Full analysis of ERW welded pipe manufacturing technology
In the field of steel pipe manufacturing, Hebei Huayang Steel Pipe Company has set an industry benchmark in the production of ERW(Electric Resistance Welding) welded pipes by virtue of advanced technology and excellent technology. We are always committed to providing customers with high-quality and high-performance welded pipe products, which can not be separated from a set of rigorous and exquisite production technology.
Raw material control
Quality products begin with quality raw materials. Hebei Huayang Steel Pipe Company carefully selects each batch of steel strip for ERW welded pipe production. We have established long-term and stable cooperative relations with well-known steel production enterprises at home and abroad to ensure that the purchased steel strips meet strict standards in chemical composition and mechanical properties. For each coil of steel strip, we will carry out strict factory inspection, including chemical composition analysis, tensile test, bending test, etc., to ensure product quality from the source. For example, for the commonly used carbon steel strip, we strictly control the contents of carbon, manganese, silicon and other elements, so that it not only has good welding performance, but also can meet the requirements of steel pipe strength and toughness in different application scenarios.
Forming process
Unwinding:
Put the coiled steel strip on the uncoiler, and unfold the steel strip smoothly through precise mechanical control. In the uncoiling process, we use the advanced tension adjustment system to ensure that the steel strip maintains a constant tension during unwinding, avoiding wrinkles or uneven stretching, and laying a good foundation for the subsequent forming process.
Leveling:
The unfolded steel strip often has a certain degree of bending and unevenness, so it needs to be leveled by leveler. Our leveling equipment adopts multi-roller leveling technology, which can accurately adjust the pressure and spacing of leveling rollers according to the thickness and material of steel strip, so that the steel strip can achieve ideal flatness, and the error is controlled within a very small range to ensure the roundness and straightness of the formed steel tube.
Forming:
The leveled steel strip enters the forming machine and is gradually bent into a circle through a series of specially designed forming dies. The forming process is one of the key links in the production of ERW welded pipe. Our technical team carefully designed and debugged the forming die according to the requirements of different specifications of steel pipes to ensure the uniform stress and natural transition of steel strip during the forming process. For example, in the production of small-diameter steel pipes, multi-pass progressive forming process can effectively control the roundness and weld quality of steel pipes; For large diameter steel pipes, advanced roll forming technology is adopted to improve production efficiency and ensure product quality. During the whole molding process, we use high-precision on-line inspection equipment to monitor the size and shape of steel pipes in real time, and adjust them immediately once deviations are found to ensure that each steel pipe meets strict dimensional accuracy requirements.
welding technology
Resistance welding:
the formed steel pipe enters the welding area and is welded by resistance welding process. The advanced ERW welding equipment we introduced can accurately control the welding current, voltage and welding speed. In the welding process, high-frequency current is applied to both sides of the steel pipe weld through the electrode, so that the metal at the weld is quickly heated to a molten state, and then the molten metal is extruded and fused under the action of the extrusion roller to form a firm weld. This welding method has the advantages of fast welding speed, small heat affected zone and high weld quality, which can effectively ensure the welding strength and sealing of steel pipes. For example, when welding high-strength steel grade ERW welded pipe, we optimize the welding parameters to make the strength of the weld reach or even exceed the strength of the base metal, which meets the strict engineering application requirements.
Weld treatment:
after welding, there will be some bumps and unevenness at the weld of the steel pipe, which needs weld treatment. We use advanced weld grinding equipment to polish and trim the weld accurately, so that its surface is smooth and level with the base material of steel pipe. At the same time, through on-line nondestructive testing equipment, such as ultrasonic flaw detector and eddy current flaw detector, the weld is comprehensively tested to ensure that there are no defects such as porosity, cracks and inclusions in the weld, and that each ERW welded pipe leaving the factory has excellent quality.
Sizing and finishing
Sizing:
After welding and weld treatment, steel pipes need to be sized to ensure the accuracy of their outer diameter. Our sizing equipment adopts advanced three-roller or four-roller sizing technology, which can accurately adjust the position and pressure of the sizing roller according to different pipe diameter requirements, so that the outer diameter of the steel pipe is accurately controlled within the standard tolerance range when passing through the sizing machine. In the process of sizing, the roundness of the steel pipe is further optimized to ensure the geometric dimension accuracy of the steel pipe.
Cutting:
cut the steel pipe after sizing according to the length required by customers. We use high-precision flying saw cutting equipment, which can cut the steel pipe accurately and quickly under the condition of high-speed operation, and the incision is smooth and smooth, without burr and deformation. The length error of the cut steel pipe is controlled within a very small range, which meets the strict requirements of customers for product length accuracy.
Hydrostatic test:
In order to test the pressure-bearing capacity and tightness of steel pipes, every ERW welded pipe should be subjected to strict hydrostatic test. Our hydraulic test equipment can simulate different working pressure environments and conduct comprehensive pressure tests on steel pipes. During the test, both ends of the steel pipe are sealed, high-pressure water is injected into the pipe, and it is kept under the specified pressure for a certain time to observe whether there is leakage in the steel pipe. Only the steel pipes that pass the water pressure test can enter the next process, ensuring that every steel pipe that leaves the factory has reliable quality and safety performance.
Surface treatment:
Finally, in order to improve the corrosion resistance and appearance quality of the steel pipe, we carry out surface treatment on the steel pipe. According to customers' needs, we can choose different surface treatment methods such as zinc plating, painting and plastic spraying. For example, hot dip galvanizing can form a dense zinc layer on the surface of steel pipe, which can effectively prevent steel pipe from rusting and prolong its service life; Painting and plastic spraying can make the steel pipe surface more beautiful and provide some protection.
Through strict control and careful optimization of every link of ERW welded pipe manufacturing process, Hebei Huayang Steel Pipe Company embodies our professionalism and dedication in every process from raw materials to finished products. We will continue to uphold the spirit of innovation, constantly improve the technological level, provide customers with more high-quality and reliable ERW welded pipe products, and contribute our strength to the development of various industries.
