European stainless-steel producers including Outokumpu Oyj and Acerinox SA may win tariffs against competitors from China, Taiwan and Indonesia over suspected price dumping.

The European Union opened a probe into whether Chinese, Taiwanese and Indonesian exporters of flat-rolled stainless steel sell it in Europe below cost.

The inquiry specifically covers hot-rolled, stainless-steel sheets and coils, which are used for other kinds of steel and for tubes. EU imports of the product from around the world were worth almost 900 million euros ($1 billion) last year, according to European industry group Eurofer.

The investigation will determine whether shipments from China,...