WASHINGTON—The U.S. Commerce Department said on Aug. 21 it had made a preliminary determination that large-diameter welded pipe from Canada, China, Greece, India, South Korea and Turkey was being dumped in the U.S. market.

The department said it found that the pipe, which is typically used to build oil and gas pipelines, was being sold at less than fair value at rates ranging from 3.45% to 132.63%.

In June, the department had made an initial finding that imports of the pipe from four of the countries—China, India, South Korea and Turkey—were being unfairly subsidized. It imposed preliminary duties that in the case of India ranged up to more than 500%.

In its announcement on Aug. 21, it said imports of the pipe from Canada were being dumped at a rate of 24.38%; from China at 132.63%; from Greece at 22.51%; from India at 50.55%; from Korea ranging from 14.97% to 22.21%; and from Turkey ranging from 3.45% to 5.29%.

Imports of the pipe from those six countries were valued at more than $720 million last year, the department said.

The U.S. probe into the imports was launched in March after a petition from a group of privately held U.S. producers. The probe covers welded carbon and alloy steel pipe larger than 16 inches (406.4 mm) in diameter.