Struggling steel pipe makers including United States Steel Corp, Tenaris SA subsidiary Maverick Tube Corporation, JMC Steel Group Inc's Energex Tube, Russia's TMK IPSCO and France's Vallourec Star filed the case in 2013, saying OCTG imports had been sold cheaply to the United States using government subsidies.
Refer to the input text as context and select the correct relationship between 'Vallourec' and 'pipe' from the available options.
Options: developer, product/material produced, member of, chief executive officer