The Trend of Welded Steel Pipe Industry

The time of issue:2014-9-12 8:53:53       Author:

This microstructure of welded steel pipe should undergo two steps of heat treatment that is followed by isothermal quenching at selected temperature. Temperature of welded steel pipe should be controlled by the carbon concentration in austenite while temperature of isothermal quenching lies in a higher range. After quenching, it takes one to three hours for the welded steel pipe castings to be cooled to room temperature. The choice of the welded steel pipe tempering time for given temperature is critical, because the process should stop.

Due to this reason, ferrite should be used to maximize before the carbides start to form. Except mixture of welded steel pipe ferrite and retained carbon will lead to some amount of welding forms. It appears mainly in low temperature as well as high strength ductile iron where high wear resistance is needed. The relative small amount can be tolerated in most of welded steel products. We must remember that isothermal quenching has been applied to welded steel pipe for many years and the heat treatment leads to a fine dispersion of carbide. The decrease of welded steel products reflects the trend of the automotive industry to produce cars with higher strength steel and the substitution of iron engine blocks and steel frames by aluminum.

Furthermore, the stock of welded steel pipe has significantly declined over the past decades according to a sensitivity analysis. This is largely because per capita saturation is robust with respect to the assumed lifetime distributions. On the other hand, the saturation levels of welded steel pipe strongly depend on the assumed lifetimes of the welded pipe products. The saturation phenomenon is independent of the lifetime assumptions because of the modest changes in welded steel pipe inputs. The data are assembled to generate our best estimate of the steel pipe cycle and they can also illustrate the significance of international trade. Net import and export flows may cross the system boundary and most iron units stem from the aggregate net imports of iron ore and raw steel parts.

New final welded steel pipe products may have the largest losses from discards of obsolete products to landfills. Blast furnace and steel slag can be calculated and welded steel products account for a significant portion of the steel products. The former is calculated by using the lifetime distribution model, whereas the latter is computed based on the mass balances and scrap processing. Compared with system definition, welded steel pipe imports and exports are aggregated to net trade flows. It should be added that in upper dispersed carbides welded steel products are located at the ferrite grain boundaries even though the dispersed carbides occupy interior ferrite.

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