Potato harvester made of Hardox® wear steel helps farmers harvest success

Located near Turkey’s southern coast, Öz-Eliş was founded in the 1990s as a supplier of repair and maintenance services for agricultural machinery. According to Mustafa Hayta, the second-generation manager of the company, they started to produce potato harvesting machines in 2005 in response to strong market demand. Nowadays, 80% of their production is concentrated in this area.

The company produces a two-row harvester model with a width of 1.5 m (5 ft) and, more recently, a four-row model with a width of 3 m (9.8 ft). While the two-row model is the most widely sold on that market, the company was determined to manufacture a bigger and more efficient model. It began extensive R&D testing that finally led the way to Hardox® wear-resistant steel.

The Öz-Eliş potato harvester is mounted on the back of a tractor and has blades at the front of the harvester to remove the potatoes under the soil and convey them to a screening belt at the back. The potatoes roll on the round bars of the belt, which are placed as horizontal strips.

In 2005, Öz-Eliş was using heat-treated ST37 (S235) mild steel on the harvester blades in the front of the two-row harvester. Later, they began to use ST52 (S355) steel to overcome frequent bending, wear and fracture problems. However, the desired results could not be achieved.

“We tried ST52 (S235) steel and we even tried to strengthen the steel by applying heat treatment, but still could not prevent the problems we experienced,” Hayta says. He began doing some research and came across Hardox®. Together with SSAB, the company conducted studies to determine the best product and grade to be used in the blades.

Hayta continues, “We decided that the most suitable products for us were Hardox® 450 and Hardox® 500. In sandy soil, we started using Hardox® 500, which is more resistant to abrasion, while in hard soil we started using Hardox® 450, which has sufficient abrasion and higher impact resistance. Hardox® 500 worked almost three times more efficiently than the heat-treated ST52.”

Thanks to the use of Hardox® wear steel, their challenges with wear, bending and cracks have disappeared. According to Hayta, the blades that offered 350 acres (17.5 hours) of service life in 10 mm (0.394 in.) thick ST52 can now offer 800 acres (40 hours) of service life with 8 mm (0.315 in.) thick Hardox® 500. 

“With the heat-treated ST52, we often experienced crack problems as well. This problem has disappeared with Hardox thanks to its unique toughness,” he says.

The company decided to develop a four-row potato harvester to gain efficiencies using less machinery and manpower.

The harvesting belt of their two-row harvester was made by lining heat-treated 41CrMo4 mild steel bars 1.5 m (5 ft.) wide and 13 mm (0.512 in.) in diameter. The width of the four-row harvester had to be 3 meters, which required using steel bars 3 m long (9.8 ft) and 13 mm (0.512 in.) in diameter.

“At that time, it was not possible to supply steel bars in the length we needed in one piece with local heat-treated solutions. We used 41CrMo4 steels in two parts – but we didn’t get the result we wanted,” Hayta says. “Heat-treated mild steel had many problems. There were serious differences between the hardness in one area and in another area. Moreover, the high hardness was only true for the surface of the material. Hardness decreased even further as it went from surface to center. The toughness of the material also decreased due to the heat treatment. These shortcomings caused problems, such as rapid abrasion, bending, cracks and fractures.”

Despite a three-year search, Öz-Eliş could not find a solution for 3-meter-long (9 ft. 10 in.) steel bars. That’s when SSAB engineers came into the picture.

“We talked to SSAB about how we could solve this problem. Since there were no ready-made materials in the desired sizes, SSAB produced special solutions to support our R&D work,” Hayta says. Steel round bars, 3 m (9.8 ft) in length and 13 mm (0.512 in.) in thickness, were custom made and delivered to Öz-Eliş so they could finalize their R&D. Hayta and team were so thrilled that they headed right for the fields to assemble the bars, not even waiting to paint them.