Detailed explanation of different pipe end treatment technologies for steel pipes

1. Overview of steel pipe end treatment
Pipe end treatment refers to a series of mechanical processing or special treatments performed on the ends of steel pipes to meet specific requirements in terms of connection, corrosion protection, strength, etc. According to international standards such as API 5L and ASTM A53, steel pipe end treatment must follow strict specifications to ensure the safe and reliable operation of the pipeline system.

Core role:

Ensure the sealing performance of pipeline connections

Improve the strength and durability of threaded connections

Easy to install and dock on site

Enhance the corrosion resistance of pipe ends

Adapt to special needs under different working conditions

2. Common steel pipe end treatment types and technical features
1. Plain End (PE)
Basic features:

Maintain the original cut section of the steel pipe

No additional processing

The end may have slight burrs

Processing technology:
After sawing or flame cutting, only simple deburring is performed to keep the cut perpendicular to the pipe axis, and the tolerance is usually controlled within ±1.6mm.

Advantages analysis:

Lowest processing cost

Short production cycle

Suitable for subsequent on-site processing

Application limitations:

Cannot be used directly for socket welding

Need to be used with flanges or special connectors

Relatively poor sealing performance

Typical applications:

Non-pressure conveying system

Structural support pipe

Occasions where on-site secondary processing is required

2. Beveled End, BE)
Technical parameters:

Standard groove angle 30°±5°

Blunt edge height 1.6±0.8mm

Groove surface smoothness requirement Ra≤12.5μm

Processing method:

Mechanical milling: high precision, good surface quality

Flame cutting: economical and efficient, requires subsequent grinding

Plasma cutting: suitable for high alloy materials

Welding advantages:

Increase the penetration area and improve the weld strength

Easy to fill solder and reduce welding defects

Improve stress distribution and reduce the risk of cracking

Quality control points:

Groove angle consistency

Blunt edge dimensional accuracy

Surface oxide layer removal

Groove edge crack-free

Application scenarios:

High-pressure pipeline system (oil, natural gas)

Chemical equipment connection

High-temperature steam pipeline

3. Threaded End (TE)

3.1 Processing standard

API 5B standard thread specification

Taper 1:16 (pipe thread standard)

Thread length varies according to pipe diameter

3.2 Thread type comparison
Type Features Applicable pressure Sealing method
Round thread Simple processing, low cost ≤3000psi thread sealant
Trapezoidal thread High tensile strength ≤10000psi Metal to metal seal
Special buckle Good airtightness Ultra-high pressure Multiple sealing structure
Processing technology control:

Use CNC lathe to ensure accuracy

Thread grease is applied evenly

100% inspection of go and no-go gauges

Magnetic particle detection of cracks

Protective measures:

Installation of thread protection ring

Rust-proof oil application

Special packaging protection

Application precautions:

Avoid repeated disassembly and assembly to damage the thread

Regularly check the sealing condition

Torque control is the key

4. Socket Weld End, SW)
Structural features:

Inner diameter socket structure

Standard insertion depth (1.25 times the pipe diameter)

External fillet weld design

Processing requirements:

Inner surface roughness Ra≤6.3μm

Socket gap 0.8-1.5mm

End face verticality ≤0.5°

Welding process:

Root gap control

Multiple passes welding

Post-weld heat treatment

Advantage areas:

Small diameter high-pressure pipelines

Vibration environment

Space-restricted locations

5. Special pipe end treatment

5.1 Composite treatment

Groove + thread combination

Socket + groove combination

Meet multiple needs

5.2 High-performance treatment
Hardening treatment (induction hardening)

Overlay corrosion-resistant alloy

Shot peening

5.3 Sealing groove design

O-ring groove

Metal sealing ring

Lens pad structure

III. Considerations for pipe end treatment selection

1. Connection method decision
Welding connection → groove end

Threaded connection → threaded end

Flange connection → flat end or small groove

2. Influence of medium characteristics
Corrosive medium → special coating treatment

High-pressure gas → high-precision thread

High-temperature steam → pre-set stress relief groove

3. Pressure level matching
Low-pressure system (≤150psi) → flat end

Medium-pressure system (150-1000psi) → standard thread

High-pressure system (≥1000psi) → special buckle or welding groove

4. Construction condition restrictions
Field operation → consider protection

Limited space → socket type is preferred

Automated installation → high-precision requirements

5. Economic evaluation
Large batch → cost priority

Special working conditions → performance priority

Long-term operation → LCC analysis