The development of steel pipe production technology began with the rise and development of bicycle manufacturing industry. In the early nineteenth century, petroleum industry effectively promoted the development of varieties and production of steel pipe industry through the development of ships, boilers, aircraft manufacturing, post-World War II thermal power boiler manufacturing, chemical industry, oil and gas drilling and transportation. Quantity and quality.

　　鋼管不僅用于輸送流體和粉狀固體、交換熱能、制造機械零件和容器，而且是一種經濟適用的鋼材。采用鋼管制造結構網架、支柱和機械支架，可減輕重量，節約金屬20 ~ 40%，可實現工廠機械化施工。利用鋼管制造公路橋梁，不僅可以節約鋼材，簡化施工，而且大大減少了保護層面積，節約了投資和維護成本。

　　Steel pipe is not only used for conveying fluids and powder solids, exchanging heat energy, manufacturing mechanical parts and containers, but also an economical and applicable steel. The steel pipe is used to manufacture the structure net frame, pillar and mechanical support, which can reduce the weight and save 20 - 40% of the metal, thus realizing the mechanized construction of the factory. Making highway bridges with steel pipes can not only save steel and simplify construction, but also greatly reduce the area of protection layer and save investment and maintenance costs.

　　1. 假鋼管容易折疊。

　　1. False steel pipe is easy to fold.

　　折疊是在鋼管表面形成的各種折線。這種缺陷往往貫穿整個產品的縱向。折疊的原因是由于假冒偽劣廠家追求率，壓下量大，生產出的耳朵，下次滾壓上生產的折疊，折疊后的產品彎曲后會開裂，鋼材的強度下降。

　　Folding is a variety of folding lines formed on the surface of steel pipe. This kind of defect often runs through the longitudinal of the whole product. The reason for folding is that fake and inferior manufacturers pursue high efficiency, large reduction, the ears produced, folding on the next rolling, the folded products will crack after bending, and the strength of steel decreases.

　　2. 假鋼管的外表往往有麻子。

　　2. The appearance of false steel pipe is often pockmarked.

　　麻點表面是軋輥溝槽磨損嚴重引起的鋼表面不規則的不均勻缺陷。由于劣質鋼管生產企業為了追求利潤，經常出現軋制坡口軋制超標的情況。

　　The pitted surface is an irregular and uneven defect on the surface of steel caused by serious groove wear of rolls. In order to pursue profits, the production enterprises of inferior steel tubes often have the situation that the groove rolling exceeds the standard.

　　3.假鋼管表面容易產生疤痕。

　　3. The surface of false steel pipe is prone to scar.

　　有兩個原因:(1)。劣質鋼管材料不均勻，雜質較多。(2).偽劣材料生產廠家生產的導衛設備簡單，容易粘鋼，這些雜質咬人軋輥后容易產生疤痕。

　　There are two reasons: (1). The material of inferior steel pipe is not uniform and there are many impurities. (2) The guide equipment produced by the manufacturers of fake and inferior materials is simple and easy to stick to steel. These impurities bite the roll and easily cause scars.

　　4. 假材料表面容易產生裂紋，其原因是其坯料是土坯、土坯氣孔、土坯在冷卻時產生的過大

　　4. Cracks are easy to occur on the surface of false material because the billet is too large when the billet is cooled.

　　在加工過程中產生熱應力，產生裂紋，軋制后產生裂紋。

　　Thermal stress and cracks occur during the process of processing, and cracks occur after rolling.

　　5. 假鋼管容易劃傷，原因是假鋼管廠家設備簡單，容易產生毛刺，劃傷鋼材表面。深度劃傷會降低鋼的強度。

　　5. False steel pipe is easy to scratch, because the fake steel pipe manufacturer has simple equipment, easy to produce burrs, scratch the steel surface. Deep scratches reduce the strength of steel.

　　6. 假鋼管無金屬光澤，呈淡紅色或類似生鐵的顏色，原因有兩點二，其坯料為土坯。2、劣質材料軋制溫度不達標，其鋼材溫度是目測的，所以不能按照奧氏體區規定軋制，鋼材的性能自然不能達到標準。

　　6. Pseudo-steel pipe has no metallic luster and is light red or similar to pig iron. There are two reasons for this. Its blank is adobe. 2. The rolling temperature of inferior materials is not up to the standard, and the temperature of steel is visually measured, so it can not be rolled in accordance with the provisions of austenite zone, so the properties of steel can not meet the standard naturally.

　　7. 假的單杠鋼管是薄和低,經常出現填不滿的現象,原因是制造商為了達到大負公差,成品前幾個壓力體積偏大,小鐵,洞填不滿。

　　7. The fake horizontal bar steel pipe is thin and low, and it is often unsatisfactory to fill. The reason is that in order to achieve large negative tolerance, the manufacturer has large pressure volume in the first few parts of the finished product, small iron and hole filling are unsatisfactory.

　　8. 假的部分鋼管橢圓,原因是廠家為了節省材料,成品卷第二卷之前壓力很大,這種鋼筋的強度大大降低,而且也不符合鋼筋尺寸標準。

　　8. False part of steel tube ellipse, because the manufacturer in order to save material, finished volume before the second volume of the pressure is very high, the strength of this steel bar is greatly reduced, but also does not meet the steel bar size standards.

　　9. 鋼的成分是均勻的,冷剪機的噸位高,切割頭的端面光滑整潔,偽劣材料由于材料質量差,切削頭的端面經常有肉的現象,也就是說,不均勻,沒有金屬光澤。而且由于劣質材料廠家產品割頭少，頭尾會出現大耳子。

　　9. The composition of high-quality steel is uniform, the tonnage of cold shear is high, the end face of cutting head is smooth and tidy, and the fake and inferior materials often have meat on the end face of cutting head because of poor material quality, that is to say, it is not uniform and has no metallic luster. And because the products of inferior material manufacturers cut little, big ears will appear at the head and tail.

　　10. 假鋼管材料含有大量雜質，鋼的密度小，尺寸超差嚴重，所以在沒有游標卡尺的情況下，可以稱重檢查。鋼筋20,例如,大負公差標準規定的5%,規模9米的單一的理論重量是120公斤,應該是小的重量:120 X (l - 5%) = 114公斤,114公斤稱出的重量比小單,是偽劣鋼鐵,原因是它是負公差超過5%。一般來說，積分比例量的效果較好，主要考慮累積誤差問題和概率論。

　　10. Pseudo-steel pipe material contains a lot of impurities, the density of steel is small, and the dimension of the steel is excessive, so in the absence of vernier calipers, it can be weighed and checked. Reinforcement 20, for example, 5% of the national standard for maximum negative tolerance and 120 kg of single theoretical weight of 9 meters should be the smallest weight: 120 X (l - 5%) = 114 kg. The weight of 114 kg is smaller than that of single steel, which is fake and inferior because it has a negative tolerance of more than 5%. Generally speaking, the effect of integral proportion is better, mainly considering the cumulative error problem and probability theory.