Steel pipe is used to convey fluids and powdery solids, exchange heat, make machine parts and containers, and is also an economical steel.Steel pipes can be divided into two categories according to the production method: seamless steel pipe and seamed steel pipe, seamed steel pipe sub-straight seam steel pipe and spiral seam welded pipe two kinds.
American Standard Size
The INOXCN GROUP CORPORATION’s sanitary pipe are widely used in pharmaceuticals, food, nuclear power, aviation, petroleum, chemicals, machinery, electric power, machinery and automobiles.
How to identify good and bad pipes：
1. Shoddy steel pipe is prone to folding.
Folding is the formation of a variety of steel tube surface fold line, this defect often runs through the entire longitudinal product. The reason for the folding is due to the shoddy manufacturers in pursuit of high efficiency, pressure under a large amount of partial, resulting in ears, the next rolling will produce folding, folding of the product after bending will crack, the steel strength of the big reduction.
2. Shoddy steel pipe appearance often have a pitting surface phenomenon.
Pitting surface is due to serious wear and tear caused by the rolling groove irregular rugged steel surface defects. As a result of shoddy steel pipe manufacturers to the pursuit of profits, often the most superlative rolling groove.
3. Shoddy steel pipe surface prone to scarring.
There are two reasons: (1). Shoddy steel pipe material is uneven and full of impurities. (2). Shoddy material manufacturers poor guide equipment, easy sticky steel, these impurities bite people after the rolls easy to produce scars.
4. Shoddy material surface prone to cracks, the reason is that its billet is billet, billet porosity, billet in the cooling over.
Process due to the role of thermal stress, resulting in cracks, after rolling there are cracks. 5.
5. Shoddy steel pipe is easy to scratch, the reason is that shoddy steel pipe manufacturers are poorly equipped, easy to produce burrs, scratching the surface of the steel. Depth of scratching to reduce the strength of steel.
6. Shoddy steel tube without metallic luster, was light red or similar pig iron color, for two reasons, two, its billet is billet.2, shoddy material rolling temperature is not standard, their steel temperature by visual inspection, so that can not be rolled according to the provisions of the austenitic region, the steel performance naturally can not meet the standard.
7. Shoddy steel pipe crossbar thin and low, often filled with the phenomenon of dissatisfaction, the reason is that manufacturers to achieve large negative tolerance, the first few finished products under the pressure of a large amount of small iron type, hole type filled with dissatisfaction.
8. Shoddy steel tube cross-section was oval, the reason is that manufacturers in order to save material, finished roll before the second pressure under the amount of large, the strength of this rebar greatly reduced, but also does not meet the standards of rebar shape size.
9 High-quality steel composition uniformity, cold shear tonnage of high, smooth and neat cutting head end, and shoddy material due to poor material, cutting head end often has the phenomenon of falling off the flesh, that is, uneven, and no metal luster. And as the shoddy material manufacturers product cut head less, the head and tail will appear big ears.
10. Shoddy steel pipe material contains impurities, the density of steel is small, and the size of the overlap is serious, so in the absence of vernier calipers, it can be weighed to check. For example, for rebar 20, the national standard specifies that the maximum negative tolerance of 5%, set the ruler 9M when its single theoretical weight of 120 kg, its minimum weight should be: 120X (l-5%) = 114 kg, weighing out the actual weight of a single root than 114 kg small, is shoddy steel, the reason is that it negative tolerance of more than 5%. Generally speaking, the whole-phase weighing effect will be better, mainly taking into account the cumulative error and probability theory of this problem.
11. Shoddy steel pipe inner diameter size fluctuations are large, the reason is; l, steel temperature instability has yin and yang surface. 2, the composition of the steel is not uniform. 3, due to poor equipment, low foundation strength, rolling mill bounces. There will be a large variation in the same week, so that the uneven force of the steel is prone to fracture.
12.The trademark and printing of high-quality pipes are more standardized.
13. Three steel pipe diameter 16 or more large threads, the distance between the two trademarks are more than IM.
14. Shoddy steel rebar longitudinal tendons are often wavy.
15. Shoddy steel pipe manufacturers are more loosely packed because they have no rows. The sides are oval in shape.
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