Kelly Attachments relies on Hardox® round bars

Hardox® round bars are delivered heat-treated and ready to use. The hardness of Hardox® 400 round bar is typically 400 HBW. It’s also hard from the surface to the core. Even though it’s a hard material, the low carbon, homogeneous microstructure makes it machinable with regular workshop equipment.

The quick coupler from Kelly Attachments uses five pins, four fixed and one that is removed when changing attachment. The pins are turned to the right diameter in a CNC lathe.

“With Hardox I can take the bar, put it in the lathe, take it out and it’s a finished part with a fine surface. I don’t have to do anything with it, just put on some rust protection. It’s a hard material and that is what we are looking for. Still, our machines can handle it fine – we just have to turn over the tool inserts more often.That’s no big deal compared to the wear performance we get with the Hardox round bars,” says Kelly.

Kelly Attachments has so far made well over 1,000 quick couplers that are all Hardox®. The pins are Hardox® round bar and the body of the quick coupler is made of Hardox® wear plate. The couplers have been on the market for about three years without any need for pins to be replaced, and without any other problems for that matter.

It goes to show that design as well as manufacturing processes and choice of material more than fulfil the customers’ demands.

Buckets from Kelly Attachments also use Hardox® wear plate for the side cutters and for the lip with teeth that are machined from one single piece of Hardox®. The solid teeth give excellent breakout force when working in hard ground.

Hardox® round bars come in diameters of 40–100 mm (1.575–3.937 in.) and lengths up to 5,000 mm (196.85 in.). Other dimensions are also available and under development as AR 400 and AR 500 bars. AR 500 round bars are available in diameters of 20–160 mm (0.786–6.298 in.). The dimensional tolerances for diameter and roundness are very tight and consistent, ensuring efficient and repeatable production.

The low carbon equivalent in Hardox® round bars gives the material high weldability compared to other steels such as 4140 or 42CrMo4V steel. Welding can be performed without pre-heating.