Dongfeng VL truck parts Welding assembly of right connecting beam of frame 8405370-C4100

Built to withstand the static and dynamic forces of frame connection (e.g., cargo weight transfer, road impact), the connecting beam’s base material uses Q355ND low-alloy high-strength steel—specifically designed for low-temperature and heavy-duty applications. This steel delivers a minimum yield strength of 355 MPa, tensile strength of 470–630 MPa, and impact toughness of ≥34 J at -40°C, enabling the assembly to bear a maximum static load of 35kN without deformation. Critical weld joints are formed via robotized MIG welding (metal inert gas welding) with a weld bead size of 8mm×5mm, ensuring 100% penetration and weld strength ≥90% of the base material. Each weld undergoes ultrasonic flaw detection (UT) to eliminate internal defects (e.g., porosity, cracks), meeting ISO 15614-1 welding standards. Compared to manual-welded assemblies, this robotized process reduces weld failure risk by 70% under frequent load cycles

Engineered to minimize stress concentration and improve torsional stiffness, the connecting beam features a box-type closed cross-section (180mm×80mm×6mm wall thickness) that distributes vertical and lateral forces evenly across the main frame rail. It integrates 6mm-thick reinforcing plates at suspension mounting points—spreading localized loads (from suspension actuation) over a 150mm-wide area and reducing stress by 40%. The beam’s ends are beveled at 30° to ensure tight fitting with the main frame rail and auxiliary beam, minimizing gap-induced stress (≤50 MPa at joint areas). Unlike open-channel connecting beams that lack structural support, this optimized design enhances the VL’s frame torsional stiffness by 35%, maintaining frame alignment even when the truck operates on uneven terrain (e.g., construction sites, unpaved roads)

Designed to resist corrosion from road salt, mud, and moisture (common in undercarriage environments), the assembly undergoes a five-stage protective process. First, a chemical degreasing and derusting treatment removes surface contaminants. Next, a zinc phosphate conversion coating (60μm thickness) creates a porous base for coating adhesion. Then, an electrophoretic primer (80μm) forms a uniform moisture barrier, preventing rust from forming on steel surfaces. A high-build epoxy mid-coat (70μm) fills minor surface defects, followed by a UV-stabilized polyurethane topcoat (50μm) that resists chipping, chemical damage (e.g., diesel, road deicers), and UV degradation. This coating system passes 1,500 hours of neutral salt spray testing without rust or peeling, ensuring durability in snowy, coastal, or mining regions—where undercarriage corrosion is a major threat to frame integrity

Designed for efficient replacement by fleet technicians, the assembly simplifies installation with user-friendly details. All mounting holes are drilled to H8 tolerance (ensuring perfect alignment with the VL’s M22 frame bolts) and chamfered to avoid damaging bolt threads during assembly. The weld joints are ground smooth to eliminate sharp edges that could damage adjacent components (e.g., brake lines, wiring harnesses). The package includes 8 grade 10.9 high-tensile frame bolts (M22×70mm) and lock washers, pre-lubricated with molybdenum disulfide to prevent thread galling in high-temperature environments. Installation takes 60–80 minutes: remove the old assembly by detaching the frame bolts, align the new assembly’s reference marks with the main and auxiliary frames, torque the bolts to 320 N·m (per OEM specifications), and verify frame movement. Each unit undergoes dimensional inspection via CMM (Coordinate Measuring Machine), load-bearing testing, and weld quality checks, backed by a 24-month warranty against defects (e.g., weld cracking, coating peeling, dimensional inaccuracies)