Simple and Efficient Production Mode —— Brief Introduction of Manufacturing Technology of Straight-seam Steel Pipe

Straight-seam steel pipes are often used in the construction of tap water industry and petrochemical industry. It is a kind of steel pipe whose weld is parallel to the longitudinal direction of the steel pipe. Usually divided into metric welded steel pipes, welded thin-walled pipes, transformer cooling oil pipes, etc. The production process of straight welded pipe is simple, with high production efficiency, low cost and rapid development. Compared with spiral welded pipe, it has the advantage of fast production speed. The following small series will introduce you to the manufacturing process and related information of straight welded steel pipes.

1. What is a straight welded steel pipe?

Straight steel pipe English (straight steel? General welded pipe: General welded pipe is used for conveying low-pressure fluid. Made of Q 195, Q2 15A, Q235A steel and Q235B ordinary carbon? . Easy-to-weld mild steel 03 17 standard model 60 12 and steel mother 755 can also be used. Steel pipes have to undergo water pressure, bending, flattening and other experiments, which have certain requirements for surface quality. Usually the delivery length is 4- 10m, and it is often required to deliver according to the length (or double the length). The specifications of welded pipes are expressed in nominal caliber (millimeters or inches). The nominal caliber is different from the actual situation. Welded pipes can be divided into ordinary steel pipes and thickened steel pipes according to the specified wall thickness, and steel pipes can be divided into threaded and non-threaded pipes according to the pipe end form.

Submerged arc welding technology is adopted for longitudinal steel pipes, including filling welding and particle shielded flux submerged arc welding. The production diameter can reach 1500mm, LSAW is the abbreviation of submerged arc welding longitudinal steel pipe, and the production processes of submerged arc welding longitudinal steel pipe include JCOE forming process and coil submerged arc welding process. When the diameter is large, it may be rolled with two steel plates, which will form a double weld phenomenon. Can implement the standard GB/T309 1-2008 low-pressure fluid steel pipe production standard GB/T971.1-2? -1997 standards for the production and use of oil and gas steel pipes, and can the American API be implemented? 5L？ Standard shall be implemented for pipeline steel pipes. Material: Q195A-Q345E; 245Rq 345 QA-D； l245-L485； X42-X70. The main bearing parameters are 2ST/T? S is the yield strength and t is the wall thickness. Submerged arc welding has been developed to double-wire submerged arc welding and multi-wire submerged arc welding, and the efficiency has been further improved.

Second, the production process of straight seam steel pipe

Straight-seam steel pipes can be divided into high-frequency straight-seam steel pipes and submerged arc welded straight-seam steel pipes according to the production process. Submerged arc welded straight seam steel pipes are divided into UOE steel pipes, RBE steel pipes and JCOE steel pipes according to their forming methods. The following introduces the most common forming processes of high frequency straight seam steel pipe and submerged arc welded straight seam steel pipe.

Submerged arc welding process

1.？ Steel plate probe: after the steel plate used for manufacturing large-diameter submerged arc welded straight seam steel pipe enters the production line, the whole plate is detected by ultrasonic wave;

2.？ Edge milling: milling the two edges of the steel plate on both sides with an edge milling machine to achieve the required plate width, plate edge parallelism and groove shape;

3.？ Pre-bending edge: pre-bending the edge of the plate with a pre-bending machine to make the edge of the plate have the required curvature;

4.？ Forming: First, half of the pre-bent steel plate is pressed into a "J" shape on the JCO forming machine through multiple processes, then the other half of the steel plate is bent into a "C" shape, and finally an "O" shape with an opening is formed.

5.？ Pre-welding: seam welding and continuous welding of the formed straight seam welded steel pipe by gas shielded welding (MAG);

6.？ Internal welding: longitudinal multi-wire submerged arc welding (up to four wires) is adopted for the inside of straight seam welded steel pipe;

7.？ External welding: longitudinal multi-wire submerged arc welding is used to weld on the outer side of longitudinal submerged arc welded steel pipe;

8.？ Ultrasonic flaw detection ⅰ: carry out 100% flaw detection on the internal and external welds of straight welded steel pipes and the parent metal on both sides of the welds;

9.？ X-ray inspection ⅰ: the internal and external welds are inspected by 100% X-ray industrial television, and the image processing system is adopted to ensure the flaw detection sensitivity;

10.？ Expanding diameter: expanding the full length of submerged arc welded straight seam steel pipe to improve the dimensional accuracy of steel pipe and improve the internal stress distribution of steel pipe;

1 1.？ Hydrostatic test: check the expanded steel pipes one by one on the hydrostatic testing machine to ensure that the steel pipes meet the test pressure required by the standard, with automatic recording and storage functions;

12.？ Chamfering: the qualified steel pipe is processed at the end to reach the required pipe end groove size;

13.？ Ultrasonic inspection Ⅱ: Ultrasonic inspection shall be repeated one by one to check the possible defects of straight welded steel pipes after expanding and water pressure;

14.？ X-ray inspection 2: X-ray industrial television inspection and welding seam shooting of the steel pipe after expanding and hydrostatic test;

15.？ Magnetic particle inspection of pipe end: this inspection aims to find pipe end defects;

16.？ Anti-corrosion coating: qualified steel pipes should be coated with anti-corrosion coating according to user's requirements.

Three, the use of straight seam steel pipe

Straight-seam steel pipes are mainly used in tap water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation and urban construction. Used for liquid transportation: water supply and drainage. Used for gas transportation: gas, steam, liquefied petroleum gas. Used for structure: used for piling pipes and bridges; Pipes for docks, roads, building structures, etc.

What is the production process of straight seam steel pipe bending?

What is an elbow?

Bend pipes are bent with a complete set of bending dies. No matter what kind of mechanical equipment, most of them use elbow pipes, which are mainly used for oil, gas and infusion. , and plays a very important role in the aircraft and its engine.

Elbows can bend various contours.

Almost all sections of aluminum, steel, stainless steel, copper and other metal profiles and pipes (spiral pipes, straight-seam steel pipes, seamless pipes) can be bent.

The bending quality of elbow pipe is good, and the material after spraying, electroplating, polishing and wire drawing can be directly bent without damaging the surface of the material.

Material of reducing elbow:

There are cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals and plastics.

Connection with pipeline: direct welding (the most commonly used method), flange welding, hot melt connection, threaded connection, socket connection, etc.

According to the production process, it is divided into welding elbow, stamping elbow and casting elbow.

Elbow is a kind of connecting pipe fitting commonly used in pipeline installation, which is used to connect pipeline elbows.

Other names: 90-degree bend, right-angle bend

Use; Used for two pipes with the same or different nominal diameters to make the pipes turn at a certain angle.

Classification of elbows:

1, carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon, PPC, etc. 2. According to the manufacturing method, it can be divided into pushing, pressing, forging and casting.

3. According to the manufacturing standard, it can be divided into national standard, electric standard, water standard, American standard, German standard, Japanese standard and Russian standard.

4. According to its real radius of curvature, it can be divided into long radius elbow and short radius elbow. Long-radius elbow refers to the outside diameter of the pipe with a radius of curvature equal to 1.5 times, that is, r =1.5d. short radius elbow refers to the fact that its real radius of curvature is equal to the outside diameter of the pipe, that is, R= 1.0D(D is the straight work of the elbow and r is the real radius of curvature).

5. According to the pressure classification, there are about seventeen kinds, which are the same as American pipeline standards, including: Sch5, Sch 10s, SCH10s, STD, Sch60, Sch80s, Sch 100, Sch 120 and SCH/20.

After reading the above introduction, I think everyone will know something about the manufacturing technology of straight welded steel pipes. The application of straight seam steel pipe in the industry is obvious to all, and its wide application must be because of its unique advantages. Its production process is simple, production efficiency is high, and it has a wide range of uses. Here's a brief introduction to straight-seam steel pipes. Want to know more, please continue to pay attention to Tuba rabbit decoration!