3PE anti-corrosion large-diameter spiral steel pipe refers to a three-layer polyolefin coating (MAPEC) external anti-corrosion steel pipe, which is a commonly used anti-corrosion pipeline in China. Other anti-corrosion methods include IPN8710, FBE epoxy powder, and epoxy coal tar.

3PE anti-corrosion generally consists of three layers of structure:

First layer epoxy powder (FBE>100um)

Second layer adhesive (AD) 170-250um

Third layer polyethylene (PE) 2.5-3.7mm

In practical operation, the three materials are mixed and integrated into one, and processed to firmly bond with the steel pipe to form an excellent anti-corrosion layer. Its processing methods are generally divided into two types: winding and circular mold wrapping.

3PE anti-corrosion large-diameter spiral steel pipe standard

The SY/T0413-2002 standard is implemented domestically and came into effect on August 1, 2002. The standard mainly specifies polyethylene and high-density polyethylene, with a Vicat softening point set at not less than 110 ℃; The thickness of the external anti-corrosion layer is determined according to the German standard DIN30670-1991, which mainly uses low and medium density polyethylene. Greatly improved the impact resistance of the 3PE anti-corrosion coating. SY/T0413-2002 significantly improves the peel strength and impact resistance indicators of the 3PE anti-corrosion layer, and specifies the mechanical strength and weather resistance of the 3PE anti-corrosion layer based on the carbon black content of some special materials. It also increases the sampling frequency of the joint peeling strength (i.e. the peeling strength of the heat shrink sleeve and heat shrink tape to the primer steel).

Common spiral welding materials for 3PE double-sided submerged arc welded spiral steel pipes:

L360 Specification: 406 * 8.5 Execution Standard: GB/T9711.2-1999 Testing Methods: Ultrasonic, X-ray, Water Pressure Application: Large scale natural gas transportation projects in China.

Characteristics of 3PE double-sided submerged arc welding spiral steel pipe technology: 1. During the steel pipe forming process, the steel plate deforms uniformly, residual stress is small, and the surface does not produce scratches. The processed steel pipes have greater flexibility in the size specifications of diameter and wall thickness, especially in the production of high-grade thick walled steel pipes, especially large-diameter thick walled pipes, which have unparalleled advantages compared to other processes and can meet more requirements of users in terms of steel pipe specifications;

2. Adopting the process of pre welding followed by internal and external welding (precision welding), welding can be achieved at the optimal position, which is less prone to defects such as misalignment, welding deviation, and incomplete penetration, and easy to control the welding quality;

3. Conducting overall mechanical diameter expansion can effectively improve the dimensional accuracy of steel pipes and improve the distribution of internal stress, thereby avoiding damage caused by stress corrosion and facilitating on-site welding construction;

4. Conduct 9 100% quality inspections on steel pipes, ensuring that the entire process of steel pipe production is under effective detection and monitoring, effectively guaranteeing the quality of submerged arc welded steel pipe products;

5. All equipment on the entire production line has the function of networking with the computer data acquisition system to achieve real-time data transmission. The central control room collects technical parameters and quality indicators during the production process.