Views: 0 Author: Site Editor Publish Time: 2025-11-24 Origin: Site
Stainless steel tubing, due to its superior comprehensive performance, has become an indispensable key material in modern automobile manufacturing. As the automotive industry develops towards lightweighting, high performance, long lifespan, and environmental friendliness, the application of stainless steel tubing is becoming increasingly widespread. Its main values are reflected in:
Safety and Structure: Providing high-strength and high-toughness structural support, enhancing collision safety.
Corrosion Resistance and Durability: Resisting corrosion from water, salt, chemicals, and exhaust gases, ensuring a long service life for components and reducing maintenance costs.
Heat and Pressure Resistance: Maintaining stable performance in harsh environments with high temperature and pressure (such as exhaust systems).
Lightweighting: Using thin-walled, high-strength steel tubing helps reduce the overall vehicle weight, thereby reducing fuel consumption and emissions.
Cleanliness and Environmental Protection: Ensuring the cleanliness of fuel, brake fluid, and other delivery systems, and being used in environmentally friendly exhaust gas treatment systems.
Stainless steel tubing is widely used in automobiles, mainly in the following three systems:
This is the earliest and most widely used application of stainless steel tubing. The exhaust system operates in a harsh environment (high temperature, high humidity, corrosive gases), requiring materials with extremely high heat and corrosion resistance.
Manifolds: Withstand the highest temperatures (up to 900°C), using austenitic stainless steel (such as 304, 321) or higher-grade heat-resistant stainless steel.
Front-end pipes and catalytic converter housings: Contact with high temperatures and contain corrosive catalysts, often using ferritic stainless steels such as 409L and 436L.
Mufflers and tailpipes: Exposed to the external environment, easily contacted with de-icing salts, etc., making them a major target for condensation corrosion; widely using 409L, 439, etc.
Collision components: Bumper impact beams, side door impact bars, etc., require extremely high strength and energy absorption, using high-strength ferritic stainless steel (such as 409L, 3CR12) or martensitic stainless steel.
Suspension Components: Suspension links and stabilizer bars in some models utilize the fatigue strength and corrosion resistance of stainless steel.
Body Frame and Reinforcement: High-strength stainless steel tubing is used as a reinforcing structure in critical areas to improve overall vehicle rigidity and safety.
Fuel Lines: Ensure clean and safe fuel delivery and prevent leaks. Austenitic stainless steel (304) is commonly used.
Brake Lines: Require extremely high safety, must withstand high pressure and be corrosion-resistant, and commonly use 304 stainless steel.
Hydraulically Formed Fittings: Used in complex structural components such as engine mounts and subframes, these parts are manufactured using a hydroforming process to achieve lightweight and high strength.
Steering Column and Driveshaft: Used in some high-performance or commercial vehicles.
Decorative Parts: Such as exhaust tailpipes, often using high-gloss 304 stainless steel or even surface polishing for aesthetic purposes.
Hydrogen Fuel Cell Vehicles (FCEVs): Hydrogen storage pipes and pipelines used to transport high-pressure hydrogen, requiring extremely high strength and resistance to hydrogen embrittlement.
Battery Packs: Serving as structural supports for battery modules or cooling pipelines for the battery pack.
| Type | Main Grades | Characteristics | Main Applications |
| Ferritic stainless steel | 409L, 439, 436L | It has low cost, good resistance to chloride stress corrosion cracking, low coefficient of thermal expansion, and good thermal conductivity. However, its formability and high-temperature resistance are not as good as austenitic materials. | Exhaust system (muffler, tailpipe), anti-collision structural components |
| Austenitic stainless steel | 304, 304L, 321, 316L | Excellent overall performance: high corrosion resistance, excellent formability and toughness, and resistance to high-temperature oxidation. Strength can be improved through work hardening. Relatively high cost. | Exhaust manifold, fuel line, brake line, decorative tailpipe，Car air conditioning system condenser |
| Martensitic stainless steel | 420, 17-4PH | It can achieve extremely high strength and hardness through heat treatment, but its weldability and corrosion resistance are relatively poor. | High-strength structural components, such as crash bars and drive shafts |
| duplex stainless steel | S32205 | It combines the advantages of both austenitic and ferritic materials: high strength and good corrosion resistance (especially resistance to pitting and stress corrosion). However, it is costly. | Structural components designed for harsh environments, such as chassis components for commercial vehicles. |
Excellent Corrosion Resistance: Extends component lifespan, especially suitable for chassis and exhaust systems.
High Strength and Lightweight: Allows for thinner pipe walls, reducing weight while ensuring safety.
Excellent High-Temperature Performance: Ensures long-term stable operation of the exhaust system at high temperatures.
Good Machinability and Formability: Suitable for complex manufacturing processes such as bending, welding, and hydroforming.
Safe and Reliable: Provides a clean, pressure-resistant passage for critical safety systems (braking, fuel).
Environmentally Friendly and Recyclable: 100% recyclable, aligning with green manufacturing principles.
The production of automotive stainless steel pipes typically involves the following key steps:
Pipe Fabrication: Stainless steel strips are rolled and welded into straight-seam welded pipes using high-frequency welding (HFW).
Cold drawing/cold rolling: Cold working reduces diameter and wall thickness, improves dimensional accuracy and surface finish, and significantly enhances material strength and hardness.
Heat treatment (annealing): Eliminates internal stresses generated during cold working, restoring the material's plasticity and toughness.
Finishing and cutting: Straightening, polishing, and cutting to specified lengths.
Bending and forming: Using CNC bending machines to bend the tube into complex shapes required by the design.
Hydraulic forming: For complex structural components, the tube is placed in a mold, and high-pressure liquid inside expands it to fit the mold cavity, forming the final three-dimensional shape.
Higher strength: Developing new types of stainless steel with lower cost and higher strength to further achieve lightweighting.
New energy vehicle drive: Demand for high-performance stainless steel tubes will surge in the fields of Type IV hydrogen storage tank liners (barrier layer with all-plastic liner) and Type III tanks (all-metal liner) for FCEVs.
Smart manufacturing: Employing advanced technologies such as laser welding and online quality monitoring to improve production efficiency and product quality consistency.
Customized Materials: Developing customized, specialized stainless steel materials for different application scenarios (such as high-temperature resistance and hydrogen embrittlement resistance).
Stricter Environmental Regulations: Driving the use of more corrosion-resistant, long-life materials in exhaust systems to reduce emissions and maintenance throughout the vehicle's lifecycle.
