steel tube pipe

8. Inferior steel oval-shaped cross section appear before, because the manufacturers in order to save materials and finished products before the two rollers of rolling reduction is too large, which greatly decreased the strength of steel, but steel does not conform to the standard dimensions.
9. Homogeneous high-quality steel, cold shear tonnage of high-cut head and face smooth and neat, and inferior material because the material is poor, cut the meat off the head and face often have the phenomenon that is uneven, and no metallic luster. And because of shoddy materials manufacturers products less cutting head, big ears will be sub-head and tail.alloy pipe

6. Inferior steel no metallic luster, pale red or similar color of pig iron, for two reasons Second, it is adobe blank. 2, inferior wood rolling temperature non-standard, their steel temperature is visual, so the region can not be required for rolling of austenitic steel performance standards can not be natural.carbon steel pipe
7. Inferior steel cross bars thin and low, often dissatisfied with the phenomenon of charge, because the manufacturers to achieve large negative tolerance, finished a few of pressure before the volume is too large, iron-type small, hole fully satisfied.

3. Inferior steel surface is easy to produce scarring.
There are two reasons: (1). Inferior steel material is uneven, impurities. (2). Shoddy materials manufacturers guide and guard equipment simple, easy to stick steel, these impurities after the roll bite is easy to produce scarring.
4. Shoddy material surface easy to crack, because it is blank adobe, adobe pores more adobe cooling off in the
Process due to thermal stresses, cracks, after rolling through the cracks there.carbon steel pipe
5. Inferior steel is easy to scratch, because the poorly equipped and inferior steel pipe manufacturers, easy to produce glitch, scratch the surface of steel. Deep scratches reduce the strength of steel.

1 shoddy steel prone to folding.
Fold is formed on the surface of steel pipe line, this defect often throughout the product vertical. Have folded due to shoddy manufacturers for high efficiency, the amount of pressure is too large, resulting in the ears, under the fold to produce a rolling, folding of the product after bending will crack, steel strength decreased.boiler tube
2. Ma shoddy steel exterior surface phenomena often.
Pock is due to severe wear and tear caused by steel rolling groove irregular uneven surface defects. As the inferior steel manufacturers to the pursuit of profit, most often excessive rolling rolling groove.

Steel not only for the transmission fluid and powdered solid, the exchange energy, manufacturing, machine parts and containers, it is an economical steel. Manufacture of building structure with steel grid, pillars and mechanical support, can reduce weight, save 20 to 40% of the metal and mechanical construction can achieve the factory. (Tianjin Pipe Company processing plant with a steel grid structure as the actual saving of steel up to 42.9%), with a steel road bridge will not only save manufacturing steel, to simplify construction, and protective layer coating can greatly reduce the area of ​​investment and maintenance cost savings . So, any other type of steel can not completely replace the pipe, but steel can replace part of the Sections and bars. Steel for national economic development and improve the quality of human life a great relationship, better than other steels.alloy pipe.

From international and domestic market, the seamless steel pipe (including OCTG) are greater than the existing production capacity needs. Therefore, future emphasis should be placed on the ability to give full play to existing units, the development of high-strength grade, high-combat damage, high resistance to corrosion of oil pipes, high pressure boiler tubes and cylinder pipe and other products. Also for the current state of China’s steel market to optimize the product structure of the content. This is to increase competitiveness in domestic and foreign products, expand market share in the key. That is, the domestic steel enterprises to improve the market competitiveness of domestic enterprises increases and the WTO’s mission and long-term success of development.boiler tube

The same year, consumption of large oil pipe about 91 million tons. Imported about 2.52 million tons. Inlet tube of total domestic consumption of about 70%, of which the inlet tube of total domestic consumption of 27.69%, oil imports account for about seamless steel pipe imports total about 70%. Oil pipe imported from Japan for more than half of total imports. China’s largest production base of oil casing , steel tube pipe

Currently, the world’s total steel production has more than 110 countries, more than 1850 companies under the 5100 production plants, which produce oil pipe 44 countries, more than 170 companies under more than 260 plants. In 2000, apparent consumption of seamless steel pipe China 4.18 million tons, of which the domestic supply of 3.821 million tons, accounting for 91.4% of total domestic demand. Imported 35.9 million tons, accounting for 8.59% of total domestic demand.steel tube pipe

(1) GB3087-82 “low and medium pressure boiler seamless steel pipe” requirement. Chemical test methods according to GB222-84 and GB223 “steel and alloy chemical analysis method” in the relevant parts.
(2) GB5310-95 “high-pressure boiler seamless steel pipe” requirement. Chemical test methods according to GB222-84 and the “steel and alloy chemical analysis method”, GB223 “steel and alloy chemical analysis method” in the relevant parts.alloy pipe
(3) import the chemical composition of boiler tube inspection according to the standards stipulated in the contract

2, according to the classification of cross-section shape
(1) simple cross-section steel – round steel, square steel tube, oval tube, triangle tube, hexagon steel, diamond steel, octagonal steel, semi-circular steel round, other
(2) complex section steel – equilateral hexagonal steel pipe, five plum-shaped steel tube pipe double convex, double concave steel, oval-shaped steel, conical steel pipe, corrugated steel pipe, steel case, other
3, classified according to thickness – thin-walled steel pipe, thick-walled steel pipe
4, classified by use – with a steel pipe, steel pipe thermal equipment, machinery and industrial steel, petroleum, geological drilling steel, container, steel, chemical, industrial pipe, special-purpose steel, the other 4 chemical testing