Project Description
Introduction
Automotive tailgate support steel tubes serve as the structural and functional backbone of modern rear-door, liftgate, and cargo-access systems. Whether integrated into power-operated struts, manual support rods, or heavy-duty hinge assemblies, these tubes must withstand repeated cyclic loading, resist bending under dynamic payload conditions, and maintain precise dimensional stability throughout the vehicle's service life.
At Fushun Steel Tube, we manufacture seamless and cold-drawn carbon steel tubes specifically engineered for tailgate support applications, delivering exceptional concentricity, straightness, and surface consistency. Our product range covers low-to-high carbon steel grades, allowing OEM engineers and tier-one suppliers to precisely match material strength, formability, and fatigue resistance to specific vehicle architectures.
Produced through controlled hot piercing, multi-pass cold drawing, and customizable heat treatment, our tubes eliminate weld-seam vulnerabilities and provide reliable performance in demanding automotive environments. Tell us your dimensional and performance requirements, and our engineering team will recommend the optimal grade and processing route.
Structural Integrity & Engineering Design
The seamless manufacturing route guarantees uniform radial stress distribution and eliminates the fatigue-initiation points commonly associated with welded seams. By combining metallurgical consistency, tight tolerance control, and flexible manufacturing, we help you reduce assembly complexity and extend component longevity. Our integrated production workflow ensures that every tube meets strict geometric tolerances before reaching your assembly floor.
Applications
Our tailgate support tubes are engineered for direct integration into specific automotive and commercial vehicle components:
- Power liftgate strut outer cylinders and inner piston sleeves
- Manual tailgate gas spring housings and damping tubes
- Drop-down tailgate hinge pivot tubes and torque sleeves
- Split-fold rear door support rods and linkage tubes
- Commercial van cargo door stay tubes and locking actuator housings
- Pickup truck bed extender support tubes and tailgate assist cylinders
- RV and specialty vehicle rear access door structural sleeves
- Off-road and agricultural utility vehicle tailgate reinforcement tubes
For highly corrosive environments or extreme thermal cycling, we also manufacture compatible support housings using our stainless steel tube and boiler tube production lines.
Specifications & Standards
The carbon steel grades in our tailgate support tube portfolio are manufactured and certified according to globally recognized mechanical tubing standards. We focus exclusively on seamless and precision cold-drawn products:
- ASTM / SAE: ASTM A519 Seamless Carbon & Alloy Steel Mechanical Tubing, SAE J524 / J525
- EN / DIN: EN 10305-1, EN 10305-4 Seamless Cold-Drawn Tubes for Hydraulic & Pneumatic Systems, DIN 2391 Precision Seamless Steel Tubes
- ISO: ISO 3304, ISO 10763 (Hydraulic & Pneumatic Cylinder Tubes)
- JIS: JIS G3445 Carbon Steel Tubes for Machine Structural Purposes
- GB: GB/T 3639 (Cold-Drawn or Cold-Rolled Precision Seamless Steel Tubes)
While ASTM A36 / EN S235 are commonly referenced for structural carbon steel, tube production follows mechanical tubing standards (A519/EN 10305) with chemically equivalent low-carbon compositions optimized for cold drawing and forming. All grade cross-references are verified during order confirmation.
Available Sizes & Delivery
Fushun Steel Tube provides scalable manufacturing tailored to automotive prototyping, pilot runs, and high-volume production:
| Tube Type | Outer Diameter (OD) | Wall Thickness (WT) | Length / Tolerance |
|---|---|---|---|
| Hot-Rolled Seamless | 20 – 180 mm | 2.0 – 15 mm | 3 – 12 m |
| Cold-Drawn / Cold-Rolled | 10 – 120 mm | 1.0 – 10 mm | ISO h8/h9 (OD), H8/H9 (ID) |
| Honed / SRB Tubes | ID 16 – 100 mm | Custom | Ra ≤ 0.4 μm |
- Ready Stock
- Standard dimensions in SAE 1020/1045 and EN C20E/C45E are available for immediate dispatch. Lead time: ~7 days.
- Custom / Non-Standard Sizes
- MOQ starts at 2–3 metric tons. Production lead time: 25–35 days.
- Small-Batch Trials
- Accepted for prototype validation and engineering testing.
- Volume Contracts
- Tiered pricing and prioritized scheduling for annual OEM programs. Delivery windows are fully negotiable.
Chemical Composition
| Grade (SAE) | Equivalent (EN) | C | Mn | P (≤) | S (≤) | Si |
|---|---|---|---|---|---|---|
| 1010 | C10E / 1.1121 | 0.08–0.13 | 0.30–0.60 | 0.030 | 0.035 | 0.10–0.30 |
| 1020 | C20E / 1.1151 | 0.18–0.23 | 0.30–0.60 | 0.030 | 0.035 | 0.10–0.30 |
| 1035 | C35E / 1.1181 | 0.32–0.38 | 0.50–0.80 | 0.030 | 0.035 | 0.15–0.35 |
| 1045 | C45E / 1.1191 | 0.43–0.50 | 0.60–0.90 | 0.030 | 0.035 | 0.15–0.35 |
| 1060 | C60E / 1.1221 | 0.55–0.65 | 0.60–0.90 | 0.030 | 0.035 | 0.15–0.35 |
Compositional ranges comply with standard SAE and EN specifications for cold-drawn mechanical tubing. Mn and Si levels may be fine-tuned within standard limits to optimize cold-drawing response or hardenability, subject to engineering approval.
Manufacturing Process
Smelting Route: All billets are produced via EAF + LF + VD to ensure low dissolved gases, controlled non-metallic inclusions, and homogeneous chemistry. For high-cycle fatigue applications or premium liftgate programs, we offer ESR or VIM+VAR routes upon request.
Tube Manufacturing: Production begins with hot seamless piercing, followed by rotary rolling and sizing. Mother tubes undergo spheroidize annealing, pickling, and multi-pass cold rolling or cold drawing to achieve target dimensions and mechanical properties. Subsequent stress-relief or normalization heat treatment stabilizes the microstructure, followed by precision straightening and cutting.
For hydraulic strut applications, internal honing or skiving & roller burnishing (SRB) is applied. Every processing parameter is adjustable; our metallurgical team will collaborate with you to select the most cost-effective and performance-optimized route.
Mechanical Properties
| Grade | Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) ≥ | Hardness (HBW) |
|---|---|---|---|---|---|
| 1010 / C10E | Cold Drawn (BK) | ≥ 380 | ≥ 280 | 10 | ≤ 130 |
| 1010 / C10E | Normalized (NBK) | 310–410 | ≥ 185 | 25 | ≤ 120 |
| 1020 / C20E | Cold Drawn (BK) | ≥ 420 | ≥ 320 | 10 | ≤ 150 |
| 1020 / C20E | Normalized (NBK) | 350–450 | ≥ 215 | 22 | ≤ 140 |
| 1045 / C45E | Cold Drawn (BK) | ≥ 580 | ≥ 450 | 8 | ≤ 190 |
| 1045 / C45E | Normalized (NBK) | 500–650 | ≥ 305 | 16 | ≤ 180 |
| 1045 / C45E | Quenched & Tempered | 650–850 | ≥ 430 | 14 | 190–230 |
| 1060 / C60E | Quenched & Tempered | 750–950 | ≥ 500 | 12 | 210–260 |
Data represents longitudinal test specimens. Properties for thicker sections or transverse orientations follow standard derating allowances. Custom mechanical targets are achievable through adjusted cold-work reduction ratios and tailored thermal cycles.
Heat Treatment
| Treatment Type | Temperature Range (°C) | Soaking Time | Cooling Method | Application / Notes |
|---|---|---|---|---|
| Spheroidize Annealing | 680–720 | 2–4 hrs | Furnace cool to ≤ 500°C | Softens medium/high-carbon grades for severe cold forming or drawing |
| Normalizing | 850–900 | 1 hr per 25 mm WT | Still air | Refines grain structure, restores ductility and dimensional stability |
| Stress Relieving | 550–650 | 1–2 hrs | Air or furnace cool | Removes cold-work residual stresses; prevents distortion during machining |
| Quenching | 820–860 | 30–60 min | Oil or water quench | Applied to 1045/1060 for high strength; requires immediate tempering |
| Tempering | 450–650 | 1–2 hrs | Air cool | Balances final hardness and toughness after quenching |
All heat treatments for precision tubes are conducted in controlled-atmosphere or protective-gas furnaces to prevent surface decarburization and scaling. Induction hardening of specific zones (e.g., pivot points or sealing surfaces) is available upon request.
Surface Finish & Tolerances
Fushun Steel Tube delivers tailgate support tubes with surface conditions optimized for downstream assembly and environmental exposure:
- Hot-Rolled Seamless: Available as-rolled or pickled. Suitable for structural hinge sleeves or non-sealing support members.
- Cold-Drawn Precision: Bright finish with tight dimensional control. Standard tolerances: OD ±0.05–0.10 mm (ISO h8/h9), WT ±5–7%. Ideal for strut housings and pivot tubes requiring consistent clearance.
- Honed / SRB Tubes: Internal surface roughness Ra ≤ 0.4 μm, with options down to Ra ≤ 0.2 μm for gas spring and hydraulic liftgate cylinders. ID tolerance typically H8/H9.
- External Machining: OD turning or centerless grinding available, achieving h7/h6 tolerances and Ra ≤ 0.8 μm for press-fit brackets or threaded interfaces.
All finishing operations are performed in-house to guarantee traceability and prevent transit-induced surface damage.
Quality Assurance & Testing
Quality control is integrated into every production phase. Fushun Steel Tube operates under an ISO 9001 certified system, with inspection protocols aligned to global automotive tubing requirements:
- Raw Material Verification: OES chemical analysis, inclusion rating, and macrostructure evaluation.
- In-Process Control: Laser diameter monitoring, ultrasonic wall-thickness measurement, and straightness verification after each drawing pass.
- Non-Destructive Testing (NDT): Ultrasonic (UT) and Eddy Current (ET) testing for longitudinal/transverse flaws; Magnetic Particle (MT) inspection for tube ends.
- Hydrostatic Test: Pressure validation to confirm structural integrity and leak-tightness.
- Mechanical & Metallographic: Tensile, yield, elongation, hardness, Charpy impact (if specified), grain size, and microstructure analysis.
- Certification & Third-Party: Every shipment includes an EN 10204 3.1 Mill Test Certificate. EN 10204 3.2 certification with independent witness testing is available. We welcome SGS, TÜV, or BV inspections.
Packing & Shipping
Protective packaging ensures dimensional accuracy and surface quality are preserved during global transit. Hot-rolled or pickled tubes are coated with anti-rust oil, bundled with high-tensile steel straps, and fitted with reinforced plastic end caps. Precision bright or honed tubes are individually capped, wrapped in VCI anti-corrosion film or protective paper, and secured in reinforced wooden crates or steel frames to prevent bending and abrasion.
We support ocean freight, air cargo, and cross-border land transport. Custom labeling, barcode tracking, and project-specific shipping marks are available. All wood packaging complies with ISPM 15 export standards.
Frequently Asked Questions
- Can you produce tailgate support tubes in non-standard OD/WT combinations?
- Yes. Our cold-drawing lines accommodate custom dimensions. MOQ is typically 2–3 tons, with a detailed tolerance and tooling feasibility report provided before production.
- Which grade is best for power liftgate struts versus manual support rods?
- For power liftgate cylinders, SAE 1020/C20E offers ideal formability and bore finish. Heavy-duty manual rods benefit from Q+T SAE 1045/C45E for superior strength and wear resistance.
- Do you supply tubes pre-treated for corrosion resistance?
- We supply mill, pickled, or bright finishes ready for your galvanizing or coating processes. Temporary VCI rust prevention or phosphate coating is available for transit protection.
- How do you control straightness and ovality for long support tubes?
- Multi-pass cold drawing and precision roller straightening ensure ovality within 0.5% of OD and straightness ≤ 1.0 mm/m. Additional laser profiling is available for tight clearances.
- What is the lead time, and do you support low-volume prototype orders?
- Stocked sizes ship within ~7 days. Custom runs require 25–35 days. We support prototype validation with small-batch trials before scaling to volume production.
Contact our technical sales team to discuss your project requirements and receive a tailored quotation.
