LOS ANGELES — U.S. titanium shipments fell year on year in the third quarter of 2012, leaving the possibility of a third consecutive year of record shipments in doubt.

Net mill product shipments reached 10,600 tonnes (about 23.4 million pounds) in the third quarter, down 4.5 percent from 11,100 tonnes in the same year-ago period but up 5 percent from 10,100 tonnes in the second quarter of last year, according to data released this past week by the U.S. Geological Survey.

The USGS revised its second-quarter 2012 figures up from a previous 8,230 tonnes.

Forgings and extrusion billets accounted for 4,350 tonnes of the third-quarter total. The USGS no longer breaks out sheet and plate dispatches.

In 2011, full-year mill product shipments reached a record 45,500 tonnes, the second year in a row that a new high-water mark had been reached. With shipments through last year’s first three quarters running at an annualized rate of slightly less than 41,000 tonnes, a third consecutive record would depend on industry shipments rising in the fourth quarter.

Ingot production, which sometimes serves as a bellwether for mill product shipments, rose 7.9 percent to 17,800 tonnes in the third quarter compared with the second quarter.

Meanwhile, third-quarter scrap receipts were at 11,000 tonnes, down 3.5 percent from the same three-month span last year but up 1.9 percent from 10,800 tonnes in the second quarter. Purchased scrap accounted for 7,290 tonnes of that, and home scrap accounted for 3,690 tonnes.