Straight seam steel pipe continuous rolling process: straight seam steel pipe continuous rolling process, the continuous rolling process is used in the continuous rolling and fixed diameter reduction process of steel pipes. Steel pipe continuous rolling is a process in which the steel pipe and the mandrel move together in multiple stands. The deformation and movement of the steel pipe are affected by the joint action of the rollers and the mandrel. The mandrel can be free-floating, which means it moves forward entirely driven by the metal; it can also be limited, which means the mandrel is given a movement speed to limit its free movement. During the movement, the mandrel, roll, and steel pipe are connected as a whole, and changes in any one of them will cause changes in the state of the entire system. The continuous rolling theory is a theory that studies the interrelationship between them.
Kinematic phenomena of steel pipe continuous rolling
①Kinematic phenomena;
②Slip phenomenon;
③Tension coefficient.
Analysis of the motion state of continuous rolled pipes
①The displacement relationship between the rolled piece and the mandrel;
②Rack and its determination;
③Intermittent rolling analysis;
④ Single machine rolling mandrel movement characteristics.
Deformation and stress during continuous rolling of steel pipes
① Internal stress analysis of continuous rolled pipes;
② Side wall deformation and stress analysis.
Welded pipes are classified by use: According to use, they are divided into generally welded pipes, galvanized welded pipes, oxygen-blown welded pipes, wire casings, metric welded pipes, idler pipes, deep well pump pipes, automotive pipes, transformer pipes, welded thin-walled pipes, and welded special-shaped pipes and spiral welded pipe.
General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steels that are easily weldable. Steel pipes are subject to hydraulic pressure, bending, flattening, and other experiments, and there are requirements for the surface. The delivery length is usually 4-10m and delivery of fixed length (or multiple lengths) is often required. The specifications of welded pipes are expressed in nominal diameter (millimeters or inches). The nominal diameter is different from the actual. According to the specified wall thickness, there are two kinds of welded pipes: ordinary steel pipes and thickened steel pipes.
1) Galvanized steel pipe: To improve the performance of steel pipes, general steel pipes (black pipes) are galvanized. Galvanized steel pipes are divided into two types: hot-dip galvanizing and electric steel zinc. Hot-dip galvanizing has a thick zinc layer and electro-galvanizing has a low cost.
2) Oxygen-blowing welded pipe: used as oxygen-blowing pipe for steelmaking. Generally, small diameter welded steel pipe is used, with eight specifications ranging from 3/8 inch to 2 inch. Made of 08, 10, 15, 20, or Q195-Q235 steel strip. To prevent corrosion, some are aluminized.
3) Wire casing: It is also an ordinary carbon steel electric welded steel pipe. It is used in concrete and various structural power distribution projects. The commonly used nominal diameter is from 13-76mm. The wire sleeve has a thin wall and is mostly used after being coated or galvanized, requiring a cold bending test.
4) Metric welded pipes: specifications are in the form of seamless pipes, welded steel pipes expressed in outer diameter * wall thickness in millimeters, welded with a tropical or cold zone of ordinary carbon steel, carbon steel or general low alloy steel, or with tropical welding Then it is made by cold drawing method. Metric welded pipes are divided into general-purpose and thin-walled pipes. They are generally used as structural parts, such as transmission shafts, or to transport fluids. Thin-walled pipes are used to produce furniture, lamps, etc. The strength and bending test of the steel pipe must be ensured.
5) Idler pipe: Electrically welded steel pipe used for belt conveyor idlers, generally made of Q215, Q235A, B steel, and 20 steel, with a diameter of 63.5-219.0mm. There are requirements for the curvature of the pipe, the end face to be perpendicular to the center line, and the ovality. Generally, water pressure and flattening tests are performed.
6) Transformer tube: used to manufacture transformer heat pipes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending, and hydraulic testing. Steel pipes are delivered in fixed lengths or multiple lengths, and there are requirements for the bending of the steel pipes.
7) Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, hollow rubber steel pipes for doors and windows welded from ordinary carbon structural steel and 16Mn and other steel strips. They are mainly used as agricultural machinery components, steel windows and doors, etc.
8) Electrically welded thin-walled tubes: mainly used to make furniture, toys, lamps, etc. In recent years, thin-walled tubes made of stainless steel strips have been widely used in furniture, decoration, fences, etc.
9) Spiral welded pipe: It is made by rolling low-carbon carbon structural steel or low-alloy structural steel strips into a pipe blank according to the angle of the spiral (called the forming angle), and then welding the pipe seams. It can be made of narrow The strip steel produces large diameter steel pipes. Spiral welded pipes are mainly used for oil and gas transportation pipelines, and their specifications are expressed by outer diameter * wall thickness. Spiral welded pipes are either single-sided or double-sided. Welded pipes should ensure that the hydraulic pressure test, tensile strength, and cold bending performance of the weld meet the regulations.
Post time: Jan-15-2024