The carbon steel pipe is closely related to human life and production activities. The production technology of the steel pipe industry not only develops rapidly, but also introduces new ones. Steel pipe production occupies an irreplaceable position in the iron and steel industry. The development of steel pipe production technology began with the rise of the bicycle manufacturing industry.
1. The cross-bar of the shoddy steel pipe is thin and low, and the phenomenon of unsatisfactory filling often occurs. The reason is that the manufacturer has to achieve large negative tolerances, the amount of reduction in the first few passes of the finished product is too large, the iron type is too small, and the hole type is not full.
2.The shoddy steel pipe is elliptical in cross-section because the manufacturer has to reduce the amount of material in front of the roll in order to save material. The strength of this rebar is greatly reduced, and it does not meet the standard for rebar size.
3.The composition of high-quality steel is even, the tonnage of the cold shears is high, and the end face of the cutting head is smooth and neat, and the inferiority of the material due to poor quality is often due to the phenomenon of falling meat on the end surface of the cutting head, ie unevenness and no metallic luster. Moreover, due to the lack of cut-to-size products from manufacturers of inferior and inferior products, big ears will appear at the head and tail.
4. The inferior steel pipe material contains many impurities, the density of the steel is small, and the size of the steel pipe is so bad that it can be weighed and checked without a vernier caliper. For example, for rebar 20, the national standard specifies a maximum negative tolerance of 5%. When the length is 9M, its single theoretical weight is 120 kg. Its minimum weight should be: 120X (l-5%) = 114 kg, Measuring the actual weight of a single root smaller than 114 kilograms is a counterfeit steel because it has a negative tolerance of more than 5%. In general, the phasing effect will be better, mainly considering cumulative error and probability theory.
5.The size of the internal diameter of the shoddy steel pipe fluctuates greatly. The reason is that: l. The temperature of the steel is unstable and there is a yin and yang surface.
6. the composition of steel is not uniform. 3, due to the simple equipment, low strength of the foundation, the mill bouncing. There will be a large change within the same week, so that the steel reinforcement is not easy to produce fracture.
7.The trademarks and logos of high-quality tubes are all more standardized. . In the case of large threads with a diameter of 16 or more, the distance between the two trademarks is more than IM.
8.Spurs of steel rebar are often wavy. 15. The shoddy steel pipe manufacturers have looser packing because they have no driving. The side is oval.
What are the precautions for storing seamless steel pipes?
1. Choose a suitable venue and warehouse; 2. Reasonable stacking, advanced first; 3. Packaging and protective layers of protective materials; 4. Keep warehouse clean and strengthen material maintenance.
Significance of Proximity Effect on the Production of High-frequency Longitudinal Welded Pipes
In addition to the skin effect, the proximity effect is another feature of current. When alternating currents of equal magnitude and opposite directions pass through two adjacent conductors, the current will flow through the adjacent inner surface layers of the two conductors, and when the two conductors pass When alternating currents of the same size and direction, the current will flow through the outer surface layers of the two conductors. The proximity effect of the current makes the current in the conductors further uneven. It is this unevenness that makes the high-frequency welded pipe(ERW).
Summary of Advantages and Disadvantages of High-Frequency Welded Pipe Forming Methods
Advantages and disadvantages of high-frequency welded pipe forming methods
