Extrusion Production Process of Precision Seamless Steel Pipe

Precision seamless steel tubes with conventional technology for the furnace + ESR -> forging or forging billet and rolling way. Product shape round bar, square flat and forgings. Then steam turbine plant for further processing, but the processing process more special shape, metal utilization after processing about 30%. To squeeze mode after production, will have the following advantages:

1, Precision seamless steel tubes in the best state of stress in the hot extrusion process, reducing the product of internal defects.

2, Easy to implement diverse cross-sectional shape, adapt more variety, small batch production.

3, In each direction of performance uniformity.

The main way to produce extrusion process: EAF + ESR -> forging or rolling cogging -> induction heating -> Extrusion -> annealing.

Extrusion and forging, rolling approach is the difference between:

1, Precision seamless extrusion heating temperatures than forging, rolling production is higher 30-60 ℃;

2, Deformation, high speed (deformed steel requires only 2-4S).

3, Multi-step, high metal consumption.

Right Way to Save Spiral Pipe

Proper way to preserve spiral pipe

1) Storage space spiral steel pipe products or warehouse, should be selected in clean, smooth

drainage area, away from harmful gases or dust in factories and mines. The presence on the ground to clear the weeds and all the debris, keeping a clean steel

2) In a warehouse not with acid, alkali, salt, cement, steel and other aggressive materials stacked together. Different varieties of steel should be stacked separately, to prevent confusion, to prevent contact corrosion

3) Large steel, rail, steel disgrace, large diameter steel pipe, forgings, etc., may open dumps

4) Small and medium steel, wire rod, rebar, medium diameter steel pipe, steel wire and wire rope, etc., can be expected in a well-ventilated storage shed, but it must be the underlying thatch

5) Some small steel, sheet, strip, silicon, or thin-walled small-diameter steel pipes, all kinds of cold-rolled, cold-drawn steel products and high prices, corrosive metal products, can be stored for storage

6) A warehouse should be based on selected geographical conditions, the general ordinary enclosed warehouse, that is the roof with walls, doors and windows tight, with the Treasury ventilation device

7) Requires the Treasury sunny attention to ventilation, rain close attention to moisture, keep the appropriate storage environment

The Advantages of Rectangular Tube

Steel tube is used as a structural element in buildings, bridges and other structures, and in a wide variety of manufactured products. It's produced in round, square and rectangular shapes in a broad range of sizes and gauges. 

Rectangular tubing has many benefits: aesthetic appeal, high strength-to-weight ratios, uniform strength, cost effectiveness and recyclability. 

The advantages for designers, specifies, fabricators and end users are outlined on the 

• Rectangular tubing has greater strength-to-weight ratios. So, with Rectangular tubing you need less steel, by weight, to do the job. And less weight equals less cost 

• Excellent compression and support characteristics and superior resistance make Rectangular tubes particularly well suited to all types of column applications 

• Rectangular steel tube is made from steel, one of the world’s most recyclable and recycled materials 

• Torsional strength makes steel rectangular tube an excellent choice for bear resistant and consistent. 

Rectangular tube is fire resistant and does not warp, twist, split, swell or shrink. It resists dry rot and mildew, termites and carpenter ants. For increased fire resistance, the exterior of the product may be sprayed with a fire retardant material. The interior can be filled with concrete. Tube rectangular can be readily bent, formed, punched, and drilled. New and improved methods to fasten Rectangular tubing to itself or to other materials are making its use simpler and fabrication faster. 

Common Defect Detection Method of Spiral Pipe

SSAW common defects magnetic particle testing or penetration testing. Spiral pipe magnetic particle testing or penetrant testing can be effectively found that surface cracks, folding, re-skin surface defects, hairline, pinholes. For ferromagnetic materials, magnetic particle testing method should be given priority, because of its high detection sensitivity; for non-ferromagnetic material, such as stainless steel spiral pipe, is used penetrant inspection method.

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Online austenitic steel spiral pipe, when the insulation is damaged or rain may have infiltrated the site, note that penetration testing to find stress corrosion cracking or pitting and other defects. However, magnetic particle or penetrant testing only on the outer surface of the pipe to detect internal defects in the surface of the powerless. The inner surface of the detector, especially crack type defect detection must be carried out by ultrasonic testing.

When the spiral pipe ends aside less resection margin, due to structural reasons detection device, spiral pipe ends head sometimes can not be effectively detected, and the end is the most likely site of the presence of cracks or other defects. If the spiral steel pipe ends there is potential for cracking tendency, weld heat affected during installation may also make potential crack. Therefore, it should be noted that after the detection of certain welded spiral steel area, to detect extended spiral steel tip defects.

How to Improve the Accuracy of Precision Steel Pipe Wall Thickness

Wall thickness precision steel pipe production control is a difficult process and improve the accuracy of precision steel wall thickness are mainly the following aspects:

1, heating pipes, heating should be uniform, rapid lifting ban temperature. Each heating and

cooling, in order to maintain stability.

2, centering rollers, opening the same size centering rollers determine the installation is in place, embrace the central core volume adjustments related to the opening angle and various actions.

3, rolling centerline, the centerline of the car to ensure that rolling consistent with the centerline of the hole puncher avoid scrolling up and down "the tube to maintain a straight line.

4, rolling tool for head and other rolling tool wear should be promptly replaced.

5, rolling tool installation, the central leadership must ensure that the centerline of the centerline distance and rolling guide rollers perforated, which is equal to the distance from the upper and lower rollers are approximately equal.

6, perforation ram ram perforation usually selected outer diameter Φ108mm-Φ114mm, wall thickness and wall thickness requirements ≥25mm uniform thick-walled tube.

7, the mandrel mill, a mandrel to choose and the thick walled precision steel processing, the smaller size of the mandrel can be used in place of solid billet. Thickness uniformity walled tubes and solid billets, can make the probability of a significant reduction in the mandrel bending deformation, can effectively improve the precision steel tube wall thickness.

8, precision mandrel, the mandrel slenderness relatively large, generally using the first car and then hit the outside diameter of groove weld, directly open long or molding material. Mandrel outer precision control ± 0.1mm, straight mandrel deviation does not exceed 5mm. Welding, finishing insert a pin positioned between two sections of the mandrel, the total deviation to prevent the direct result of excessive welding.

9, process improvements, process improvement, prevent the intermediate precision steel pull thin wall thickness and increase exceeds the control range occurs.

The Difference Between Single Row and Integrated Scaffolding

(1) When the building of scaffolding outside the building facade along the line erection height is less than 15m, calculated as a single row of scaffolding; higher than 15m, calculated as a consolidated scaffolding. 

(2) the upper part of the wall outside the building line chooses 1.5m or more, according to the

top of the exterior wall outside the building line or uneven length times the total height of the outer scaffolding erection calculated area; the lower part of the wall in accordance with the vertical part retracts into the envelope projected area calculate according to the appropriate height of a single row of scaffolding itself.     

(3) lighting recessed portion open well: when mouth width (distance between the exterior structure) ≤3.5m, press the recessed portion exterior wall vertical projection area of ​​a single row of scaffolding, light wells mouth with or without connecting beam are calculated together with the external walls of the integrated scaffolding; when mouth width (distance between the exterior structure) 3.5m, press the recessed portion to the inside of the vertical projection area of ​​the external walls of integrated computing m2 scaffolding outside light wells mouth connecting beam, integrated computing and the exterior scaffolding together, without connecting beam does not count scaffolding.     

(4) When the stone masonry regardless of the external walls, height of more than 1.2m, integrated computing side scaffold; when the wall thickness is greater than 40cm, integrated computing side and one side of a single row of scaffolding. 

(5) large equipment base height of more than 2m, its base multiplied by height perimeter shape area (m2) to calculate a single row scaffolding.     

(6) roof daughter wall surface over the roof height 1.2m, according to the inner surface of the vertical projection area to calculate single row of scaffolding. 

Basic Knowledge of Welded Steel Pipe

Welded pipe is a common seen pipe which usually be used on fluid conveyance. Generally, it is defined to as the large diameter solder pipe, in accordance with the welding as a way for tube, the solder steel pipe consist spiral pipe and straight seam welding tube.

Based on the application, it can be divided into general welded pipe, galvanized welded tube, oxygen blowing metric pipe, welded tubes, wire casing, roller tube, deep well pump tubes, auto tube, transformer, electric soldering thin wall pipe, welded pipe and spiral welded tube.

Spiral welded pipe is the low carbon structural steel and low alloy structural steel strip according to certain helix Angle rolled into a tube billet, and then solder pipe joints made up, it can use a narrow strip in the production of large diameter steel tube, straight seam solder pipe is hot rolled plate after molding machine molding, roll deformation of steel coil for round cylinder, using frequent current skin effect and proximity effect or flux layer burning under the arc soldering, the tube billet is heated to melt, and fusion under certain extrusion effect, after the final cooling forming.

Welded tube is made of steel plate or steel strip after crimp forming, and then after welding. Divided into the form of the weld seam welded tube and spiral welded pipe, straight seam steel tube forming technique of common UOE forming process, JCOE steel pipe forming process.