Method for Identifying the Inferiority of Seamless Steel Pipes

Aug 25


Marine Lee

Marine Lee

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Do you know how to identify the inferiority of steel pipes?


1. Fake and inferior seamless steel pipes are prone to folding.

Folding is a variety of fold lines formed on the surface of a seamless steel pipe that tends to extend throughout the longitudinal direction of the product. The reason for the folding is that the inferior manufacturer pursues high efficiency,Method for Identifying the Inferiority of Seamless Steel Pipes Articles the amount of pressing is too large, and the ear is generated, and the next rolling causes folding, and the folded product is cracked after bending, and the strength of the steel is lowered.

2. The appearance of fake seamless steel pipes often has pockmarks.

The pockmark is a defect caused by the irregularity of the surface of the seamless steel due to the serious wear of the groove. Due to the pursuit of profit by shoddy steel pipe manufacturers, the most frequent rolling mill rolling is exceeded.

3. The surface of the fake seamless steel pipe is prone to scarring.

There are two reasons for this: (1) The material of the fake steel pipe is uneven and has many impurities. (2) The fake inferior material manufacturer's guiding equipment is simple, easy to stick steel, after these impurities roll, easy to produce scars.

4. The surface of the fake inferior material is prone to cracks because the billet is adobe, the adobe has many pores, and the adobe is cracked by the action of thermal stress during the cooling process, and there is crack after rolling.

5. Fake and inferior seamless steel pipes are easy to scratch, because the equipment of the fake and inferior steel pipe manufacturers is simple, easy to produce burrs and scratch the surface of the steel. Deep scratches reduce the strength of the steel.

6. The fake steel tube has no metallic luster and is light red or similar to pig iron. There are two reasons for this: 1. Its billet is adobe. 2, the temperature of the fake inferior material rolling is not standard, their steel temperature is measured by visual inspection, so that the rolling can not be carried out according to the specified austenite region, the performance of the steel naturally cannot meet the standard.

7. The cross-fabricity of the inferior steel pipe is thin and low, and the phenomenon of filling and dissatisfaction often occurs. The reason is that the manufacturer has reached a large negative tolerance, the amount of 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.

8. The cross section of the inferior steel pipe is elliptical. The reason is that 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 meet the standard of the rebar size. .

9. The composition of high-quality steel is uniform, the tonnage of the cold-shearing machine is high, and the end face of the cutting head is smooth and tidy. However, due to poor material, the surface 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.

10. The inner diameter of the inferior steel pipe fluctuates greatly because of the reason; l, the steel temperature is unstable and there is a yin and yang surface. 2. The composition of steel is not uniform. 3. Due to the simplistic equipment, the foundation strength is low, and the rolling mill has a large bounce. There will be a large change in the same week, and such a steel bar is unevenly stressed and easily broken.

11. The trademarks and printing of quality pipes are relatively standardized.

12. Three steel pipes with a diameter of 16 or more, the spacing between the two trademarks is above IM.

13. The longitudinal reinforcement of the counterfeit steel rebar is often wavy.

14. The fake steel pipe manufacturers have loose packaging and elliptical sides because they do not have driving.