Company Dynamic

March 26, 2019

Characteristics for grade 20

     Grade :     20   ( 20 )       Substitute:   15, 25       Classification :   High quality structural carbon steel       Chemical composition in % for grade   20   ( 20 )   C Si Mn Ni S P Cr Cu As 0.17 – 0.24 0.17 – 0.37 0.35 – 0.65 max   0.3 max   0.04 max   0.035 max   0.25 max   0.3 max   0.08   Temperature of critical points for grade   20   ( 20 ).   Ac1 = 724 ,      Ac3(Acm) = 845 […]
January 8, 2019

How is the theoretical weight of spiral steel pipe calculated?

  The theoretical weight of steels is obtained by calculating nominal dimensions and density (which is called specific weight in the past). This is directly related with the steel length, the cross section area, and the allowable size deviation. Because of the allowable deviation in the process of manufacturing, the calculated theoretical weight is somehow different from the actual value, and the theoretical value is only for reference while estimating. The fundamental equation is as follows: Steel pipe single meter weight calculation (kg / m): W = (outer diameter – wall thickness) * wall thickness * 0.02466 = 2408 * 12 * 0.02466 […]
January 7, 2019

Corrosion Resistance of API 5L Pipeline Steel with Coating Protection

ABSTRACT The corrosion resistances of enamel-coated steel pipe in  3.5 wt% NaCl solution was evaluated and compared with those of epoxy-coated pipe using open-circuit potential, linear po- larization resistance, and electrochemical impedance spectros- copy tests. T-001c enamel slurry and GP2118 enamel powder were sprayed to steel pipe in wet and electrostatic processes, respectively. The phase composition and microstructures of the two enamels were characterized with x-ray diffraction and scanning electron microscopy (SEM). The surface roughness of enamels and their bond strength with steel substrates were quantified to understand coating quality. SEM images revealed that both types of enamel coatings have […]
January 4, 2019

Casing pipe application in high-temperature gas wells

In recent years, with the decreasing number of easily exploitable oil and gas wells, it has become necessary for oil and gas wells to go deeper on both underground and underwater. And, tubing and casing strings are subjected to higher temperature and higher pressure in these wells, which would probably cause casing failure or gas leakage in the high-pressure/high-temperature (HPHT) wells. Hence, more attention has been paid to wellbore integrity in oil and gas industry in recent years.1,2 The key factor of wellbore integrity is casing string connections, which are expected to provide both structural and leakage integrity under severe environment. […]
January 4, 2019

Properties of Galvanized Steel Pipe Welds

Properties of Galvanized Steel Pipe Welds Galvanizing has been used to protect iron and steel from rusting for over a hundred years in places as diverse as the wire rope used for the suspension cables on the Brooklyn Bridge to gutters on houses. Galvanizing is simply coating of zinc over steel. Like paint, galvanizing protects steel from rusting by forming a barrier between the steel and the environment, but galvanizing goes one giant step further than paint — it also provides electrochemical protection of the steel. Since zinc is electrochemically more reactive than steel, it oxidizes to protect the steel […]