Four welding methods of stainless steel pipe!

The welding of stainless steel pipe usually includes foundation welding, filling welding covering welding. Stainless steel pipe bottom welding is an important part of stainless steel pipe welding. It is only related to the quality of the project, but also related to the progress of the project. At present, stainless steel backing is divided into two processes: argon filling non argon filling. The back argon protection is divided into solid wire TIG process solid wire TIG water-soluble paper process; the back without argon protection is divided into flux cored wire base welding electrode based TIG welding.

Several methods of stainless steel bottom welding

TIG process is usually used for bottom welding of stainless steel. According to the actual situation of the site, we can use the following four ways to weld the bottom.

① The back side adopts blocking ventilation protection method;

② Use only soluble paper combine soluble paper with barrier plate for barrier ventilation protection;

③ Argon arc welding with flux cored wire.

④ TIG welding is carried out with covered wire.

1. A baffle is used on the back to block the ventilation protection method

When prefabricating stainless steel pipes, it is usually possible to rotate welded joints ventilate easily. At this time, the plugging plate is usually used to protect both sides of the welded joint in the pipeline for ventilation protection, while the outside is sealed with adhesive tape.

During welding, the process of early ventilation delayed exhaust should be adopted. The outer edge of the adhesive tape is torn off. Since the baffle is composed of rubber white iron, it is easy to be damaged, so this welding method can ensure the inner side of the weld. It is full of argon its purity, so as to effectively ensure that the metal inside the weld is oxidized the welding quality at the bottom of the weld is ensured.

2. Use only soluble paper a combination of soluble paper baffles for blocking ventilation protection

When installing welding the fixed end of stainless steel pipe, the internal ventilation is more difficult some sides are easier to be blocked. In this case, a water-soluble paper baffle can be used for blocking. That is, the side with high permeability easy to remove is blocked by baffle, the side with high permeability difficult to remove is blocked by water-soluble paper, the outside is sealed. Weld the joint with tape.

When welding stainless steel fixing mouth, in many cases, there is no ventilation on both sides of the weld. At this time, how to ensure that the weld is filled with argon protection becomes a problem. In the actual construction on site, we use water-soluble materials on both sides of the weld. Blocking paper, exhausting gas the center of welding seam sticking with adhesive cloth on the outside successfully solved the above problems.

When water-soluble paper is used to block the ventilation, since the ventilation is conducted the center of the weld, the vent pipe should be pulled out quickly at the sealed joint, the residual argon inside should be used for protection. The bottom is quickly completed the mouth is sealed.

In this method, it should be noted that the water-soluble paper should be double-layer pasted well. Otherwise, the water-soluble paper will be damaged dropped, the inner weld will lose the protection of argon, which will lead to oxidation, which will cause the weld to be cut again. Welding can only ensure the welding quality, but also seriously affect the construction period. Please paste water-soluble paper before strict inspection.

In many construction sites, we have used this welding method for primer, which can effectively ensure its quality, there are difficulties in construction. Therefore, we should choose a serious skilled welder.

3. The back is protected by argon, flux cored wire TIG process is adopted

This method has been used in China for several years, now e308t1-1, e308lt1-1, e309t1-1, e309lt1-1, 347t1-1, e316t1-1, e316lt1-1 other flux cored wires have been produced applied in this field, good economic benefits have been achieved.

Because the back side is filled with argon, its advantages are obvious, such as high efficiency, simple, low cost, suitable for installation in construction site. However, due to its structural characteristics, flux cored wire has higher requirements for welders in the process of operation, with fast wire feeding speed high wire feeding accuracy. It's hard to master. Before welding, the welder should be trained skilled. In the construction sites of Yanba in Nanjing abroad, we have successfully solved the problem that argon cannot flow between the contact port the maintenance port.

4. The back side is protected by argon flow, flux cored wire TIG process is used.

In the 1990s, Japanese steel other companies developed primer lines. In recent years, China has also developed a stainless steel primer line, which has been used in practical construction achieved good results. This method has been successfully applied to the capacity expansion reconstruction project of Wuxi petrochemical company.

The protection mechanism of TIG process for stainless steel bottom wire is: the rear weld is protected by metallurgical reaction of slag produced by welding wire its alloy elements, the front weld is protected by argon, slag slag. Alloy elements.