The common production processes and characteristics of LSAW Steel Pipes are as follows:

JCOE molding process

Process steps: First, mill the steel plate to achieve the required width, parallelism, and groove shape of the steel plate edge; Then use a pre bending machine to pre bend the edges of the steel plate; Then, on the JCO forming machine, half of the pre bent steel plate is subjected to multiple step stamping to press it into a "J" shape, and the other half is also bent into a "C" shape, finally forming an open "O" shape; Afterwards, pre welding is carried out to ensure that the formed straight seam welded steel pipes are joined and continuously welded using gas shielded welding; Then perform internal welding and external welding separately, both using longitudinal multi wire submerged arc welding; After welding is completed, ultrasonic inspection, X-ray inspection, diameter expansion, hydrostatic test, chamfering, ultrasonic inspection again, X-ray inspection, pipe end magnetic particle inspection and other testing processes are carried out in sequence. After passing the inspection, anti-corrosion and coating are carried out according to user requirements.

Features: Uniform distribution of forming stress, regular shape of the tube, wide range of product specifications, high flexibility, can achieve any size of product within the production range, and can adapt to the production needs of multiple varieties and small batches; The requirements for raw materials are relatively low, and a wide range of steel plates can be used; The investment in production equipment is relatively small, the operating cost is low, but the production efficiency is slightly lower compared to UOE process.

UOE Forming Process

Process steps: The steel plate is bent into shape using a U-shaped press and an O-shaped press. The steel plate is first processed by a mechanical edge planing machine, and then pre bent using a plate edge pre bending machine. Then, it is pressed into a "U" shape on the U-shaped press, and finally into an "O" shape on the O-shaped press; Subsequently, welding is carried out using internal and external welding equipment with multiple welding wires; After welding, mechanical or hydraulic expansion can be used according to user requirements; Finally, a series of inspection processes are carried out, including ultrasonic inspection, X-ray inspection, hydrostatic testing, etc., to ensure the quality of the steel pipe.

Features: High production efficiency, stable product quality, high dimensional accuracy, excellent performance in roundness, straightness and other indicators of steel pipes; The expansion process can effectively eliminate the internal stress generated during the forming and welding process of steel pipes, and improve the comprehensive performance of steel pipes; However, the equipment investment is large, the operating cost is high, and strict requirements are placed on the width and thickness tolerances of raw materials, making it suitable for large-scale, single specification steel pipe production.

Roll forming submerged arc welding process

Process steps: The steel plate is rolled into a circular billet by a rolling machine, and multiple curls and adjustments may be required during the rolling process to achieve the appropriate diameter and roundness; Then welding is carried out, starting with internal welding and then external welding, usually using submerged arc welding; Perform non-destructive testing on the weld seam after welding, such as ultrasonic testing, X-ray testing, etc., to check the quality of the weld seam; Finally, according to the needs, the overall expansion of the steel pipe, water pressure testing and other processes are carried out to improve the dimensional accuracy and performance of the steel pipe.

Features: The equipment is relatively simple, the investment cost is low, the production flexibility is high, and it can produce steel pipes of different diameters and wall thicknesses; It has certain advantages for the production of small batches and special specifications of steel pipes; However, the dimensional accuracy and weld quality of the produced steel pipes may be slightly lower compared to JCOE and UOE processes, especially for large-diameter steel pipes where roundness and straightness control are more difficult and production efficiency is lower.

Comparison between LSAW steel pipe production processes:

1. In terms of molding quality

JCOE process: The formed steel pipe has a regular shape and a relatively uniform stress distribution. Through multiple stamping processes, the dimensional accuracy of the steel pipe can be effectively controlled, and it performs well in terms of roundness and straightness. However, compared to the UOE process, its accuracy may be slightly inferior. For example, the roundness error of large-diameter steel pipes produced by JCOE process may be controlled within ± 1.0%, while UOE process can achieve within ± 0.5%.

UOE process: Due to the use of specialized U-shaped and O-shaped presses for forming, the dimensional accuracy of steel pipes is very high, with roundness and straightness being its advantages. The steel pipes produced by this process can better meet high-precision requirements, such as deep-sea oil pipelines and other projects that require extremely high installation accuracy.

Roll forming process: It is relatively weak in terms of dimensional accuracy, especially in controlling the roundness and straightness of large-diameter steel pipes. For example, the roundness error of large-diameter steel pipes produced by the rolling forming process may reach about ± 1.5% - ± 2.0%, and the uniformity of pipe wall thickness is also slightly poor. However, for some situations where shape accuracy is not particularly high, such as ordinary onshore oil and gas gathering and transmission branch lines, it can still meet the requirements.

2. In terms of production efficiency

JCOE process: The production efficiency is relatively moderate, and its forming process is relatively complex. Each stamping requires a certain amount of time, and different specifications of products need to adjust mold and other parameters. However, its equipment is relatively flexible and can maintain a certain efficiency in multi variety and small batch production. For example, the JCOE production line may take 15-20 minutes to produce a steel pipe with a diameter of 1000mm and a length of 12m.

UOE process: It is an efficient production process, with specialized forming equipment and automated welding systems that make the production process fast and smooth. Once the equipment is debugged and suitable for production of specific specifications, steel pipes of the same specifications can be produced in large quantities and quickly. For steel pipes with the same diameter of 1000mm and length of 12m, the UOE production line may only take about 10-12 minutes.

Roll forming process: The production efficiency is low, the rolling process is relatively slow, and it takes a lot of time to adjust parameters such as pipe diameter and wall thickness. In addition, the inspection and correction processes after welding may also be more complex, resulting in slower overall production speed. Producing steel pipes of the same specifications may take 20-30 minutes or even longer.

3. Equipment investment and cost aspects

JCOE process: Equipment investment is relatively small, it does not require large U-shaped and O-shaped presses like UOE process, and the requirements for plant and infrastructure are also relatively low. The operating cost mainly lies in the energy consumption of stamping equipment and the maintenance of molds, and the cost is relatively moderate. For some small and medium-sized steel pipe production enterprises, it is a relatively economical choice.

UOE process: The equipment investment is huge, requiring high-precision U-shaped and O-shaped presses, large welding equipment, and advanced diameter expansion devices. And the maintenance and upkeep costs of these devices are also high, requiring a high level of technical proficiency from the operators. However, due to its efficient production capacity, costs can be shared during large-scale production.

Roll forming process: The equipment is simple, and the investment cost is the lowest among the three processes, requiring only basic equipment such as rolling machines and welding equipment. The operating cost is mainly due to the energy consumption of the rolling machine and the consumption of welding materials, and the cost is relatively low. This gives it certain advantages in small-scale, special specification, or cost sensitive production projects.

4. In terms of adaptability of raw materials

JCOE process: The requirements for raw material steel plates are relatively low, and it can adapt to a wide range of steel plate widths and thicknesses, which gives it greater flexibility in raw material procurement. For example, it can be produced using steel plates with a width range of 1500-3000mm and a thickness of 8-40mm.

UOE process: Strict requirements are placed on the width and thickness tolerances of raw materials, as its forming process heavily relies on the dimensional accuracy of steel plates. Usually, it is necessary to use steel plates with high dimensional accuracy, such as steel plates with width tolerances controlled within ± 5mm and thickness tolerances controlled within ± 0.5mm.

Roll forming process: It can also adapt to various specifications of steel plates, but for thicker steel plates, rolling may encounter some difficulties, such as cracks and other defects that are prone to occur during the rolling process. In terms of raw material thickness, it is generally suitable for steel plates with a thickness of 6-30mm.