A Chinese national was sentenced Wednesday to nine years in federal prison for his role in smuggling US-manufactured goods used to enrich uranium into Iran, in a case that is connected to recent diplomacy deal with that country.

Sihai Cheng, 36, who was raised in a rural village in China, grew tearful as he pleaded to US District Judge Patti B. ­Saris for mercy, in an hourlong ramble that touched upon his upbringing in a poor family, and his desire to broker the smuggling deal to earn money to support his parents and siblings.

“It was never about getting rich,’’ Cheng said. “It was about survival.’’

Saris refused to categorize Cheng’s crimes as acts of terrorism, a designation requested by the government that could have tripled his sentence. But Saris still sentenced Cheng to a longer term than recommended under sentencing guidelines, which called for a four and a half-year sentence.

“This isn’t about the security interests of the United States; it was about the security of the world,’’ Saris said before sentencing Cheng.

Cheng was indicted in 2013 along with an Iranian national and two Iranian companies for smuggling US-manufactured pressure transducers through China and into Iran, to help that country in its efforts to produce weapons-quality uranium. The Iranian national, Seyed Abolfazl Shahab Jamili, lives in Iran, and a warrant had been issued by the United States for his arrest. But charges against him were dismissed earlier this month when the United States and Iran agreed to a program that allowed for the release or dismissal of charges for 14 Iranian nationals accused of US crimes.

David Albright, a researcher with the Institute for Science and International Security, who has studied Iran’s proliferation efforts, testified during a hearing Wednesday that the transducers are used in gas centrifuges to enrich uranium. Because international sanctions prohibit transporting transducers into Iran, the country depended on illegal networks like Cheng’s to build its nuclear facilities, Albright testified.

“They were critical parts to make a centrifuge work, and if Iran did not get these parts they could not use a centrifuge,’’ Albright testified.

The transducers were manufactured by the Andover-based MKS Instruments,which was not targeted in the investigation. The parts were smuggled through the company’s Shanghai offices and into Iran, where they were eventually taken to the Kalaye Electric Company, an arm of the Iranian government that worked to produce nuclear weapons.

Cheng was involved in smuggling 1,185 transducers between 2009 and 2011, and received $1.8 million, Assistant US Attorney Stephanie Siegmann said.

Cheng’s lawyer, Stephen Weymouth, accused federal prosecutors of unfair treatment against Cheng — whom he described as a middleman in the smuggling scheme —while agreeing to dismiss charges against Jamili, who he called the mastermind. Jamili had a national interest to obtain the parts, Weymouth argued.

Earlier this month, US officials said none of the Iranians involved in the prisoner release agreement had been involved in terrorism.

“If Mr. Jamili is not a terrorist, Mr. Cheng is not a terrorist. The government can’t have it both ways,’’ Weymouth argued.

Saris said she could not judge Jamili’s release without knowing the details, though she called him an equal accomplice in Cheng’s crimes. Still, she agreed to dismiss the case against him at the government’s request and said Cheng’s sentence will serve as a deterrent against smuggling.

“I hope this is sending a clear message that regardless of the current diplomatic stance in all this, it’s still against the law to sell these products to Iran,’’ she said.

Milton J. Valencia can be reached at mvalencia@ globe.com. Follow him on Twitter @miltonvalencia.