ALUMINIZED STEEL
ALUMINISED STEEL TYPE II
The use of Aluminized Steel Type 2 with its bi-layer Al/Al-Fe protective metallic coating in drainage pipe service increases the range of environmental conditions and the Corrugated Steel Pipe (CSP) service life attained within those conditions. The application of Type 2 within the recommended 5 – 9 pH range and the ≥ 1500 ohm•cm resistivity range, indicated below, covers most pipe environments. Based on field studies of 43 years, 16 gauge Type 2 service life in these ranges is estimated at 75 years. Based on the 50 year durability assessment, 16 gauge Type 2 has a service life of 100 years for pH 5 – 9 and resistivity ≥ 5000 ohm•cm. In the narrower pH range 6 – 8 with resistivity ≥ 1500 ohm•cm a 100 year service life is also expected. The duplex Type 2 coating exhibits spontaneous passive film corrosion protection in the aluminum layer and inherent corrosion/abrasion protection in the Al-Fe intermetallic alloy layer. The Al-Fe alloy layer provides a major portion of coating protection.
The use of Aluminized Steel Type 2 with its bi-layer Al/Al-Fe protective metallic coating in drainage pipe service increases the range of environmental conditions and the Corrugated Steel Pipe (CSP) service life attained within those conditions. The application of Type 2 within the recommended 5 – 9 pH range and the ≥ 1500 ohm•cm resistivity range, indicated below, covers most pipe environments. Based on field studies of 43 years, 16 gauge Type 2 service life in these ranges is estimated at 75 years. Based on the 50 year durability assessment, 16 gauge Type 2 has a service life of 100 years for pH 5 – 9 and resistivity ≥ 5000 ohm•cm. In the narrower pH range 6 – 8 with resistivity ≥ 1500 ohm•cm a 100 year service life is also expected. The duplex Type 2 coating exhibits spontaneous passive film corrosion protection in the aluminum layer and inherent corrosion/abrasion protection in the Al-Fe intermetallic alloy layer. The Al-Fe alloy layer provides a major portion of coating protection.
