The World Trade Organization (WTO) referred to its court system a U.S. complaint against China over anti-dumping duties that China has imposed on certain types of electrical steel.

The issue now goes before a panel of the WTO's Dispute Settlement Body, a WTO official said. A panel usually takes between 12 and 18 months to report its findings.

The case involves Chinese duties on potentially hundreds of millions of dollars of "grain-oriented flat-rolled electrical steel" (GOES) made by AK Steel Corp of Ohio and Allegheny Ludlum of Pennsylvania.

The United States charges that China lacks sufficient evidence of unfair U.S. pricing practices or government subsidies to impose the duties. China slapped the duties on the Unite States and Russia in April last year after an investigation prompted by China's two largest silicon steel producers: Baosteel Group, the state-owned parent of Baoshan Iron and Steel , and Wuhan Iron and Steel Group, parent of Wuhan Steel.

Grain-oriented electrical steel, also known as grain-oriented silicon steel, is used for the cores of high-efficiency transformers, electric motors and generators. (Reuters)