How to Maintain Alloy Steel Pipe?

The time of issue:2014-7-15 8:35:14       Author:

Filler metal with an "L" specified, such as ER308L, offer low carbon content, the biggest it can help keep the corrosion resistance of low carbon stainless steel alloy. In the how to maintain alloy steel pipe application of high purity - food, drink, medicine - low carbon content is the key to keep corrosion resistance. Instead, filler metal with an "H" is specified for application needs greater strength of high carbon content, especially at high temperature. Filler metal with high silicon content, such as ER309LSi, improve liquidity of molten pool, increase sale, improve the speed and increase productivity. Series 309, filler metal is especially good at combining of stainless steel and superposition of different applications.

When welding stainless API steel pipe, it is also important to low tracking (or "tramp") choose filler metal elements. These are used as the filler metal raw material of residual elements. They include tin, antimony, arsenic, phosphorus and sulfur, and the effect on the corrosion resistance is strong. Sensitization is a major cause of the corrosion loss, and chemical properties of the substrate material and filler metal, and the temperature in the weld are cooling. Chromium trioxide is stainless steel how to maintain alloy steel pipe "stainless" layer. If the increase in carbon content of welding seam and heat affected zone nearby, it formed chromium carbide, chromium occupied it, in order to prevent the formation of chromium oxide. This, in turn, makes the API steel pipe corrosion, otherwise will not have the desired corrosion resistance.

Sensitization to have hit three main ways: the first is to use low-carbon alkali and filler metal, in order to reduce or eliminate the welding application of carbon. This approach, however, how to maintain alloy steel pipe is not always feasible carbon is an important composition of alloy in some applications. It is to try to reduce the time of welding seam and heat affected zone temperature is helpful to sensitization. The range will depend on whom you ask, but a common consensus in API steel pipe range - between 500 and 500 degrees Celsius. Short medium temperature area, namely the cumulative cost less time from welding thermal damage, are attached to the welding procedure and because of that, it is important to determine the maximum interlayer temperature. In multi-channel application goal should be to use as few passing, lowest in welding heat input, as far as possible in order to realize the faster cooling.

The third is the use of filler metal with special alloy API steel pipe composition, in order to prevent the formation of chromium carbide. For example, titanium and niobium can be fusion to the filler metal, and helps to prevent the reaction between chromium and carbon. These elements also influence on strength and toughness, limits is a useful application. They also did not provide any benefits of regional furthest distance heat affected zone of the weld.

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