HMF Group is a Danish manufacturer which makes truck-mounted cranes for its global customer base. For the past three years, the company has been utilising ArcelorMittal’s high strength Amstrong® Ultra steels to create lighter and stronger cranes. Truck-mounted cranes have very specific requirements which make material selection a critical step in the design process. To ensure it only receives high quality and uniform steel, HMF has a stringent qualification process which tests both steel quality and the supplier’s sustainability. The positive results ArcelorMittal has achieved in this process has seen cooperation between the two companies develop and grow stronger.
As well as having good reach and lifting capacity, truck-based cranes must be lightweight and fit within a very tight footprint. To meet these requirements, crane makers such as HMF require strong and tough steels which can be used in very low thicknesses.
ArcelorMittal’s Amstrong® Ultra range offers high yield and tensile strength, combined with excellent formability, toughness at low temperatures and fatigue resistance. This makes it an excellent choice for reducing the structural thickness and weight of crane components while improving their load-bearing capacity.
Some cranes can reach up to 35 metres and lift more than 95 tons
HMF began by approving Amstrong® Ultra 700MCL, as Mogens Kjærgaard, Category Manager for HMF Group, explains: “We started the approval process with a visit to the ArcelorMittal Bremen mill. After auditing the steelmaker and the mill, we received samples of Amstrong® Ultra 700MCL for testing. Following almost a year of trials we approved Amstrong® Ultra 700MCL for use in HMF cranes. I should also note that technicians and quality personnel from ArcelorMittal were present during every test to answer any questions.”
High strength steels such as Amstrong® Ultra are vital to ensure the crane has the reach and lift required. Some HMF cranes can reach over 35 metres and lift up to 95 tons. That makes the weight and strength of the lift’s components very important. “There are very small tolerances in our designs, and to meet those restrictions we needed a special material,” says Mogens Kjærgaard. “That meant the next step for HMF was to assess Amstrong® Ultra 960MCL. Since we approved the grade, we can use steel in thinner dimensions, generating cost and weight savings and securing market advantage.”
HMF tests the prototype of every crane they produce with at least 150,000 lifts. “This is a much higher number of lifts than they will perform in a normal lifetime,” notes Mogens Kjærgaard. “It enables HMF to have strong confidence in our cranes.”
Amstrong® Ultra gives HMF cranes the reach and lift required
ArcelorMittal is continuing to develop the Amstrong® Ultra range and HMF is closely involved as Mogens Kjærgaard explains: “It is critically important to HMF that ArcelorMittal has the R&D skills we need and that we have direct access to these personnel. An example is the development of stronger grades which is essential to the development of HMF. Our R&D team has already started working with ArcelorMittal to assess the new grades. This work has been disrupted due to the COVID-19 pandemic, but we will restart technical meetings as soon as it is practicable.”
With demand for its cranes rising rapidly, HMF started outsourcing the manufacture of non-core components about 15 years ago. “We have several partners around the world who carry out tasks such as machining,” says Mogens Kjærgaard. “To ensure the quality of our lifting solutions, partners are only allowed to use steels which HMF has approved. In Denmark, our steel supply chain is through Lemvigh-Müller a leading steel wholesaler and service partner to the Danish industry and building sector. But we don’t want to ship material to Denmark and then distribute it to our partners. Thanks to ArcelorMittal’s global presence and extensive distribution network, we can ensure our partners receive the same steel that we use in Denmark. And we appreciate that ArcelorMittal can deliver a high-quality and uniform product almost anywhere in the world. Material uniformity is very important, and ArcelorMittal is a very good partner.”
HMF distributes its cranes around the world
HMF cranes can be sent on a pallet and mounted to a truck by the customer
High strength steels enable HMF to make lighter cranes which can fit within a tight footprint