MIXED STEEL - NON-ALLOY AND ALLOY STEEL PIPES FOR PRESSURE SERVICE, OPERATING AT LOW TEMPERATURE (STANDARD PN-EN 10216-4)

Manufacturing and purpose
Pipes are used mainly in the power industry and its related industries, they are used in apparatus and devices operating at low temperatures and under increased pressure.
They have a low tendency to cracking at low temperatures due to the appropriate impact strength.
It is produced in diameters from 21.3 - 660 mm with wall thicknesses up to 100 mm as hot rolled, while in the diameter range from 10.2 - 108 mm and wall thicknesses up to 12.5 mm as cold drawn, and the production takes place in in the scope of TC1 and TC2 tests

Steel grades used
P215NL, P255QL, P265NL, 26CrMo4-2, 11MnNi5-3, 13MnNi6-3, 12Ni14, X12Ni5, X10Ni9

Dimensions
Outside diameter: 10.2 to 711 mm
Wall thickness up to: 100 mm
Length: 6 and 12 m, over 12 m by agreement

Research and requirements
Tests: melt analysis, tensile test at room temperature, flattening test for D <600mm and ratio D <= 0.15 but T <= 40mm or ring breaking test for D> 150mm and T <= 40mm, mandrel expansion test for D <= 150mm and T <= 10mm or ring test for D <= 114.3mm and T <= 12.5mm, impact test at 20 ºC, leak test, dimensional inspection, visual inspection, NDT to detect longitudinal discontinuities, material identification for alloy steels.

Straightness: <0.0015 pipe length (less than 3mm per meter of pipe).
Tightness: pipes should be subjected to a water test (7Mpa) or electromagnetic testing.