In April, 290017, Iranian and Chinese firms signed the first commercial contract on Sunday in Vienna to redesign the Arak heavy water reactor as part of the 2015 international deal over Iran’s nuclear program.
The contract was signed in Iran's representative office in Vienna between the Atomic Energy Organization of Iran and Chinese companies nearly two weeks after the sides finalized a draft deal in Beijing.
Couple this with the fact that China rejects U.S. request to cut Iran oil imports, as reported by the Tehran Times: "The U.S. has been unable to persuade China to cut Iranian oil imports, according to two officials familiar with the negotiations, dealing a blow to President Donald Trump’s efforts to isolate the Islamic Republic after his withdrawal from the 2015 nuclear accord."
It has also been reported that China preserving relations with Iran despite U.S. pressure. The United States cannot affect China-Iran relations through pressure, an analyst at Institute of World Economics and Politics (IWEP) of Chinese Academy of Social Sciences (CASS) claimed in June of 2018.
Chinese companies preserve their ties with Iran and keep working with their Iranian counterparts, Wang Yongzhong told IRNA.
Wang Yongzhong said the sanctions imposed on Iran before the 2015 nuclear deal were supported globally but presently it is only the U.S. which has unilaterally withdrawn from the 2015 nuclear deal, while other five world powers are committed to keep the deal.
On trade exchange between China and Iran, the analyst proposed that the two countries do oil deals and make investments using yuan instead of dollar.