Metal Tubes for Automotive Engines

Metal Tubes for Automotive Engines

Metal tubular components for oil, coolant and pneumatic circuits in automotive engines

Motorbacs has more than 16 years of development and manufacturing experience in engine metal tube assemblies, with an annual production capacity exceeding 10 million units. With deep technical expertise and engineering accumulation, we work closely with customers from the early design stage, participating in layout planning and cost optimization, and providing feasible design solutions that meet installation space constraints and performance requirements.

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Production Process
Production Process
  • Material preparation
  • Tube bending
  • Tube end forming
  • Welding & fixing
  • Brazing
  • Electroplating
  • Reshaping
  • Leak testing
  • Packaging
Features
Product Type Material Welding Method Welding Strength Airtightness Neutral Salt Spray Test
Engine Coolant Tubes Stainless steel Brazing ≥ 350 N/mm² or greater than base material strength 0.5–0.8 MPa no leakage, or leakage rate ＜ 0.2 ml/min under 0.5 MPa pressure Chromate coating – 500 hours no red rust
Carbon steel + Surface treatment Brazing ≥ 350 N/mm² or greater than base material strength 0.5–0.8 MPa no leakage, or leakage rate ＜ 0.2 ml/min under 0.5 MPa pressure 1000 hours no red rust
Engine Oil Tubes Stainless steel Brazing ≥ 350 N/mm² or greater than base material strength 0.5–0.8 MPa no leakage, or leakage rate ＜ 0.2 ml/min under 0.5 MPa pressure Chromate coating – 500 hours no red rust
Carbon steel + Surface treatment Brazing ≥ 350 N/mm² or greater than base material strength 0.5–0.8 MPa no leakage, or leakage rate ＜ 0.2 ml/min under 0.5 MPa pressure 1000 hours no red rust
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Automotive Chassis Parts

Hydroformed subframe tubes help reduce vehicle weight by forming the structure as a single piece, which cuts down the number of parts and weld points. Variable cross-section hydroforming allows tube diameter and wall thickness to be optimized where loads are higher, achieving more than 20% weight reduction while maintaining strength and stiffness. As a result, vehicle energy consumption and emissions are reduced, while chassis performance remains unchanged.

After forming, high-strength steel tubes are usually protected with electrophoretic coating. Zinc phosphating is often applied as well, helping the coating bond better to the surface. For applications that require corrosion protection, hot-dip galvanizing can also be used to provide long-lasting durability.

Hydroformed frame components significantly reduce fatigue stress by cutting the number of weld joints by more than 60%, which helps avoid stress concentration at critical points. Shot peening is then applied to strengthen the material surface and improve fatigue resistance. With the extra stiffness gained from hydroforming, the structure handles repeated loads more easily, which helps extend fatigue life by around 25–30% and keeps the frame reliable even when working under heavy loads or on rough terrain.