Folding is a kind of broken line formed on the surface of the pipe, which often runs through the whole product.Causes of fold is due to the pursuit of the false and inferior, high efficiency, large reduction, handle, when the next rolling produce folding, folding products will be cracking after bending, strength of steel.
1.The appearance of the fake steel pipe often has the phenomenon of hemp.
The face is caused by the wear of the groove causing the uneven surface of the steel surface irregularity.Because fake steel tube manufacturer wants to pursue profit, often appear the groove rolling system exceeds standard.
2.The surface of the fake steel pipe is liable to scar.
There are two reasons for this: (1).Fake and inferior steel pipe material is not uniform, impurities.(2).Fake and inferior material manufacturer's guide equipment is simple, easy to adhere to steel, these impurities are easy to produce scar after rolling.
3.The surface of the fake and inferior material is prone to crack, because its billet is the adobe, the air hole is much, the adobe is cooling
Due to thermal stress in the process, cracks are created and cracks are found after rolling.
4.Fake and inferior steel pipe is easy to scrape, the reason is that the manufacturers of fake steel pipe are simple, easy to produce burrs, and scratch the surface of steel.Deep scratches reduce the strength of the steel.
5.The fake steel tube has no metallic luster, which is reddish or similar to the color of pig iron, for two reasons, its blank is the adobe.2. The temperature of the fake and inferior materials is not standard. The steel temperature of their steel is made through visual inspection. In this way, the austenitic region can not be rolled, and the performance of the steel can not meet the standard.
6.The horizontal bar of the fake steel pipe is thin and low, and it often appears to be a phenomenon of discontent. The reason is that the manufacturer has a large negative tolerance, the first few lines of the finished product are too large, the iron type is small, and the pore type is dissatisfied.
7.And inferior steel tube cross-section oval, because the factory in order to save material, the quantity of the finished product roll before 2 slants big, the strength of rebar is greatly decreased, but also do not conform to the standard of rebar shape size.
8.Cold shearing machine of high quality steel composition is uniform, high tonnage, cutting head end face smooth and neat, and shoddy material because the material is poor, cutting head end face often have meat, or uneven, and no metallic luster.And because the product of the manufacturer of fake and inferior products has less cutting head, the head tail will appear big ears.
9.Fake and inferior steel pipe material contains more impurities, the density of steel is small, and the size is very bad, so it can be checked by weighing it without vernier caliper.For rebar 20, for example, maximum minus tolerance specified in the national standard of 5%, scale of 9 m in the theory of single weight is 120 kg, it should be the smallest weight: 120 X (l - 5%) = 114 kg, 114 kg weigh out the weight of the single than small, is false and inferior steel, the reason is that it is negative tolerance more than 5%.Generally, the overall proportionality effect will be better, taking into account the cumulative error and probability theory.
10.The inner diameter of the fake steel tube has a large fluctuation, the reason is;L, steel temperature instability has the Yin and Yang noodles.2. The composition of steel is not uniform.3. Owing to the humble equipment, the foundation strength is low and the rolling mill is large.The occurrence of a large change in the same week, such reinforcement stress uneven and easy to produce fracture.
11.The quality control of the trademark and the printing of the specification.
12.The diameter of the three steel pipe is more than 16, and the spacing between the two trademarks is above IM.
13.The longitudinal veins of fake steel rebar are often wavy.
14.The fake steel pipe factory is packed relatively loose due to lack of driving.The sides are oval in shape.