What are the methods of identification of shoddy steel pipe?

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The shoddy steel pipe identification methods
     Shoddy steel pipe prone to folding. Folding steel pipe formed on the surface of various polyline, this defect is often longitudinall y throughout the entire product. Generate a folded reason is the the shoddy manufacturers to pursue high efficiency, the amount of reduction is too large, resulting in the ears, generated under a rolling folding, the folded products after bending will crack, a large decline in the strength of steel.
     2. The shoddy steel pipe appearance often pockmarked face. Ma surface is due to the steel surface irregularities uneven groove wear and tear caused by serious defects. Since the shoddy steel pipe manufacturers to the pursuit of profit, often the most excessive groove rolling. 3. The shoddy steel pipe surface is easy to produce scarring. There are two reasons: (1). Uneven the shoddy steel pipe material impurities. (2). Shabby, shoddy material manufacturers to guide and guard the equipment easy to stick easy to produce steel, of these impurities bite roll scarring.stainless steel clamps
     4. The inferior surface of the sheet is easy to produce cracks, because it dough adobe adobe many pores, the adobe due to thermal stress in the cooling process, resulting in cracks, after after rolling there crack.
     5. The shoddy steel pipe easily scratched due to shoddy steel pipe equipment is very easy to produce glitch scratch the surface of steel. The depth of scratches reduces the strength of steel.
     6. Shoddy steel pipe without metallic luster, pale red or similar color of the pig iron, because there are two two it blank is adobe. 2, non-standard the shoddy rolling temperature, the temperature of the steel is by visual observation, so that can not be carried out according to the provisions of the austenitic region of rolling steel performance standards naturally not.
     7. Thin and low, the shoddy steel pipe cross ribs often sufficient dissatisfaction with the phenomenon, because the manufacturers for large negative tolerance, finished the previous lane reduction is too large, iron-type small, pass sufficient dissatisfaction.Stainl ess steel flange
     8. The shoddy oval cross section of the steel pipe, because manufacturers in order to save material, finished roll two reduction is too large, the strength of this steel is greatly decreased, and does not conform to the standard of rebar Dimensions. 9. Uniform composition of the high-quality steel, cold shear tonnage, smooth and neat end face of the cutting head, shoddy material material difference, the end face of the cutting head, there are often off the meat of the phenomenon that is uneven and non-metallic luster. And because of shoddy materials manufacturers cutting head, the head and tail big ears.
     10. Shoddy steel material containing impurities, the density of steel is too small, and the size serious ultra-poor, so in the case of without a vernier caliper, were weighed it checked. For example, the rebar 20, the national standards set forth maximum negative tolerance of 5% Le ngth 9M single theoretical weight of 120 kg minimum weight should be: 120 X (l-5%) = 114 kilograms of weighing out the actual weight of more than 114 kg single small, shoddy steel because it is more than 5% negative tolerance. In general, the whole proportionate amount would be better, mainly taking into account the cumulative error probability theory this problem.
     11. The shoddy steel pipe diameter size fluctuations because; l, steel temperature instability of yin and yang face. 2, the composition of the steel is uneven. 3, poorly equipped, low-foundation strength, mill bouncing. Appear larger changes in the same week, reinforced Unevenness of fracture.steel pipe fittings