Welded steel pipe weld seam style and characteristics
According to the weld seam form and processing technology, welded steel pipe is mainly divided into straight seam welded pipe, spiral welded pipe and other special weld seam forms (such as girth welding, spot welding). Different weld seam styles have their own processing technology, advantages and application fields.
1. Straight seam welded pipe
(1) Processing technology
Plate preparation: Select steel plate or steel strip and cut it into a specified width.
Welding process: Roll the steel plate into a round tube and perform high-frequency resistance welding (ERW) or submerged arc welding (SAW) along the longitudinal direction.
Post-processing: weld seam grinding, heat treatment to eliminate stress, and size correction.
(2) Advantages
High production efficiency: simple processing flow, suitable for mass production.
Low cost: high material utilization rate, lower production cost than other weld seam forms.
Short weld seam: compared with spiral welded pipe, the weld seam length is shorter, reducing the probability of welding defects.
(3) Application field
Construction field: used for scaffolding, guardrails and pipeline support.
Low-pressure transportation: Suitable for conveying low-pressure media such as water, gas, and oil.
Mechanical processing: Used to manufacture parts such as sleeves and support rods.
2. Spiral welded pipe
(1) Processing technology
Sheet preparation: Use wide steel strips to roll into a spiral shape.
Welding process: Use double-sided submerged arc welding (DSAW) technology, and weld the inner and outer welds simultaneously.
Post-processing: Use non-destructive testing and ultrasonic testing to check the weld quality and correct the pipe shape.
(2) Advantages
Strong bearing capacity: The spiral weld is at a certain angle to the axis of the pipe body, which can disperse the axial stress and improve the bearing capacity.
Suitable for large diameters: Suitable for manufacturing steel pipes with larger diameters (up to several meters).
High material utilization rate: Use wide steel strips to reduce waste.
(3) Application areas
Long-distance transportation: Oil and natural gas pipelines, especially large-diameter pipelines.
Infrastructure: Bridges, dock pile foundations, and large-diameter pipes in structural engineering.
Water supply projects: Backbone pipelines of urban water supply networks.
3. Circumferentially welded steel pipe
(1) Processing technology
Sheet forming: bend the steel plate into a ring shape.
Welding technology: use the circular welding process to connect the two ends of the round pipe. Usually, consumable electrode welding or argon arc welding is used.
Post-processing: heat treatment and grinding are performed to improve the performance of the weld.
(2) Advantages
Good pressure resistance: the circular welded structure is suitable for high pressure bearing.
Applicable to thick-walled steel pipes: suitable for processing steel pipes that require a larger wall thickness.
Strong stability: the circular welded structure is uniform and suitable for special mechanical applications.
(3) Application areas
High-pressure vessels: such as boiler pipes and high-pressure gas cylinders.
Special machinery manufacturing: equipment used to withstand high pressure and high temperature.
4. Spot-welded steel pipe
(1) Processing technology
Spot welding positioning: after the steel strip or steel plate is rolled into a round tube, the weld is positioned and fixed by spot welding technology.
Subsequent welding: continuous welding or circular welding is performed to enhance the overall strength.
(2) Advantages
Precise positioning: spot welding can first fix and then strengthen to ensure the accuracy of the weld.
Flexible manufacturing: suitable for small batches and special specifications of pipe manufacturing.
(3) Application areas
Decorative pipes: such as furniture, decorative thin-walled steel pipes.
Special equipment: machinery or parts that require customized production.
5. Special welded steel pipes
(1) Screw welds
Multi-layer spiral welding is used for the manufacture of extremely thick wall steel pipes.
Advantages: Enhanced crack resistance and high pressure resistance.
Applications: deep-sea pipelines, transmission pipelines under extreme conditions.
(2) Internal and external reinforcement welds
Internal and external welding of welds to improve load-bearing capacity and weld strength.
Advantages: Adapt to ultra-high pressure scenarios.
Applications: nuclear power plant pipelines and aviation equipment.
The style selection of welds for welded steel pipes needs to be decided based on specific application scenarios, strength requirements and cost considerations. Through reasonable weld design and process optimization, a variety of industrial needs can be met.
