The under the MOU the Chinese firms have agreed they will use domestic providers in their US projects "wherever feasible". The union said the agreement is its first with a Chinese company.
The parties said they expect 50,000 tons of US steel to build the towers of a 600MW west Texas wind farm being developed by US Renewable Energy Group and Cielo Wind Power, using A-Power turbines.
The wind farm came under fire from senators led by Charles Schumer of New York, who argued that federal stimulus dollars should not fund overseas companies. Additionally, A-Power is developing a turbine assembly plant in Nevada.
A United Steelworkers spokesman said that in contrast to some press reports, the MOU does not guarantee components will be made with American steel.
"Right now these turbines could be produced with about 60% domestic content," the spokesman said. "We hope in time that the number will grow close to 100%."
He added: "It will take time for the domestic supply chain to grow. On the shorter term it might not be feasible to have some components domestically sourced."