Manufacturing process of butt welding seamless elbow
The manufacturing process of butt-welded seamless elbows is divided into two types: hot-rolled (extruded) seamless elbows and cold-drawn (rolled) seamless elbows due to their different manufacturing processes. Rolled pipes are divided into two types: round pipes and special-shaped pipes.
The process flow of butt welding seamless elbow is briefly introduced as follows:
Cold drawn (rolled) seamless elbow: round pipe blank → heating → piercing → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank pipe → heat treatment → straightening → Hydraulic test (flaw detection) → mark → warehousing.
Hot rolling (extrusion seamless elbow): round pipe blank → heating → piercing → three-roll cross rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing) → cooling → straightening → hydraulic test ( (Or flaw detection) → mark → warehousing.
The raw material for rolling seamless elbows is a round pipe blank. The round pipe blank is cut by a cutting machine into a billet with a length of about one meter, and is sent to the furnace for heating through a conveyor belt. The billet is sent into the furnace for heating, and the temperature The temperature is about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key issue. After the round pipe is out of the furnace, it must be pierced by a pressure punching machine. Generally, the more common punching machine is a tapered roller punching machine. The piercing machine has high production efficiency, good product quality, large perforation diameter expansion, and can wear a variety of round steel.
After piercing, the round pipe blank is successively cross-rolled, continuous rolled or extruded by three rolls. After extrusion, the pipe must be stripped and sizing. The sizing machine rotates a cone drill bit at a high speed into the steel blank to punch holes to form a pipe. The inner diameter of the pipe is determined by The length of the outer diameter of the drill bit of the sizing machine is determined. After the pipe is sized, it enters the cooling tower and is cooled by spraying water. After the pipe is cooled, it will be straightened. After straightening, the pipe is sent to the metal flaw detector by a conveyor belt (Or water pressure test) internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. After the quality inspection of the seamless elbow, it must pass strict manual selection. After the quality inspection of the seamless elbow, use paint Spray the number, specification, production batch number, etc. The seamless elbow is hoisted into the warehouse by a crane.
The rolling method of cold drawn (rolled) seamless steel pipe is more complicated than that of hot rolled (extruded seamless elbow). The first three steps of their production process are basically the same. The difference starts from the fourth step. After emptying, it should be headed and annealed. After annealing, it should be pickled with a special acid liquid. After pickling, oiling. Then it is followed by multiple passes of cold drawing (cold rolling) and then billeting, and special heat treatment. After heat treatment, it must be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. After the steel pipe quality inspection It also needs to go through strict manual selection. After the quality inspection of the steel pipe, the serial number, specification, production batch number, etc. are sprayed with paint, and it is hoisted into the warehouse by a crane.
Source: China Seamless Elbows Manufacturer – Yaang Pipe Industry (www.epowermetals.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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