Dongfeng Xinjiang truck parts flat frame Right step beam welding assembly 8405370-KXGG02Y

Crafted from Q345B low-alloy high-strength steel—a premium material for truck frame components—the step beam delivers exceptional load-bearing capacity tailored to frequent driver boarding and occasional heavy use (e.g., carrying tools). This steel exhibits a minimum yield strength of 345 MPa, tensile strength of 470–630 MPa, and impact toughness of 34 J at -40°C (critical for Xinjiang’s frigid winters). The beam’s main body features a box-type cross-section (80mm×50mm, 4mm wall thickness) that enhances bending resistance by 50% compared to open-channel designs, enabling it to withstand a static load of up to 800 kg (exceeding the design requirement of 500 kg for commercial truck steps). After shot blasting (SA 2.5 grade) to remove surface impurities, the steel undergoes stress relief annealing at 600°C—eliminating welding-induced internal stress and preventing crack formation under cyclic loads (e.g., daily boarding)

The assembly’s critical joints (step plate to main beam, mounting brackets to frame interface) are welded using the MIG (Metal Inert Gas) welding process—an industry standard for high-strength truck components—with a weld leg height of 6mm (meeting AWS D1.1 welding codes). Each weld undergoes 100% visual inspection (VT) and ultrasonic testing (UT) to detect defects like porosity or incomplete fusion, ensuring a weld strength of ≥320 MPa (matching the base material’s strength). The step plate (5mm-thick Q345B steel) is welded to the main beam with a continuous fillet weld (no spot welds), preventing water or debris from accumulating in gaps and reducing corrosion risks. Additionally, the mounting brackets are welded at a 90° angle to the main beam (tolerance ±0.5°), ensuring the step remains level even after years of use—avoiding tripping hazards for drivers

Designed to resist corrosion from Xinjiang’s harsh environments (road salt in winter, dust and moisture in summer), the step beam undergoes a three-stage protective coating process:

Zinc Phosphate Coating (50μm): Forms a crystalline base layer that improves adhesion of subsequent coatings and provides initial corrosion resistance against salt spray.

Electrophoretic Primer (70μm): Seals micro-pores in the steel surface, blocking moisture intrusion and electrochemical corrosion—critical for flat frame trucks exposed to road debris.

Polyester Powder Coating (80μm): Baked at 180–200°C to form a hard, scratch-resistant finish (Mohs hardness ≥5H) that resists chipping, diesel stains, and UV degradation (passing 1,500 hours of xenon lamp aging with no color fade).

This coating system ensures the step beam remains rust-free for 5+ years, even in Xinjiang’s extreme climates—from -35°C winter nights to 45°C summer days

The step beam integrates user-friendly features to enhance safety and simplify maintenance, addressing the practical needs of truck drivers and fleet technicians:

Anti-Slip Step Surface: The step plate is punched with 12mm-diameter anti-slip holes (spaced 30mm apart) that provide secure traction even in wet or icy conditions—reducing fall risks by 70% compared to smooth surfaces.

Drainage Channels: Two 10mm-wide drainage channels along the step’s edges direct rainwater or melting snow away from the beam, preventing water accumulation and freeze-thaw damage in winter.

Easy Installation: The package includes 4 grade 8.8 high-strength bolts (M12×40mm) and lock nuts (pre-lubricated with anti-seize compound), requiring only a 19mm socket for installation—no specialized tools needed.

Installation takes 30–40 minutes: clean the frame’s mounting surface, align the step beam’s holes with the frame, torque the bolts to 85 N·m (per Dongfeng’s specs), and verify step stability. Each unit undergoes load testing (800 kg static load for 24 hours), dimensional inspection via CMM, and coating adhesion checks, backed by a 36-month warranty against defects (e.g., weld cracking, coating peeling, structural deformation)