The first Volvo truck assembled in the United States last week rolled out of the Volvo White trucking plant in Dublin, Va., as about 700 people, including Volvo Truck Corp. president Sten Langenius, gathered outside the plant to celebrate.

Langenius, who flew in for the ceremonies from the company's headquarters in Sweden, said assembly of heavy duty Volvo trucks in the United States was an indication of the firm's long-term commitment in this country. olvo's truck sales in 1981 totaled $1.5 billion and profits were $130 million, Langenius said. AB Volvo, the parent company, had sales of $8.8 billion and ranks 67th in size among industries worldwide.

The Dublin plant employs about 650 people and is producing 20 trucks a day, well below its capacity of 50. The plant has been operating at 40 percent capacity because economic conditions have slowed truck sales.

Langenius, at a news conference, said, "In these difficult economic times, everyone seems to be wondering which manufacturers will be here tomorrow. I hope you see Volvo's potential as an American truck maker. . . .The U.S. assembly of Volvo trucks is a part of Volvo's commitment to assured growth and long-term success."

Volvo bought White Motor Co. and formed Volvo White Truck Corp. in September 1981. Since then, Volvo White has been producing exclusively White-model trucks in this country.

Volvo trucks were first sold in the United States in 1975.

In addition to trucks, AB Volvo's business activities include cars, food, energy and manufacturing systems. In 1981, the company's sales in the United States were $2 billion.