Description
【 BMW Original Factory Specification 】 Front suspension upper control arm assembly
Core parameters
Original factory accessory number: 31126775967
Compatible vehicle models: 2008-2015 BMW 730 (F02/F04 chassis)
Core materials: German imported ductile iron main body + high-pressure forged aluminum alloy connecting parts + special polyurethane buffer rubber sleeve
Process standard: CNC precision machining with ±0.01mm tolerance, TUV certified 100,000 fatigue tests
I. Detailed Explanation of Materials and Craftsmanship
Main structure
Arm body: Ductile iron (QT450-10
The tensile strength is ≥450MPa, 20% lighter than ordinary cast iron, and the toughness is increased by 35%
Ball joint pin: chromium-molybdenum alloy steel (42CrMo)
The surface is treated with high-frequency quenching, with a hardness of HRC58-62 and a wear resistance life exceeding 80,000 kilometers
Bushing: Hollow hydraulic bushing + polyurethane outer covering layer
The double-layer damping design filters out minor vibrations while maintaining a clear road feel
Special processes
3D forging forming: Aluminum alloy components are forged in multiple directions to eliminate internal bubbles
Salt bath nitriding treatment: Anti-corrosion layer on the surface of the ball head pin, resistant to the erosion of de-icing agents
Low-temperature assembly process: Cold assembly of ball heads at -196℃ in liquid nitrogen to prevent thermal deformation
Ii. Functional Features
✅ Precise control restoration: Original factory data positioning hole position, eliminating steering wheel play and deviation
✅ Global shock absorption and enhancement: Hydraulic bushings effectively filter out low-frequency vibrations below 30Hz (performs better on rough roads)
✅ Safety enhancement design: The ball head pin innovatively adopts a double slot structure to eliminate the risk of running out
✅ Long-term durability guarantee: The ozone aging resistance grade of the polyurethane rubber sleeve meets the GJB150A standard
