Semitrailer OEM Mantella took its trailer design into the stratosphere with the new Hardox® steel, Hardox® 500 Tuf. The company implemented major design advances in the use of high-strength steels produced by SSAB. As a result, it revolutionized the design of its innovative Stratosphere tipper trailer and saw the benefits skyrocket.
The combined weight reduction of using abrasion-resistant Hardox® 500 Tuf in the body and Strenx® 960 in the chassis is 510 kg (1,124 lbs.) compared to the previous design. This translates to an increased payload of 510 kg (1,124 lbs.) on every trip. And higher load capacity is what practically every customer is looking for. The new trailer design won the international Swedish Steel Prize 2018.
Mantella’s tipper trailer is more than 500 kg (1,102 lbs.) lighter than a conventional design. The U-shaped body in Hardox® 500 Tuf weighs 365 kg (805 lbs.) less and the chassis in Strenx® 960 is 145 kg (320 lbs.) lighter. The horizontal bends increase the stiffness of the body, preventing buckling when tipping.
Mantella S.r.l. is a family business located in Lamezia Terme in southern Italy. The company has set ambitious goals to design stronger and lighter semitrailers that will carry larger payloads, while saving fuel and reducing CO2 emissions at the same time. Reducing emissions is important since road transport accounts for 17.5% of overall gas emissions in Europe, according to the European Environment Agency. By 2050, these emissions will need to be at least 60% lower than in 1990 and be firmly on the road towards zero.
“By lowering fuel consumption and CO2 emissions per ton kilometer we are contributing to a more sustainable world. To successfully develop this lightweight tipper trailer, the entire company has been involved – design engineers, production, management and purchasers. The Stratosphere trailers make use of all the benefits obtainable from SSAB’s high-strength steel grades like Hardox 500 Tuf. Naturally, we are also in the process of implementing stronger and lighter tipper trailer design solutions for our other trailer series,” says Gregorio Mantella, Plant Director at Mantella.
Stratosphere trailers from Mantella have tipper trailer bodies made of Hardox® 500 Tuf wear plate. This new Hardox® grade delivers longer wear life while having the same toughness as the previously used Hardox® 450 grade.
Thanks to the higher wear resistance of Hardox® 500 Tuf, Mantella could reduce plate thickness by 1 mm (0.039"). This saves on average 365 kg (805 lbs.) of body weight.
Reducing the thickness is possible thanks to the increased hardness in combination with the high toughness and dent resistance that comes with Hardox® 500 Tuf. Even after many years of use, the steel will be thick enough as not to compromise the integrity of the body.
Hardox® 500 Tuf combines the best properties from the Hardox® 450 and Hardox® 500 wear steel grades. It has an unusually narrow hardness window of 475-505 HBW. Its relative wear life can be 30-50% longer compared with Hardox® 450. The high toughness gives excellent resistance against dents and cracks when the steel is hit by sharp and heavy objects. Hardox® 500 Tuf has a guaranteed impact toughness of 27 J at 20°C (20 ft-lb at 4°F) and, for 20 mm (0.79") plate, a typical value of 45 J at 40°C (20 ft-lb at 4°F).
When using a thinner material, the body of the semitrailer has to be designed in a way that ensures the stiffness and overall stability of the body. When raising a fully loaded trailer body with a front mounted hydraulic cylinder, the body experiences high stresses. If it’s not designed correctly it could result in a sudden buckling of the sides.
To counteract this, Mantella incorporated a number of trailer design changes such as adding horizontal bends to the side panels. This gives the necessary stiffness to the entire body. The hydraulic cylinder attachment, top rails, rear frame and tipping pivots have also been redesigned for added torsional stiffness.
In addition to using Hardox® 500 Tuf, Mantella challenged conventions when it decided to produce the longitudinal beams of the chassis by advanced bending of a single flat strip of Strenx® 960 instead of welding.
The new trailer chassis in the Stratosphere series weighs in on par with aluminium, and has all the durability, fatigue strength and production advantages of steel. Mantella now not only offers its customers a chassis that is 145 kg (320 lbs.) lighter. It also possesses superior mechanical properties and improved road handling.
“End-users of the Stratosphere 3.0 point out that with the same workload as previous models, they can achieve a greater payload, more on-road stability with a full load and a significant reduction in fuel and tire consumption,” Mantella said.
This is what we call “EcoUpgraded”.
With the help of software like SSAB’s WearCalc, you can calculate the wear rate already before the tipper body is produced. The different colors in the image show the stresses caused by sliding wear after unloading the tipper. Data from the calculations will provide the manufacturer with recommendations on ideal material selection and upgrades and on wear design.
“The increased abrasion resistance of Hardox 500 Tuf allows us to use a thinner plate and keep the same excellent service life”
”Since we upgraded the steel to Hardox 500 Tuf wear-resistant steel, we have increased the useful life of our dumpers by at least 40 percent.”