In the context of the input sentence, determine the relationship between 'Tenaris' and 'steel'.
Options: operator, creator, product/material produced, legal form

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.
product/material produced