Rick Santorum said Sunday that he has the best record on entitlement reform of any of the Republican presidential candidates racing to take on President Obama in 2012.

"There's nobody that can touch my record," Santorum told "Fox News Sunday."

Describing his concern of being "pigeonholed as a candidate" because of his position on social issues, Santorum said he also has the record on the cultural and foreign policy matters.

But it's his two terms in the Senate that he credits for making him a contender with a substantive background and national appeal.

"That's the real difference between me and everybody else in this race, is accomplishment, in a tough environment. And to get conservative things accomplished," he said.

Santorum served as a U.S. senator from Pennsylvania from 1995-2007, and won reelection in 2000 even though George W. Bush didn't carry the state. During his time in office, he worked on welfare reform, a central tenet of the Republican "Contract With America" that resulted in one of the largest overhauls of the welfare system. 

"I went toe to toe with Daniel Patrick Moynihan, Ted Kennedy, the lions of the left, who were going to defend that system. Bill Clinton, who did not want to end the federal entitlement to welfare. He vetoed it twice. But we continued to work on it and were able to end the federal entitlement, require work and put time limits on welfare," he said.

Santorum, who placed fifth in the Iowa straw poll, said that creating time limits on Medicaid payments will be required to keep that program intact. He warned that unless the U.S. reforms entitlements, the size and scale of government will end up eating up 40 to 50 percent of the overall economy.

"That's the big problem," he said, adding that he would also repeal President Obama's health care law. 

Santorum also proposed returning the manufacturing base to the United States by reducing corporate tax rates to zero for companies that produce in the U.S. To attract manufacturers to return from abroad also means drilling for natural gas in the U.S. because manufacturers rely heavily on that supply for their energy needs.

"One of the big impediments to manufacturing here is our tax -- our tax system doesn't match up with other tax systems around the world. As a result, it's harder to export here," he said. "We need to do that in other areas to do two things. No. 1, create jobs in the energy sector, but No. 2, to create a stability for the manufacturing sector. The fact that we now have stable gas prices and probably will for quite some time is a great incentive for manufacturers to come back, because they are one of the heaviest users of natural gas."

Santorum praised the economy "boomlet" in Pennsylvania as a result of drilling for Marcellus Shale in the state. However, several environmental groups have warned about hydraulic fracturing, also known as "fracking," the process for obtaining the natural gas, which requires enormous amounts of water and chemicals to force open cracks below the earth to create space where gas can be extracted from subterranean rock beds.