How to distinguish ERW steel pipe and UOE steel pipe?

1. Differences in raw materials and production capacity

The erw pipe is made of hot rolled coil, and the UOE steel pipe is made of hot rolled steel. Therefore, ERW steel pipe can realize continuous assembly line operation, high production efficiency and low production cost; while UOE steel pipe is used for processing, it cannot realize continuous assembly line operation, low productivity and high production cost. The maximum thickness of ERW steel pipe coil is limited, the maximum thickness can be 25mm, and the maximum diameter can be 660mm; the maximum thickness of UOE steel pipe can be 40mm, and the maximum diameter is only limited by the width of the plate. Currently, the maximum diameter can be 1422mm.

Second, the difference between welding
ERW pipe welding without additional wire; UOE pipe requires wire.

3. Appearance difference
The internal and external welds of ERW steel need to be removed, so the anti-corrosion effect is good; UOE pipe wall welds not only have the disadvantage of high anti-corrosion.

Fourth, the difference between purchase cost and difficulty
The purchase cost of ERW steel pipe is low, and the cost of UOE steel pipe is very high, and the general price difference is 15%-25%. Domestic UOE steel pipe manufacturers have few procurements and are very difficult. When the diameter is <Φ406mm, the difference in purchasing cost is greater. ERW steel pipe manufacturers are relatively difficult to purchase. When the diameter is less than Φ406mm, the purchase cost will be reduced.

Five, application difference
ERW steel pipes are mainly used for onshore long-distance pipelines such as natural gas, refined oil, crude oil, and pulp. UOE steel pipes are mainly used in high-pressure submarine long-distance pipelines, alpine regions, and land areas of Class II, III, and IV.

HFW And ERW

High-frequency welding(HFW) is a solid resistance heat energy. The use of high-frequency current welding resistance heat generated in the workpiece so that the workpiece is heated to melt the welding area or near the surface of the plastic state, then applied (or not applied) forging force and achieve a combination of metals. Therefore, it is a solid phase resistance welding. High-frequency welding: high-frequency current through the metal conductor, will produce two peculiar effects: skin effect and proximity effect, high frequency welding is performed using these two effects of the seamless pipe, these two effects is to realize a metal at high frequency welding base.

High frequency welding is the use of the skin effect of high-frequency energy is concentrated on the surface of the current workpiece; the use of proximity effects to control the position and extent of the flow path of the high frequency current. Current speed is very fast, it can be in a very short period of time the adjacent plate edge heated, melted, and extruded through docking. Frequency welding method according to a high frequency current to generate heat in the workpiece can be divided into to contact with high-frequency welding and high frequency induction welding. Contact frequency welding, high frequency current through the mechanical contact with the workpiece while the workpiece passed. High frequency induction welding, the high-frequency current through the coupling of the workpiece external induction coil to generate induced currents in the workpiece. High-frequency welding is a highly specialized welding method, according to the product is equipped with special equipment. High productivity welding speeds of up to 30m/min. Mainly used for longitudinal seam or spiral seam welded pipe manufacturing.

Electrical resistance weld(ERW) is the combination of applying pressure to the workpiece through the electrode, a method using welding current through a resistor in thermal contact with the joint surface and the surrounding area generated. Resistance by the current flowing through the thermal effect of resistance welding a workpiece contacting surface of the surrounding area is heated to produce molten or plastic state, so as to form a metal bonding method. There are four main resistance welding method that spot, seam welding, projection welding, butt welding. Resistance welding uses a pressure-free filler metal welding, the weld is not filled with other ingredients, skin effect against high frequency current and proximity effect, the plate is heated to welding temperature side instantly, formed by the squeeze roller extrusion weld forging organization. Require the use of high-quality steel pipe weld heat treatment online or offline, so that the weld zone structure refinement, quality ERW pipe weld and base metal may reach the same level of toughness, which is submerged arc welding process can not be achieved.

Read more ： seamless carbon steel pipe

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