TUBES FOR PRESSURE SERVICE. ALLOY FINE STEEL TUBES. (PN-EN 10216-3)

Manufacturing and purpose
It is produced in diameters from 21.3 - 660 mm with wall thicknesses up to 100 mm as hot rolled, and in diameters from 10.2 - 108 mm and wall thicknesses up to 12.5 mm as cold drawn. The pipes are manufactured with TC1 (I requirement level) and TC2 (III requirement level) tests. Fine grain steel pipes for pressure purposes are used in situations of increased demand for the impact properties of steel, which is obtained by using steel with a ferritic grain size of 6 and smaller.

Steel grades used
Depending on the thermal conditions, the following steels are used:

for basic applications - steels P355N, P460N, P620Q, P690Q
for applications at elevated temperatures - steels: P275NH, P355NH, P460HN, P620QH, P690QH
for applications in low temperatures - steels: P275NL1, P355NL1, P460NL1, P620QL, P690QL1;
for applications in especially low temperatures - steels: P275NL2, P355NL2, P460NL2, P690QL2

Dimensions
Outside diameter: 10.2 to 711 mm
Wall thickness: up to 100 mm
Length: 6 - 12 m

Research and requirements
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.

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 ° C, leak test, dimensional control, visual inspection, NDT to detect longitudinal discontinuities, material identification for alloy steels