Frame longitudinal beam, frame assembly, vehicle and manufacturing process of frame longitudinal beam

The invention relates to a vehicle frame longitudinal beam, a vehicle frame assembly, a vehicle and a manufacturing process thereof.The vehicle frame longitudinal beam comprises a web, an upper wing plate and a lower wing plate, and the upper wing plate and the lower wing plate are fixed to the two opposite ends of the web in the first direction respectively; at least one of the upper wing plate and the lower wing plate comprises a first sub-wing plate and a second sub-wing plate which are arranged at intervals in the first direction, one end of the first sub-wing plate and one end of the second sub-wing plate are connected with each other, and the other end of the first sub-wing plate and the other end of the second sub-wing plate are connected with the web. The upper wing plate and/or the lower wing plate are/is formed by arranging the first sub-wing plates and the second sub-wing plates in the first direction at intervals, that is, the first sub-wing plates and the second sub-wing plates form the two-layer