A steel pipe made of a single piece of metal with no seams on its surface is called a seamless steel pipe. According to the production method, the seamless steel pipe is divided into a hot rolled pipe, a cold rolled pipe, a cold drawn pipe, an extruded pipe, a top pipe, and the like. According to the shape of the section, the seamless steel tube is divided into two types: a circular shape and a special shape. The shaped tube has a plurality of complicated shapes such as a square shape, an elliptical shape, a triangular shape, a hexagonal shape, a melon shape, a star shape, and a winged tube. The maximum diameter is 650mm and the minimum diameter is 0.3mm. Depending on the application, there are thick-walled tubes and thin-walled tubes. Seamless steel pipes are mainly used for petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation.
How to identify the advantages and disadvantages of seamless steel pipe?
- The shoddy thick-walled seamless steel pipe is prone to folding. Folding is a variety of fold lines formed on the surface of thick-walled seamless steel tubes, which often extend throughout the longitudinal direction of the product. The reason for the folding is that the inferior manufacturer pursues high efficiency, the amount of pressing is too large, and the ear is produced. When the next rolling is performed, the folding occurs, and the folded product is cracked after bending, and the strength of the thick-walled seamless steel pipe is greatly reduced. .
- The surface of the shoddy and thick-walled seamless steel pipe often has a pockmark phenomenon. The pockmark is a defect caused by the irregular irregularity of the surface of the thick-walled seamless steel pipe due to the serious wear of the groove. Due to the pursuit of profit by shoddy and thick-walled seamless steel pipe manufacturers, the most frequent rolling mill rolling is exceeded.
- The shoddy thick-walled seamless steel pipe is easy to be scratched because the equipment of the fake inferior material manufacturer is simple, easy to produce burrs, and scratches the surface of the thick-walled seamless steel pipe. Deep scratches reduce the strength of thick-walled seamless steel tubes.
- The shoddy thick-walled seamless steel pipe has no metallic luster and is light red or similar to pig iron. The reason is two points. The blank is adobe. 2, the temperature of the fake inferior material rolling is not standard, their steel temperature is measured by visual inspection, so that it can not be rolled according to the specified austenite area, the performance of thick-walled seamless steel pipe can not meet the standard.
- The cross-fabricity of the thick-walled seamless steel pipe is thin and low, and there is often a phenomenon of dissatisfaction. The reason is that the manufacturer has to achieve a large negative tolerance, the reduction of the first few passes of the finished product is too large, the iron type is small, and the hole type is not full.
- The cross-section of the shoddy thick-walled seamless steel pipe is elliptical, because the manufacturer has to reduce the amount of the two rolls in front of the finished roll in order to save material. The strength of the rebar is greatly reduced, and it does not conform to the size of the rebar. Standard.Galvanized Steel Tube
- The quality of the high-quality thick-walled seamless steel pipe is uniform, the tonnage of the cold-shearing machine is high, the end face of the cutting head is smooth and tidy, and the fake inferior material is often poor in material, and the end face of the cutting head often has a phenomenon of falling meat, that is, unevenness and no metallic luster. . And because the fake inferior products manufacturers have fewer heads, big ears will appear at the head and tail.
- The surface of the counterfeit thick-walled seamless steel pipe is prone to scarring. There are two reasons for this: 1. The shoddy thick-walled seamless steel pipe is uneven in material and has many impurities. 2. The fake inferior material manufacturer’s guiding equipment is simple and easy to stick steel. These impurities are easy to cause crusting after biting the roller.
- The surface of the fake inferior material is prone to cracks because the billet is an adobe, and the adobe has many pores. The adobe is cracked by the action of thermal stress during the cooling process, and cracks occur after rolling.