Thin Wall Longitudinal Welded Steel Pipe

Zhongtian Thin Wall Longitudinal Welded Steel Pipe is a lightweight steel pipe made from strip steel or steel plate as the base material, rolled and then welded along a single longitudinal weld.

- Wall thickness: 1.0–6 mm

- Outer diameter: Φ20–Φ610 mm (common specifications Φ33–Φ426 mm)

- Standard length: 6 meters, 12 meters, custom lengths also available

- Core process: High-frequency resistance welding (ERW/HFW)

- Standards: GB/T 3091-2025, GB/T 13793-2016, ASTM A53

Common materials and mechanical properties

Thin Wall Longitudinal Welded Steel Pipe is made of high-quality carbon steel, balancing structural strength and processing performance:

1 Q195: Yield strength ≥ 195 MPa, suitable for scaffolding, guardrails, and low-pressure water pipelines

2 Q215A/B: Yield strength ≥ 215 MPa, mainly used for fluid transportation and general structural pipes

3 Q235B: Yield strength ≥ 235 MPa MPa, the most versatile, widely used in construction, water supply and drainage, and gas transmission applications.

4 Q355B: Yield strength ≥ 355 MPa, suitable for load-bearing structures and mechanical equipment manufacturing.

Production Process

As a professional manufacturer, Zhongtian adopts a fully automated precision production process:

1. Uncoiling → Leveling → Edge Trimming

2. Forming Process: Equipped with 7–9 sets of gradient rollers, gradually rolling and forming to avoid stress concentration problems.

3. High-Frequency Welding: Working frequency 100–500 kHz, the tube blank edge is instantly heated to 1300–1500℃ to achieve melting, and then metallurgical bonding is completed by extrusion rollers. Welding requires no filler metal.

4. Weld Bead Removal → Medium-Frequency Annealing for Stress Relief → Sizing and Straightening

5. Cutting to Length → Performance Testing → Anti-corrosion Treatment → Finished Product Packaging

- Welding Speed: 20–30 m/min, up to 60 m/min

- Weld Strength: Not less than 90% of the base material strength

- Dimensional Tolerances: Outer diameter error ±0.5 mm, wall thickness uniformity ≥98%

Core Advantages

1. Lightweight and Economical: 20%–30% lighter than seamless steel pipes of the same specifications, reducing overall costs by 15%–25%.

2. Precise Dimensions: Smooth pipe surface, strict tolerance control, excellent cold bending and welding performance, and convenient installation.

3. High Production Capacity: Fast welding speed, relying on the factory's large-scale production capacity, enabling rapid and large-volume supply.

4. Stable Welds: Simple stress distribution in a single straight seam, less prone to stress superposition, resulting in better fatigue resistance.

Quality Control System

Strict testing throughout the entire process to ensure product safety:

- Full hydrostatic test: Test pressure 2.5 MPa, pressure holding for 1 minute with no leakage

- Non-destructive testing: Eddy current testing and ultrasonic testing coverage

- Mechanical testing: Conducting multiple tests including flattening, flaring, and tensile testing

- Full traceability: Retaining material reports, furnace batch numbers, and batch production records.

Main Application Areas

Thin Wall Longitudinal Welded steel pipes are suitable for various low-pressure fluid transportation and lightweight structural applications:

1. Building Construction: Steel structure beams and columns, scaffolding, curtain wall supports, handrails

2. Municipal Engineering: Water supply and drainage pipelines, low-pressure gas transmission, fire sprinkler pipes

3. Agriculture and Water Conservancy: Irrigation pipelines, deep well pump pipes, water treatment pipelines

4. Machinery and Light Industry: Conveyor rollers, motor housings, furniture tubing, fitness equipment

5. Power and Communication: Cable protection pipes, conduit pipes, cable tray supports

Real-world Application Case

A large commercial complex project in Shanghai (2024)

Project Requirements: Purchase 12,000 meters of Φ48×3.0 mm Q235B pipe for use as scaffolding and curtain wall support pipes, conforming to GB/T 3091 standard. The pipes must be lightweight, dimensionally accurate, and hot-dip galvanized for corrosion protection.

Zhongtian Solution: Utilizing high-frequency resistance welding technology to produce Thin Wall Longitudinal Welded Steel Pipes with a zinc coating thickness of no less than 30 micrometers.

Application Effects

1. Compared to seamless steel pipes, overall procurement costs are reduced by 22%;

2. Outer diameter tolerance is controlled within ±0.3 mm, resulting in zero non-conforming products during on-site acceptance;

3. Standardized pipe ends improve installation efficiency by 30%;

4. In the five years since its commissioning, the pipes have shown no signs of rust, deformation, or weld damage.

FAQ

Q1: What pressure can Zhongtian thin-walled straight seam welded steel pipes withstand?

A: This product is designed for pressures ≤2.5 MPa, meeting the needs of water supply, gas supply, compressed air supply, and conventional structural applications. It is not recommended for high-pressure applications or temperatures exceeding 450℃.

Q2: How does Zhongtian ensure weld quality and reliability?

A: We use high-frequency resistance welding and strictly control all process parameters, achieving a weld strength of over 90% of the base material. All finished products undergo 100% hydrostatic testing, as well as eddy current and ultrasonic non-destructive testing, and only those that pass are shipped.

Q3: What are the standard delivery times and customization services for our products?

A: For standard specifications of 6 meters and 12 meters, the delivery time is 7 to 10 days. Custom lengths from 1 to 18 meters are available upon request. We also provide hot-dip galvanizing, epoxy coating for corrosion protection, and pipe end processing services such as beveling, threading, and flange making. We accept small trial orders and large bulk orders.