Straight Seam Welded ERW Steel Pipe
Tianjin shenzhoutong steel pipe co.,ltd is one of the leading Straight Seam Welded ERW Steel Pipe manufacturers in China.
Straight Seam Welded ERW Steel Pipe is a high-performance industrial piping solution manufactured by rolling steel coils into a cylindrical shape and welding the seam using high-frequency electrical resistance. This manufacturing process ensures a consistent, strong, and cost-effective pipe suitable for a wide range of structural and fluid transport applications.
Products Description
Product | Straight Seam Welded ERW Steel Pipe | |
Process | Electrical Resistance Weld | |
Production Stardard | API 5L , API 5CT, ASTM A53 , ASTM A36, ASTM A500, EN10219 | |
Grade | A, B, X42, X46, X52, X56, X60, X65, X70, Q235, Q355, S235, S355, SS400... | |
Size Range | OD 1/2"-26"(21.3-660mm), Thickness 0.055"-1.602"(1.65-26.97mm) | |
Pipe Length | 5.8m, 6m,12m,as requirement | |
Pipe Ends | Plain, Bevel, Threading and coupling, Grooved | |
Surface Treatment | bare, black paint, anti-rust oil,galvanized , FBE, epoxy,3LPE, 3LPP | |
Application | oil , gas, water transportations, industires, Structure. Piling | |
manufacturing
The production of ERW steel pipes involves several critical stages:
Raw Material Preparation: Hot-rolled or cold-rolled steel coils are uncoiled, leveled, and trimmed to the required width.
Forming: The steel strip passes through a series of forming rolls that gradually bend it into a circular tube shape.
High-Frequency Welding:
Utilizing the skin effect and proximity effect of high-frequency current (typically 350-450 kHz), the edges of the tube billet are heated to a molten state without adding filler metal.
Squeeze rollers apply pressure to forge the edges together, creating a solid-state bond.
Flash Removal: Internal and external weld flashes (excess metal) are trimmed off using scarfing blades to ensure a smooth surface.
Post-Weld Heat Treatment (PWHT): To restore the microstructure and eliminate residual stresses caused by welding, the weld zone undergoes online heat treatment (such as normalizing, annealing, or quenching and tempering). This step is crucial for ensuring uniform mechanical properties across the pipe.
Sizing and Straightening: The pipe is passed through sizing mills to achieve precise outer diameter tolerances and straightened to ensure geometric accuracy.
Non-Destructive Testing (NDT): Comprehensive inspection including ultrasonic testing (UT) for weld defects, eddy current testing, and hydrostatic pressure testing to guarantee quality.
Surface Treatments & Coatings
To enhance corrosion resistance and extend service life, especially in harsh industrial or underground environments, Straight Seam Welded ERW Steel Pipes undergo various surface treatments:
Black Painted/Varnish: Basic protection against atmospheric rust during storage and transit.
Galvanized: Hot-dip or electro-galvanized coatings provide superior corrosion resistance, suitable for outdoor structures and water systems.
Anti-Corrosion Coatings: Advanced options include FBE (Fusion Bonded Epoxy), 3LPE/3LPP (Three-Layer Polyethylene/Polypropylene), Epoxy, and PE coatings for aggressive chemical or soil conditions.
Oiled/Bare: Light oiling for temporary protection; bare finish for immediate processing or painting by the end-user
Product Advantages
Preciser Tolerance: Unlike seamless pipes, ERW pipes are produced from hot-rolled or cold-rolled steel strips, allowing for precise control over wall thickness and diameter tolerances.
Cost-Effectiveness: Provides an optimal balance of performance and affordability compared to seamless or specialty alloy pipes.
Durability and Strength: The ERW manufacturing process and carbon steel material yield a pipe with high tensile strength and good load-bearing capacity, ensuring long service life.
Ease of Installation and Fabrication: Lightweight yet robust, it is easy to transport, cut, weld, and install on-site, significantly reducing labor time and project costs.
Versatility: Available in multiple diameters, wall thicknesses, and can be customized in length and surface treatment, catering to specific project requirements.
