It is well known that both trailer manufacturers and transport operators can benefit financially, but the advantages in terms of lower CO2 emissions should also be recognized. 

When looking into the financial benefits for the trailer manufacturer, it is important to consider all aspects that affect the overall production economy. Simply comparing price level per ton for different steel grades fails to provide an accurate picture of the manufacturing cost level. In most cases, reducing the sheet thickness will provide a significant cost reduction in both the processing of the material and material cost. Even if the price per ton is higher for HSS, less steel is consumed due to the weight reduction. Using thinner gauges in the workshop allows the cost of cutting, bending and welding to be reduced. Laser cutting in high-strength steel is no different from cutting in mild steel, and the producer will decrease the cutting time due to the thinner gauge. In most cases, welding thinner material provides the largest cost reduction due to the reduction of consumables and the opportunity to increase the welding speed. Introducing HSS with good bendability can also reduce the number of welds needed. Profiles in HSS generally do not require greater force to bend than a profile in a thicker gauge made from conventional steel.  However, the spring-back of HSS is greater compared to conventional steel and needs to be compensated for in the process. 

To give a better insight into these issues, a comparison between the production costs of a traditional flatbed trailer chassis and a lightweight solution manufactured from HSS was performed. The traditional trailer chassis studied here is manufactured from hot-rolled standardized I-beams, which are cut and welded back together in the goose-neck region to create the height transition of the main beams. The cross-members consist of bent profiles welded to the longitudinal beams and there are also some side-wing profiles to support the floor. The side rail profiles are manufactured from standardized U-beams. All parts are produced from a S355-steel grade. In the lightweight solution the hot-rolled I-beam has been replaced by a laser-cut and welded longitudinal I-beam manufactured from HSS. Upgrading the traditional chassis by introducing HSS allows for a reduction in the thickness of all major structural parts and in the weight of the chassis by up to 1,500 kg. 

In addition to the weight reduction, a production cost reduction of up to 30% can be observed (see graph). Cost have decreased for both cutting and welding operations. In this case, a slight increase in the bending cost was observed. Additional bending is required due to design issues, necessitating the introduction of new profile cross-sections. A 30% cost reduction offers obvious benefits for the producer, and when combined with a more attractive lightweight trailer, great market advantages can be expected. It is also noteworthy that this study was conducted on an existing chassis whose structural parts were primarily composed of hot-rolled profiles. If the existing traditional chassis had been produced from welded beams, even greater cost savings could have been achieved.
 

Comparison of production cost of conventional and lightweight trailer chassis including welding (1), bending (2), cutting (3) and material (4) costs. Using thinner material gives cost reductions in both welding and cutting operations. Welding, bending and cutting costs depend on labor costs in each market, which can vary.