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About us
Tianjin lefin Industrial
TIANJIN LEFIN STEEL GROUP containing Tianjin lefin Industrial Co.,Ltd. 、Tianjin lefin steel import & export Co.,Ltd and Tianjin Shengqifeng International Trading Co., Ltd. -
Products
Steel Pipe Processing
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard -
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Service Capability
Guarantee Quality
Our steel pipes are suitable for oil, natural gas, shipbuilding, chemical industry, water conservancy, electrical, steel structure, construction and other related fields.
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Has rich experience in steel pipe processing, can be customized according to customer requirements according to the drawing and sample processing, assist in the development of new products.
swaziland BLACK VARNISH COATING ERW PIPE
Product Description
Basic definition and structure
• Base material:
Electric Resistance Welded Pipe (ERW), a steel pipe that is welded by rolling steel strips through the high-frequency resistance welding process. The material is usually carbon steel (such as Q235, ASTM A53) or low alloy steel.
• Coating:
The surface is coated with black Varnish or anti-rust paint to form a uniform and dense protective layer to prevent corrosion and enhance aesthetics.
• Typical use:
Suitable for scenes requiring rust prevention, mild corrosion prevention and appearance, such as building structure, interior decoration, low pressure fluid transportation, etc.
Production process flow
1. ERW steel pipe manufacturing:
• Strip pretreatment → coil forming → high frequency resistance welding → weld grinding → sizing and straightening → Cutting → non-destructive testing (such as ultrasonic or eddy current testing).
2. Coating process:
• Surface treatment: sandblasting or pickling to remove oxide and impurities on the surface of the steel pipe and enhance the adhesion of the coating.
• Primer coating: Spray epoxy primer or zinc-rich primer (optional) to provide basic rust protection.
• Top coat: Spray black varnish or polyester/polyurethane top coat to create an even black coat.
• Curing: Hardening of the coating by baking or natural drying.
Our products
Standard: (Europe) BS EN 10210, BS EN 10219
(American) ASTM A500, ASTM A501
(China) GB/T 3094, GB/T 6728, GB/T 3091
(Japan) JIS G3466
(Australia) AS 1163
Outside diameter: (CHS)20-660mm Wall Thickness: 1.3mm-16mm
Outside diameter: (SHS)20*20-1200*1200mm Wall Thickness: 1.3mm-50mm
Outside diameter: (RHS)20*30-1200*1500mm Wall Thickness:1.2-50mm
Length:4m, 6m, 12m or as your required
Coating characteristics and advantages
Rust and corrosion prevention:
isolated from water, oxygen and corrosive media, suitable for ordinary atmospheric environment or mild humid conditions.
Decorative:
Black matte or glossy surfaces to meet the aesthetic needs of architecture, furniture and other scenes.
Environmentally friendly:
Water-based varnishes or low VOC paints comply with environmental standards (e.g. RoHS).
Economy:
The cost is lower than hot dip galvanizing, spraying and other processes, suitable for projects with limited budgets.
Technical parameters and standards
Steel pipe specifications:
• Outer diameter: 1/2 inch to 24 inches (DN15 to DN600)
• Wall thickness: 1.0mm~20mm (SCH40, SCH80, etc.)
• Length: Usually 6 meters or 12 meters, can be customized.
Coating properties:
• Coating thickness: 20~50 microns (single layer), double layer coating up to 80 microns.
• Adhesion: Grade 1 (no shedding) in the grid test (ISO 2409).
• Salt spray resistance: 500~1000 hours (ASTM B117).
Implementation standards:
• Steel pipe: ASTM A53/A135 (structural), API 5L (pipeline).
• Coating: ISO 12944 (Corrosion resistant coatings), ASTM D7091 (coating thickness test).
Typical application field
1. Architecture and Decoration:
• Indoor and outdoor railings, stair railings, curtain wall supports (black matte finish to enhance the modern feel).
• Furniture frame, display rack, etc. (both rust-proof and beautiful).
2. Low pressure fluid transport:
• Domestic water and air conditioning refrigerant pipes (ensure that the coating is non-toxic and meets hygiene standards).
• Ventilation pipes and cable bushings (black coating conceals well).
3. Mechanical equipment:
• Conveyor frame, agricultural machinery parts (rust resistant and easy to clean).
Comparison with other coatings
Coating Type & Advantages & Limitations
Black Paint Coating：
Advantages in low cost, color control.But its corrosion resistance is weaker than galvanized/spray.
Hot Dip Galvanizing :
It has strong corrosion resistance (more than 50 years of life). But normally high cost, silver gray surface and need two times painting.
Spray (epoxy):
It has high wear resistance, chemical corrosion resistance.But its equipment investment is suitable for mass production.
Selection suggestions
• Normal environment (e.g. indoor drying) :
single layer black varnish coating (economical and practical).
• Humid environments (such as basements) :
double coat primer + top coat (enhanced protection).
• Outdoor long-term use:
It is recommended to choose hot dip galvanizing + black spray (double protection).
Address: Hengtai Road,Daqiuzhuang Town,Jinghai County,Tianjin,China
Mob: +8615122229899(whatspp)
Phone: +86 22 58171905
Fax: +86 22 58171902
E-mail:info@lefinsteel.com
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