Seamless Steel Tube Production Process and the Notices When Buying Pipes

Thick wall seamless steel tube production process
Cutting the circular tube embryo to about 1 meter of billet by cutting machine. The thick wall steel pipe is the pipe that the ratio between outer diameter and thickness is less than 20.
Thick wall steel tube is mainly used for petroleum geological drill pipe, oil chemical industry with the cracking of pipe, boiler tube, bearing and automobile, tractor, aviation with high precision tube structure, etc.
Thick wall steel pipe seamless steel pipe manufacturing process:
Hot rolled (extrusion seamless steel tube) circular tube billet → heating → punch → three-roll skew rolling, rolling or pressing → unlocking → pipe-sizing (or reducing) cooling → straightening →hydrostatic test or inspection marks → warehousing.
The round billet is the raw material to roll seamless pipe. And send round billet to heating furnace by the conveyor belt. Billet are fed into the furnace heating and the temperature should be about 1200 ℃. Fuel should be hydrogen or acetylene. In furnace temperature control is a critical problem. After taking out from the furnace, the circular tube billet should be punched.
Generally, the common punch is tapered roller puncher, this kind of puncher has high production efficiency, good product quality, large amount of perforated hole enlargement, and it can wear a variety of steel grade. After perforation, circular tube billet has been three-roll skew rolling, rolling or extrusion. To take off after extruding tube sizing. Sizing mill goes into embryo punching and forming steel pipe. Steel pipe diameter is determined by the outer diameter of sizing mill bit. Steel pipe after sizing, into the cooling tower, by water spray cooling, steel pipe after cooling will be straightening. Steel pipe by the conveyor belt to the metal detection after straightening machine (or water pressure experiment) for internal inspection. If the steel pipe has internal crack, air bubble, it will be detected. After quality detection, the steel pipe will be rigorously selected. And then painted number, specification, batch number, etc on it. And then put them in the warehouse.
Questions should be noticed when buy pipes
1. The material
Many enterprises to adopt the irregular material, usually refers to the nickel content. Although you can use potions to distinguish, but this is clearly erroneous zone, because small burden nickel only with seven can’t be distinguished. But the raw material price is very different, this is one of the false. Especially 321 high nickel and 316 high nickel do fake is very severe.
2. The size
Many customers has no inspection technical support. For example pipe with 90 degree angle, the regular R=1.5D, but in the market, lots of the production mold R>1.25 D, but the weight is very different. And it is much shorter than the standard.
3. The thickness
The customers now are very smart, of course, and they will use the caliper to measure the thickness, although sometimes the customer think the thickness is barely reached the standard, they ignored the thickness of the back arc. Because in the process of the elbow push system, the wall will be reduced, so the diameter can barely reach the standard, but the back is unqualified.
4. Solid solution treatment and nondestructive testing, rolling sand and sand blasting process
5. Seamlessly welding
Seamlessly welding is to make the surface of the welded elbow has no sign of any welding by polished pickling after sandblasting, even can’t see the welded elbow by using the advanced detection equipment.
6. Spot welding & repair welding

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Post time: May-16-2017
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