Welcome to ALLLAND Steel Pipe Co., Ltd.
Welcome to ALLLAND Steel Pipe Co., Ltd.
ALLLAND Steel Pipe Supply
Alllandsteel is a steel pipe manufacturer based in China with 25 years of experience.
The facility spans 22,000 square meters, represents a RMB 700 million investment, and operates four production lines (JCOE, ERW, SMLS, SSAW) alongside five coating lines.
With an annual production capacity of 250,000 tons, the factory covers specifications ranging from Ø406 to Ø1524 and holds multiple international certifications (API/ASTM/EN/ISO/JIS). Focused on steel pipes, creating value for you!
HOT PRODUCTS
POPULAR ARTICLES
O.D.:
21.3 mm-2540 mm
W.T.:
2.5 mm – 40 mm+
The DIN 30671 standard classifies coating thicknesses based on the operating environment. By selecting the appropriate coating thickness grade for specific operating conditions, it provides the necessary mechanical protection and a waterproof barrier to prevent corrosion.
| Coating Classes | Operating Environment |
| Normal (N) | General soil |
| Medium (M) | Moderately corrosive environments |
| Heavy (H) | Highly corrosive/mechanically stressful environments |
Coating thickness varies depending on the pipe diameter and environmental factors.
| Pipe Diameter Range | PE Thickness (for reference) |
| DN ≤ 100 | 1.8 – 2.2 mm |
| DN 100–500 | 2.2 – 2.8 mm |
| DN ≥ 500 | 2.5 – 3.5 mm |
DIN 30671 sets forth specific requirements for coating performance, specifying the mechanical, durability, and protective properties that must be met.
Tensile Strength: Ensures the coating does not tear under tension.
Elongation at Break: Ensures the coating’s flexibility, preventing cracks caused by pipe bending or foundation settlement.
| Tensile strength | MPa | ≥ 18 – 25 |
| Elongation at break | % | ≥ 350 – 600 |
| Impact resistance | J | No cracking |
Durability primarily encompasses two aspects: resistance to environmental stress cracking (ESCR) and resistance to aging. ESCR ensures that the coating will not crack under long-term stress, which is a key factor in determining its suitability for long-term underground use.
Aging resistance requires that the coating maintain its performance under high-temperature or oxidizing conditions.
Although DIN 30671 is not a construction standard, it establishes clear guidelines for ensuring that the PE layer meets the specified performance requirements.
Surface preparation of steel pipes typically requires blast cleaning, and the cleanliness must meet the Sa 2.5 rust removal standard. The surface roughness should be 40–100 μm to provide an adequate adhesion base for subsequent coatings, particularly 2LPE/3LPE.
Preheating
The most common method for preheating steel pipes is induction heating, with temperatures generally controlled between 180–230°C (adjusted according to the material) to ensure uniform coating formation.
This is a key step in the DIN 30671 installation process, which involves uniformly coating the steel pipe with PE using a die.
| Extrusion temperature | 200–250°C (depending on the type of PE) |
| Extrusion pressure | Ensure a dense coating |
| Coating uniformity | Avoid:Uneven thickness/Bubbles (voids) |
DIN 30671 specifies a comprehensive quality control system that uses testing to verify whether the coating meets performance requirements, ensuring reliable performance in the project.
1. Visual Inspection: Inspect the coating for bubbles, cracks, damage, etc.
2. Coating Thickness Measurement: Use a magnetic gauge to ensure the coating meets the design thickness specifications.
3. Holiday Test: This is a critical test that uses high-voltage electricity to verify that the PE coating is completely sealed.
Common voltage range：
| Coating Thickness | Test Voltage |
| 1.8 mm | 6 – 9 kV |
| 2.5 mm | 8 – 12 kV |
| 3.0 mm | 10 – 15 kV |
DIN 30671 requires that there be no electrical sparks; only products with zero defects are considered acceptable.
4. Mechanical Property Test: tensile test, impact test.
5. Material Property Verification: ESCR test, density/MFR test
DIN 30671 is primarily used for external corrosion protection in water supply, municipal, and general industrial piping systems.
It is particularly suitable for environments where waterproofing and physical barriers are the primary concerns, and can also be used as the outer PE layer in 3LPE systems.
We are located in Hebei, China, and operate a modern production facility equipped with advanced production lines.
Our products are certified to API, ISO, CE, and CNAS standards, ensuring full compliance with international standards.
Our product range includes ERW, HFW, LSAW, and SSAW steel pipes, seamless steel pipes (SMLS), and coated steel pipes: FBE, 3LPE, and DIN 30671 PE coatings.
We conduct multi-stage quality inspections, including non-destructive testing, ultrasonic testing, and coating integrity testing (DIN 30671).
We maintain stable production capacity and strict quality control. With professional packaging and logistics, we guarantee on-time delivery.
Fill in the form below and our team will be happy to assist you
