With the introduction of Lean Duplex 2 stainless steel, Brenner Tank LLC has trimmed about 700 pounds from the typical DOT407 chemical tank trailer constructed of 316 stainless steel.
The weight savings come from being able to fabricate these second-generation Lean Duplex tanks from 12-gauge material. Tanks constructed of first-generation Lean Duplex--as well as 316 stainless steel--usually are specified with 10-gauge shells. Lean Duplex 2 tank trailers with 12-gauge shells are built under DOT Special Permit.
”We received the permit in early 2010, and we have built 17 DOT407 trailers so far this year with Lean Duplex 2,” says John Cannon, vice-president of engineering for Walker Group Holdings. “We have an order for 10 more, and we expect demand to continue growing as more fleets learn about the benefits of this stainless steel.
”A key motivation for moving forward with Lean Duplex 2 was the realization that the 2010 diesel truck engines would add more than 800 pounds to a tractor trailer rig. We knew that Lean Duplex 2 could offset much of the engine weight gain. In addition, Lean Duplex 2 has better tensile and yield strength. Yield strength alone is 2 ½ times greater than 316 stainless steel. Fatigue characteristics are good, and Lean Duplex 2 does very well with temperature fluctuations.”
Produced by Outokumpu, a leading stainless steel manufacturer based in Finland, Lean Duplex 2’s official designation is LDX 2101. Cargo tanks built of this material can handle any chemical currently hauled in a tank constructed of 316 stainless steel. Sulfuric acid is one of the few products that cannot be transported in a Lean Duplex 2 tank.
Cargo tanks built of Lean Duplex 2 are very robust, according to Cannon. Tanks built of this stainless steel should be able to remain in service well in excess of 20 years, as long as they are properly used and maintained, he says.
Brenner Tank introduced its first Lean Duplex chemical tank trailers in 2007, and about 100 of these units are in service today. These first-generation tanks were fabricated from 10-gauge Lean Duplex stainless steel and weighed roughly the same as a comparable DOT407 tank made of 316 stainless steel.