With the increase in people's requirements for drinking water sanitation and safety, stainless steel water pipe has been widely used in public buildings and urban residential buildings. The occurrence of corrosion damage can be roughly divided into two categories: general corrosion and local corrosion. Corrosion usually refers to corrosion being evenly or unevenly distributed throughout the entire surface of a component. It is easy for people to notice this corrosion and it is easier to take countermeasures. Let’s take a look at the reasons for the corrosion of the surface of stainless steel pipes.
Thin-walled stainless steel pipe
Corrosion usually does not involve the entire surface of the stainless steel pipe, but only occurs inside or around the defect. This problem of local corrosion is generally pitting or crevice corrosion, and will corrosion to depth and breadth, but will not affect the surface of most students in the enterprise. Let’s first talk about the reasons for the corrosion of the surface of thin-walled stainless steel pipes.
1, dust
is often in dusty places when the production and processing enterprises are in production. The dust in these ambient air will continue to develop and fall on the surface of stainless steel thin-walled pipes. These dust can be washed away with water or alkaline solution. However, if the dirt is sticky, you should use the high pressure water gun to clean it.
2, floating iron powder or embedded in
on the surface of thin-walled stainless steel pipes, free iron will rust and corrode the pipes. So it must be cleared. Floating powder iron can usually be removed with dust. If some parts have strong adhesion, they must be treated with the embedded iron.
In addition to dust, there are many sources of surface iron, including cleaning with ordinary carbon steel wire brushes and shooting peening with sand, glass beads, or other abrasives previously used on ordinary carbon steel, low alloy steel or cast iron parts, or grinding the aforementioned non-stainless steel products near stainless steel parts and equipment. If no protective measures are taken for stainless steel during the process of unloading or hanging, the wire rope, spreader and iron on the countertop can easily be embedded or stained.
3, scratch
In order to prevent the accumulation of process lubricants, products or dirt, it is necessary to mechanically clean the rough surfaces such as scratches of stainless steel thin-walled tubes to make them smooth.
4, heat tempering color and other oxide layers
During welding or grinding, stainless steel pipes will be heated to a certain degree of high temperature in the air. At this time, chromium oxide thermal tempering color will appear on both sides of the weld, the lower surface and the bottom of the weld. Thermal tempered color is thinner than the oxidation protective film and is obviously visible. This color is determined by thickness and will appear in rainbow, blue, purple to pale yellow and brown. Thicker oxide is usually black.
This is because we are staying in high temperatures for a long time. When any of these oxide layers appear, the chromium content on the metal surface will decrease, resulting in a reduced corrosion resistance in these areas. Not only should the heat tempering color and other oxide layers be eliminated, the chromium-depleted metal layer under them should also be cleaned.
5, rust spot
Thin-walled stainless steel pipes or equipment sometimes appear, indicating that the surface of the pipe is seriously contaminated. The rust must be removed before the equipment is put into use, and the thoroughly cleaned surfaces should be inspected by iron and/or water tests.
or above are factors and preventive measures for corrosion of thin-walled stainless steel pipes. The reasons for the electrochemical of the pipes are weak corrosion resistance, acidic substances and surface scratches. Therefore, in order to cope with corrosion, a material with stronger corrosion resistance should be selected; the surface should be painted with transparent silicone protective film; and the thin-walled stainless steel pipes should be avoided violent collision or friction with other objects, etc.
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