm depending on which is greater +2% +4mm
0
depending on which is greater
+\-20% +\-15% +\-12,5% +\-10%
For the outside diameter of D>\=355,6 mm, local deviation outside of the upper deviation limit by further 5% of the wall thickness T is permitted

 

Table 3
Inspection and test type Test frequency Test category
Mandatory tests Ladle analysis One per ladle 1 2
Tensile testing in room temperature One per every test pipe X X
Flattening test for D<600mm and the ratio of D<\=0,15 but T<\=40mm or ring testing for D>150mm and T <\=40mm X X
Rolling test on a mandrel bar for D<\=150mm and T<\=10mm or ring testing for D<\=114,3mm and T <\=12,5mm X X
Resilience testing at the temperature of 20 ºC X X
Tightness testing Every pipe X X
Dimensional testing X X
Visual inspection X X
NDT in order to identify longitudinal discontinuity Every pipe X X
Material identification for alloy steel X X
Optional tests Final product analysis One per ladle X X
Tensile testing at elevated temperatures (NH, NL, QL grades) One per ladle and for the same thermal processing conditions X X
Resilience testing at a temperature different than the standard test temperature One per every test pipe X X
X X
Wall thickness measurement at a distance from pipe ends X X
Non-destructive testing in order to identify transverse discontinuity Every pipe X X
Non-destructive testing in order to identify delamination X X