LORDSTOWN, Ohio (AP) _ The United Auto Workers today struck a General Motors Corp. fabricating plant that produces parts for 14 GM models including the fast-selling Saturn. Saturn production will shut down Friday as a result, the company said.

Both union and managmement said they were willing to continue talks on grievances that focused on job security and health and safety issues.

Bob Jones, a company spokesman at the plant, said union members had left the fabricating plant and set up picket lines.

The adjacent GM assembly plant was still operating as the pickets went up, Jones said. The next shift change at the plant would be midafternoon.

At the Saturn plant in Spring Hill, Tenn., officials said production of the popular cars would halt at 3 a.m. Friday because of the cutoff of parts from Ohio. ''We will be shutting down after the end of the second shift,'' said Saturn spokesman Bill Betts.

Saturn doesn't typically stockpile parts, keeping only enough on hand to build already scheduled cars. More than 1,000 Saturns are built each day.

David Garrity, an analyst in New York for McDonald & Co. Securities Inc., said Wednesday that the hot-selling Saturn is the best thing GM has going. There was a 13-day supply of Saturns nationwide, compared with a 61-day supply for all GM cars.

''Saturn does not make or break GM, but halting production there will hurt the company a bit,'' said Michael Bowyer, an industry analyst with Duff & Phelps in Chicago.

In Lordstown, Local 1714 Trustee Chip Hunsicker said job security at the plant was a key sticking point. The union represents 2,400 workers at the fabricating plant.

Negotiations reportedly have involved the proposed elimination of some 240 jobs in the die-making operations. GM wants to consolidate these jobs at other GM plants by the end of the year.

GM, which lost about $8 billion in North American car and truck sales last year, has said it will trim 74,000 jobs by 1995.