Spain-based INDOX has switched to duplex LDX 2101® in the outer hulls of tankers used to transport LNG. Trucking company HAM (Spain) is keen to reinforce its image, preferring a completely stainless look in its road tankers: the tank surfaces, all stainless steel, bear the company name and logo but are otherwise uncoated. In 2007, HAM turned to INDOX with an order of eight tankers for transporting LNG or liquefied nitrogen. The conventional materials for such tankers, where the load is at -196C, are austenitic stainless steel EN 1.4301 / ASTM 304 on the inside and painted carbon steel on the outside. Together with their long-time stainless steel supplier Outokumpu, Teo Artigas, Technical Director of INDOX’s cryogenic unit researchers and engineers had in early 2007 replaced standard 1.4301/304 with continuously cold stressed (CCS®) coil of the same grade from Outokumpu to make the inner hull for cryogenic tank loads. CCS® coil has enhanced properties that make it suitable for tanks and containers, among many other applications: it is stronger, allowing for use of thinner materials, and as such makes for a more economical construction material. Designing new all-stainless tankers for HAM, INDOX wanted to find an alternative to 1.4301/304 in the outer hull as well. Again Outokumpu helped INDOX to find an optimal solution: INDOX replaced 1.4301/304 with Outokumpu’s proprietary duplex grade LDX 2101®. This grade features very low nickel content, but close to twice the strength of 1.4301/304 and somewhat better corrosion resistance. LDX 2101® is not applicable to tank loads in temperatures below -40C, so it cannot replace 1.4301/304 in the inner hull. Here INDOX continues to use 1.4301/304 CCS®. INDOX will complete the delivery of HAM’s eight LNG road tankers in the course of early 2008.
