ArcelorMittal and Gerdau said on Monday they were selling their Gallatin Steel U.S. joint venture to Nucor Corp for $770 million.

The Gallatin plant, located in northern Kentucky, produces flat-rolled steel and has an annual capacity of 1.8 million tonnes.

ArcelorMittal, the world's largest steel maker, said it expected the all-cash deal to close by the end of the year.

Nucor, which already operates four flat-rolled mills, said the purchase would increase its annual flat-rolled capacity by 16 percent to about 13 million tonnes and help it better serve customers in the pipe and tube segment.

That business has been growing in the United States thanks to demand from the oil and natural gas sector, where the pipes and tubes are used in hydraulic fracking.