It is important for you to know the major risks that can occur when you embark on a stainless steel tube repair project. This ensures that you can take necessary precautions to forestall such risks. Below are some of the risks that hobbyists should guard against when performing stainless tube repairs.
You should do everything possible to keep hydrogen away during the welding process. For example, make sure that your stainless steel tube isn't moist. Weld rods shouldn't be damp. The water vapour formed when this moisture is heated can release hydrogen that can cause your tube to be porous after the weld joint has cooled.
The presence of high levels of oxygen during the welding process can have adverse effects. First, the oxygen will react with the molten stainless steel and form a chromium oxide layer on the surface of the area being welded. This heavy slag (chromium oxide) may keep extinguishing the arc in case you are using arc welding equipment. Secondly, the formation of excessive amounts of the oxide drains chromium from the surrounding sections of the tube. As you remove this slag, you may reduce the corrosion resistance of your tube in case substantial amounts of chromium keep being lost in that slag. It is therefore prudent for you to use a shielding gas so that you limit the extent to which oxygen reacts with the hot metal during the welding process.
You should also ensure that the welding rods that you use do not contain cellulose. Cellulose contains high amounts of carbon that can react with the chromium in stainless steel. Corrosion resistance can, therefore, be compromised. Similarly, the tube should be free from grease and oil to keep carbon away from the weld area.
Lead or Copper Contamination
The existence of lead or copper particles on the surface of the stainless steel tube that you intend to weld can make the tube to become brittle or crack after you have finished welding. This is because those contaminants will disrupt the uniformity of the microstructure of the stainless steel. Special care must, therefore, be taken to clean the surface thoroughly so that no contaminant remains to affect the outcome of the repair project.
Many of the problems above can be avoided if you take some time to research and understand the unique attributes of stainless steel. Alternatively, ask an expert to guide you so that your DIY repair project produces the desired outcomes.