ArcelorMittal Sestao specialises in boron steels for agriculture and automotive

The ArcelorMittal Europe – Flat Products mill in Sestao (Spain) produces high quality boron steel grades. They are typically used by customers to create hard-wearing and abrasion resistant applications for agriculture, automotive, and industry. As one of the few compact strip processing (CSP) mills in Europe, ArcelorMittal Sestao is able to tightly control the steelmaking parameters to create very clean steels and act as a trial production site for new grades.

ArcelorMittal Sestao produces the most comprehensive range of boron grades of any mill in the ArcelorMittal network. The main application for these incredibly strong steels is in agricultural disks. The high toughness of boron steels is obtained after quenching and ensures the disks can withstand the hard wear they endure from contact with soil and stones.

Automotive lightweighting with boron steels

Increasingly, boron steels are being used to form small welded tubes which are used in many structural applications, and in the automotive sector. With their excellent toughness and high tensile strength, boron steel tubes offer carmakers new lightweighting possibilities. Key applications include anti-roll bars, steering assemblies, and exhaust systems.

In addition to boron grades, ArcelorMittal Sestao also produces micro-alloyed steels (high strength low alloy), case hardening and high carbon steels, ferrite-bainite and Dual Phase (DP) steels for the automotive market. Sestao offers a complete range of formats and thicknesses with a special focus on low thickness and tight tolerances to meet market demand.

One of the advantages of ArcelorMittal Sestao is the compact nature of its operations, as Atish Kumar, director of product development and quality, explains: “Like other high carbon steels, the production of high quality boron steels requires good temperature control. If the slabs are cooled to room temperature, brittle fracture may occur. At ArcelorMittal Sestao, we cast a very thin slab at high speed. That is reheated in a tunnel furnace within 15 to 20 minutes of casting and is ready for direct rolling

This novel casting method ensures very good internal cleanliness and almost no central segregation. “The thermal homogeneity of our thin slabs, and one of the strongest rolling mills in the ArcelorMittal network, enable Sestao to produce boron grades in very low thicknesses and with tight tolerances,” says Atish Kumar. “These properties are fundamental to the long service life of the end products our customers produce.”

Customers appreciate Sestao’s very clean and precise steels. One such customer is Flinsa, a Spanish producer of steel tubes and strips which are used in a range of applications including automotive. “The regularity in thickness of the steels produced at ArcelorMittal Sestao, especially in micro-alloyed and boron steels, is very important,” notes Gregorio Pérez Gil, CEO of Flinsa. “The high strength and low thicknesses of these products is also critical for us. We appreciate the strong commitment Sestao has to quality and service towards us as a customer.”

Flexible approach and size ideal for product testing

Another key advantage of Sestao’s compact size is its ability to produce small batches of new grades. “This gives ArcelorMittal’s Global R&D product teams a great platform to test new concepts fast and flexibly,” notes Atish Kumar. “Our size also enables us to proceed quickly in the development of new products such as 27MnCrB5 and 45MnB4 which were commercialised recently. When necessary, we can have a new product ready for full production within three or four months of the customer’s initial request. Developing new products and satisfying our customers is the basis of the current business plan for Sestao.”

ArcelorMittal Sestao is continuing to upgrade its facilities and add new R&D process equipment. The aim is to develop new products and commercial offers. “2018 is a critical year for us,” says Atish Kumar. “We will commission new process technologies and already have a number of product trials scheduled. An ambitious and vigorous testing process is also planned to prove the metallurgical advantages of ArcelorMittal Sestao.”

ArcelorMittal’s boron steel offer

Boron steels are extremely hard thanks to the inclusion of carbon and a small amount of boron to improve their hardenability. This makes them exceptionally resistant to abrasion and ideally suited to the manufacture of agricultural disks, welded tubes for automotive, and applications such as standalone and truck-mounted cement mixers.

ArcelorMittal’s boron steel grades are a cost-effective solution to prolong the lifetime of final products. Hardened via a boron quenching process and a controlled hot rolling thermo-mechanical treatment, our boron steels exhibit:

• A remarkable degree of hardness
• A uniform microstructure
• Outstanding mechanical loading
• Excellent resistance to abrasive wear.

ArcelorMittal produces a complete range of boron steels at five mills in Europe: Avilés and Sestao in Spain; Dunkirk and Fos-sur-Mer in France; and most recently, Galati in Romania. They all produce complementary products with a specialisation for customers in their local markets.

For more info on ArcelorMittal’s boron steel offer visit: industry.arcelormittal.com/boronsteels