AK Steel had its most difficult quarter this year in the third quarter, a reflection on the state of the economy, said the company’s top executive in an earnings conference call Tuesday to investors.

AK Steel Corp. posted Tuesday a quarterly net loss of $60.9 million on higher plant maintenance costs, tax expenses and lower market prices for selling steel.

This compares to a net loss for the third quarter last year of $3.5 million, according to the Butler County steelmaker.

“Challenging domestic and global economic conditions continue to weigh on shipping volumes and prices,” said James Wainscott, chairman, president and chief executive officer of AK Steel, in a statement with the release. “Additionally, while we expect to enjoy lower raw material costs in the future, we are still working through some higher cost raw material inventories.”

Shipments increased to 1,363,500 tons from the quarter before, but the average selling price was $1,073 per ton, or seven percent lower than the second quarter, AK Steel said.

AK Steel had $28.5 million this last quarter in planned major maintenance outage costs for its Ashland Works blast furnace and Middletown Works hot strip mill, the company said. A year ago, outage costs were $1.7 million. The company also recorded in the third quarter an approximately $33 million income tax expense valuation, a non-cash adjustment.

The automotive sector, which uses AK Steel’s carbon and stainless steel products, is a bright spot for the company, Wainscott said in the conference call. September’s seasonally adjusted annual sales rate for U.S. vehicle production reached 14.9 million vehicles, the highest level since March of 2008. Wainscott said in the call AK Steel is gaining market share in the automotive steel business — auto builds are tracking 15 percent higher this year and AK Steel’s shipments to auto customers are coming in 20 to 25 percent higher, he said.

The gains in the auto sector are being offset by sluggish growth in AK Steel’s other market segments. Demand for steel for the infrastructure and manufacturing, and distributor and converter markets is flat and highly competitive, Wainscott said.

AK Steel hopes that its future international sales of electrical steels will be helped by the announcement last week from the World Trade Organization. The World Trade group affirmed a ruling that China was unjustified in imposing duties on AK Steel’s products.

AK Steel is based in West Chester Twp. and operates multiple steel plants, including Middletown Works. It is Middletown’s largest employer.