Elbow type steel-plastic conversion

The elbow welded steel-plastic conversion joint realizes the transition connection between PE pipe and metal pipe through the welding of steel pipe end and metal locking ring, and its core technical characteristics are as follows:
1. Structural design and connection reliability
2. Materials and anti-corrosion systems
3. Adapt the installation specifications to the scene
? Welding process requirements: argon arc welding is required to make the bottom (GB 50236), 100% radiographic inspection of the weld (grade III qualified), and 0.6MPa air tightness test after welding (no bubbles in soapy water detection).
? Buried depth: The buried depth in the gas project is ≥ 1.2m (the roadway ≥ 1.5m), and the backfill needs to be compacted with fine sand to avoid damage to the anti-corrosion layer by stones.
? Core Application Scenarios:
? Gas main pipe and branch pipe connection: DN200 specification is used for urban medium pressure gas network (0.4MPa), with 3PE anti-corrosion, can withstand soil stress and cathodic protection interference.
? Chemical high-pressure pipeline: DN80 specification is used for hydrochloric acid (concentration ≤30%) transportation, FBE anti-corrosion layer (thickness 400μm) temperature resistance 80 °C, in line with GB5044-2008 occupational exposure to poison classification standard.
The elbow external threaded steel-plastic conversion joint is connected with the metal pipe fitting through the external thread of the steel pipe end, and its technical characteristics are as follows:
1. Connection and quick installation
2. Materials and anti-corrosion design
3. Adapt the installation specifications to the scene
? Threaded connection requirements: the thread needs to be screwed into the depth of ≥8 teeth (DN32 specification), the torque is controlled at 30~50N·m, and the pressure test of 0.4MPa (pressure drop ≤ 0.01MPa/10 minutes) is carried out after installation.
? Burial restriction: only shallow burial (burial depth ≤ 0.8m) is allowed, and concrete casing protection is required to avoid loosening of the thread due to soil stress for a long time.
? Core Application Scenarios:
? Gas entrance branch: DN32 specification is used for the back pipe of the gas meter in residential buildings, and the external thread is connected to the metal ball valve, and the exposed part is convenient for daily maintenance after installation.
? Temporary piping system: DN50 specification is used for temporary water supply at the construction site, and the external thread can be quickly connected to the galvanized steel pipe, which can be disassembled and reused after the project is completed.
3. The core differences between the two types and the selection suggestions
Comparison dimension: Elbow welded type Elbow external threaded type
Working pressure: 0.4~1.0MPa (preferred for high-pressure scenarios) ≤0.6MPa (low-pressure/temporary scenarios)
Long installation cycle (welding, flaw detection, anti-corrosion) Short (thread tightening is sufficient)
Anti-corrosion cost: High (3PE/FBE anti-corrosion), Low (hot-dip galvanized, protective cover)
Applicable medium: gas, chemical corrosive fluid, high-pressure water, low-pressure gas, water, non-corrosive liquid
Typical Scenarios Buried Trunk Pipes, Chemical Workshop Pipes, Indoor Branch Pipes, Temporary Works, Narrow Spaces
The core value of elbow welded and externally threaded steel-plastic conversion is to flexibly adapt to different pressures, environments and installation conditions, and to ensure that it meets mandatory standards such as GB/T 26255-2022 when selecting the model.