In petrochemical installations, there are often a large number of stainless steel pipes (including furnace tubes) that require on-site welding. With the rapid development of petrochemical industry, more and more large-scale petrochemical plants use large-size pipelines, putting forward higher requirements for on-site installation and construction. In order to ensure the quality of the pipeline welding and pipeline cleanliness, usually using argon arc welding primer. TIG welding of stainless steel, stainless steel and oxygen because of the great affinity, if you do not take weld protection measures, the back of the weld metal is easily oxidized in the welding process, alloying elements burn, and easy to produce welding defects, resulting in Weld metal mechanical properties and corrosion resistance decreased. In the stainless steel pipe welding, in order to ensure the welding quality of the back of the weld, we must take effective protective measures. This article describes several effective ways to protect the back of the weld during stainless steel argon arc welding. First, the tube filled with argon to protect the petrochemical plant Stainless steel pipe TIG, the general method of argon tube to prevent the back of the weld oxidation. Argon method includes the overall argon and local argon filling and so on. In order to save the construction cost and meet the construction requirements, the construction process should be based on the specific construction conditions of the pipeline and make flexible use of the method of filling argon inside. 1. The overall argon law For small diameter pipe or tube group on the pipeline is shorter, the overall argon can be used, the method is relatively simple. Argon method as a whole: both ends of the tape (cardboard, rubber plates, etc.) sealed by the tube filled with argon at one end, the other end of the upper seal on a 3 ~ 5mm discharge hole, mainly to prevent the arc Argon gas pressure is too large, resulting in joint arc difficult, resulting in pit and other defects. In addition, in order to prevent a large amount of argon at the mouth of the gap emissions, previously available tape to seal a section of the nozzle, leaving only a welder for a continuous welding length. After welding this section, tear the same length of tape, and then welding, and so on, until the welding is completed. The overall argon as shown in Figure 1. Figure 1, the overall nitrogen filling 1 nitrogen filled hose; 2 nitrogen; 3 tape 2. Local Argon Method When the pipe diameter is larger, longer pipe, if directly to the tube argon, welding quality is not easy to guarantee and will be wasted A lot of argon, increasing engineering costs. To save argon, argon can be used locally. Local argon can be water-soluble paper method. Before the group, water-soluble paper was affixed 150mm away from both sides of the weld in the tube to form a group of temporary blocking plates. Argon gas was filled into the tube at the gap of the opposite port (see Figure 2). When the piping system is hydrostatically tested, the water-soluble paper dissolves quickly in the water and is removed with water without adversely affecting it. In addition, argon charging fixture can be made for local argon protection, argon charging fixture shown in Figure 3. Argon clamp before welding will be placed in advance on both sides of the tube, the fixture will be removed from the tube after welding. This method is suitable for stainless steel pipe ground prefabricated, simple and easy.