In many fields of modern industry, high frequency welded pipe, as an important pipe product, plays an indispensable role. From building structures to automobile manufacturing, from mechanical engineering to household items, high-frequency welded pipes are everywhere. So, what is the high frequency welded pipe, and how is it produced and applied? This article will reveal the mystery of high frequency welded pipe for you.
Basic principle of high frequency welded pipe
High frequency resistance welded pipe, short for high frequency welded pipe, its welding principle is based on the skin effect and proximity effect of high frequency current. When the high frequency current passes through the metal strip to be welded, the current will concentrate on the metal surface flow, which is called the skin effect. At the same time, due to the interaction of current, the adjacent metal surface will generate strong resistance heat, so that the metal is quickly heated to the welding temperature. Under a certain pressure, the heated metal quickly fuses to form a strong weld, thus completing the welding process. This welding method has the advantages of fast welding speed, high production efficiency and good weld quality.
Production process of high frequency welded pipe
Raw material preparation
Raw material preparation is the beginning of the production process of high-frequency welded pipe, and also the basis for ensuring the quality of welded pipe, which plays a decisive role in the performance of the final product. Usually, high-quality hot rolled or cold rolled steel strips are used as raw materials, and these two kinds of steel strips have their own characteristics. Hot-rolled steel strip has relatively low cost, high production efficiency, good toughness and ductility, and is suitable for conventional welded pipe production with relatively less stringent strength requirements. Cold rolled steel strip after cold rolling processing, the surface is more smooth, higher dimensional accuracy, mechanical properties are more superior, often used in the manufacturing of high precision, high strength requirements of high frequency welded pipe.
In terms of chemical composition, the content of carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S) and other elements in the steel strip has strict standards. Carbon content directly affects the strength and hardness of the steel strip, too high carbon content will lead to poor welding performance, and too low carbon content will cause insufficient strength; Silicon can enhance the strength and hardness of steel, but excess will reduce the plasticity and toughness; Manganese can improve the strength, hardness and wear resistance of steel, and improve the weldability of steel. Phosphorus and sulfur are harmful elements, phosphorus will make steel with cold brittleness, sulfur will make steel hot brittleness, so their content must be strictly controlled at a very low level.
In terms of mechanical properties, the steel strip must have appropriate yield strength, tensile strength and elongation. The yield strength ensures that the steel strip will not easily undergo plastic deformation during processing and use. The tensile strength ensures that the welded pipe will not be broken when subjected to tension; Elongation reflects the plastic deformation ability of the steel strip, and sufficient elongation can ensure that the steel strip bends smoothly in the forming process without cracks.
Surface quality is also crucial. There should be no obvious scratches, cracks, scars, scales and other defects on the surface of the steel strip. Scratches and cracks will become the stress concentration point of welded pipe during use, reducing the strength and service life of welded pipe; Scarring will affect welding quality and lead to weld defects. The iron scales will hinder the fusion of metals during welding, reducing the strength of the weld seam. Before the raw materials are stored, a variety of detection means will be used, such as naked eye observation, non-destructive testing, metallographic analysis, etc., to strictly control the quality of the steel strip, and only the steel strip that fully meets the standards can enter the subsequent production link.
Molding
Through a series of forming rolls, the steel strip is gradually bent into circle or other specific shapes. The molding process requires precise control of roll spacing and Angle to ensure dimensional accuracy and shape accuracy of the pipe.
Welding
When the pipe enters the high frequency welding area after molding, through the action of high frequency current, the butt edge of the pipe quickly heated and fused. In the welding process, it is necessary to strictly control the welding current, voltage and welding speed to ensure the quality of the weld seam.
Sizing
There may be a certain size deviation of the welded pipe, and the pipe is accurately adjusted by the sizing machine to make it reach the specified outer diameter and wall thickness.
Cutting off
According to the actual use requirements, the pipe after sizing is cut off according to a certain length. In cutting methods, there are usually flying saw cutting and grinding wheel cutting.
Inspection
Carry out a comprehensive quality inspection of the produced high frequency welded pipe, including appearance inspection, size measurement, water pressure test, tensile test, etc., to ensure that the product meets the relevant standards and requirements.
Advantages of high frequency welded pipes
High production efficiency: high frequency welding speed is fast, which can achieve continuous production, greatly improve production efficiency and reduce production costs.
Good weld quality: Due to the skin effect and proximity effect of high-frequency current, the metal at the weld is heated evenly, the welding quality is high, and the weld strength is close to the base metal.
High dimensional accuracy: Through advanced molding and sizing processes, high-frequency welded pipes can achieve high-precision dimensional control to meet the needs of various precision applications.
High material utilization rate: high-frequency welded pipe in the production process results in less waste, high material utilization rate, in line with the development concept of energy saving and environmental protection.
As an important pipe material, high-frequency welded pipe plays an important role in modern industry by virtue of its unique welding principle, efficient production process and wide application fields. With the continuous progress of science and technology and the continuous improvement of the process, the performance and quality of high-frequency welded pipes will continue to improve, providing strong support for the development of more fields.
Application of high frequency welded pipe
Construction industry: high frequency welded pipe is widely used in scaffolding, steel structure frame, door and window frame, etc, in building structure. Its high strength, corrosion resistance and good processing properties make it ideal for the construction industry.
Automobile manufacturing: in this field, high frequency welded pipes are used to manufacture automobile frames, chassis, bumpers and other components. Because of its light weight and high strength, it can effectively reduce the weight of the car and improve fuel economy and driving performance.
Mechanical manufacturing: high-frequency welded pipe can be used to manufacture various structural parts, transmission parts, etc of mechanical equipment. Its high precision and good mechanical properties can meet the strict requirements of mechanical equipment for pipes.
Household goods: In this field, high frequency welded pipes are often used in the manufacture of furniture, drying racks, fitness equipment, etc. Its beautiful appearance and good durability are loved by consumers.
