Comparison of Common Steel Pipes and Welded Steel Pipe

The time of issue:2014-7-11 8:33:53       Author:

Once operators understand how to maintain stainless steel pipe, it will not only help to save a large sum of money while they preserve the pipes in the warehouse, but will also improve the overall satisfaction rate of the buyers of stainless steel pipe. Some engineers have compared the common steel pipes with welded steel pipe mostly from point view of their structure, the weight, scanning electron microscopy as well as the transmission electron microscopy. Some other parameters of the welded steel pipe are also used so that details concerning the preparation of the specimen for welded steel pipe observations will be given elsewhere.

It is not so difficult to understand how to maintain stainless steel pipe as long as we know the tricks. It is very easy to see that the welded steel pipe matrix consists of mixture of different kinds of ferrite and carbon stabilized austenite. In micrograph the gray needles of welded steel pipe ferrite are in general embedded in the white austenite matrix and the needles often form specific blocks. In fact, the micro structures of welded steel pipe are parallel to each other and the relative high tempering temperature prevents the false formation at the very beginning.

It is one of phases that will be formed when the low temperature tempering is applied in the welded steel pipe production. No other phases, like carbides are visible in micrograph even at magnification rate of more than one hundred times. In fact, it is almost impossible to be presented in terms of the micro structure since the welded steel pipe and the low alloy steel observed are made with conventional light microscopy. In other words, we may not have any chance to compare the tempered low alloy steel pipes with welded steel pipe. Nevertheless they can be presented and the results are comparable under light microscopy in spite of a much higher magnification rate.

No carbides are visible in the welded steel pipe and the morphology of welded steel pipe fracture surface is by no means obvious so that the characteristic dimples. It is typical for ductile welded steel pipe mode of fracture to be clear visible on the left side of micrograph and the depth of dimples is capable of reflecting the ductility of welded steel pipe material, which can be used to suggest that this ductile mode of fracture is caused by austenite. The right side of welded steel pipe is quite different since it is characterized with rather flat surfaces as well as cleavage plane made from ferrite. This mode of fracture surface morphology of the welded steel pipe confirms the complex micro structure that consists of ductile lattice austenite and less ductile ferrite.

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