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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.
Product Description
ST52 seamless mechanical pipe is a high-quality steel pipe widely used in the industrial field.
1. Material standards and grades
- Standard system: It belongs to the European DIN/EN standards (such as EN 10297, EN 10210), corresponding to the German DIN 17100 standard.
- Grade analysis: ST52 is a Structural Steel grade, where "ST" stands for structural steel and "52" indicates a minimum tensile strength of 520 MPa (the actual strength is usually higher).
2. Chemical Composition (Typical Values)
| Element | C (Carbon) | Si (Silicon) | Mn (Manganese) | P (Phosphorus) | S (Sulfur) |
| Content | ≤0.20% | ≤0.55% | 1.00-1.60% | ≤0.035% | ≤0.035% |
- Features: Medium carbon content balances strength and weldability, high manganese content enhances toughness, and low sulfur and phosphorus improve processing performance.
3. Mechanical properties
- Tensile strength (Rm) : 510-650 MPa
- Yield strength (Re) : ≥355 MPa
- Elongation (A5) : ≥21% (gauge length 5 times diameter)
- Impact toughness: ≥27J at room temperature (low-temperature impact may be required depending on specific standards)
4. Manufacturing process
- Hot-rolled seamless tubes: Through hot piercing and rolling, they are suitable for large diameters (such as φ219mm and above) and have a relatively low cost.
- Cold-drawn seamless tubes: Precision cold processing, high dimensional accuracy (tolerance ±0.1mm), smooth surface (Ra≤0.8μm), suitable for precision components such as hydraulic cylinders.
5. Core advantages
- Welded-free structure: Eliminates weld weaknesses and leakage risks, and its pressure resistance is increased by more than 30% compared to welded pipes.
- High strength and lightweight: The yield strength is approximately 40% higher than that of ordinary carbon steel (such as ST37), making it suitable for weight reduction design.
- Processing adaptability: It can be turned, welded (low-hydrogen electrodes are recommended), and cold-bent (bending radius ≥3 times the pipe diameter).
6. Typical application scenarios
- Construction machinery: Excavator hydraulic cylinders, crane booms (need to withstand dynamic loads)
- Automobile manufacturing: Drive shafts, steering system components (requiring high fatigue strength)
- Energy equipment: high-pressure boiler tubes (working pressure ≥20MPa), geothermal well casing
- Special equipment: Gas cylinders, high-pressure reactors (required to pass ISO 9809 certification)
7. Surface treatment and anti-corrosion
- Galvanizing: The thickness of the hot-dip galvanized coating is ≥85μm (EN ISO 1461), and the salt spray resistance test is > 1000 hours.
- Coating: Epoxy resin coating (200-400μm in thickness) is suitable for chemical corrosive environments.
- Phosphating: Improves surface lubricity and is often used in the subsequent deep processing of cold-drawn tubes.
8. Precautions for selection
- Standard differences: EN 10297-1 (General Mechanical tubes) and EN 10216-2 (pressure tubes) have different requirements for impact tests.
- Dimensional accuracy: Cold-drawn tubes can be selected as H9 (precision grade) or H11 (standard grade), while hot-rolled tubes are mostly H12-H13 grades.
- Heat treatment state: Normalizing (+N) state can enhance low-temperature toughness and is suitable for environments below -20℃.
9. Market benchmarking products
- International benchmarking: ASTM A519 of the United States (corresponding grade 4140), STKM13C of Japan (JIS G3441)
- Cost comparison: 40-60% lower than that of stainless steel pipes, but the full life cycle cost needs to be evaluated in a corrosive environment.
ST52 seamless mechanical tubes, with their balanced performance combination, occupy an important position in industrial scenarios that require high strength, reliability and economy. When actually selecting the model, it is recommended to conduct material certification (such as CE/PED certification) in combination with specific working condition parameters (such as pressure cycle times, medium corrosiveness).
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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