Large Indian steel companies won't be affected by a U.S Commerce Department plan to levy antidumping duties on steel pipe imports, but small manufacturers could be hit over the long term as they export a sizeable portion of their output, industry executives said Thursday.

Steel majors such as JSW Steel Ltd. (500228.BY), Welspun Group and PSL Ltd. (526801.BY) have manufacturing plants in the U.S. and don't export to the country, company executives said.

"I don't see any impact of this on Welspun," Akhil Jindal, corporate affairs director at Welspun Group, said, adding that the company doesn't export to the U.S as it has a plant with an annual manufacturing capacity of 350,000 metric tons there.

PSL, another prominent steel maker, has also established a 250,000-ton steel pipe manufacturing plant in the U.S.

However, small steel firms do export to the U.S. Indian companies exported steel pipes worth $64.6 million in 2011 to the U.S., marginally down from $64.9 million a year earlier.

On Tuesday, the U.S. Commerce Department set tariffs on imports of steel pipes from India, Vietnam, Oman and the United Arab Emirates, following complaints by U.S manufacturers that imported steel pipes were being sold at below-market rates.

In addition, the department said, it planned to levy antidumping duties on the product from all four countries, after determining whether they were selling below U.S. fair value.

Before the duties can go into effect, the independent U.S. International Trade Commission has to decide whether U.S. producers are being harmed by the imports.

Write to Debiprasad Nayak at debi.nayak@dowjones.com and Saurabh Chaturvedi at saurabh.chaturvedi@dowjones.com