What are the process flow and steps of stainless steel composite pipe welding?

Stainless steel composite pipe is often used in guardrails and railings. It is relatively good in terms of wear resistance and corrosion resistance. For stainless steel composite pipe, its requirements are relatively strict, and it must be hard and shiny. Stainless steel composite pipe in the production of the steps is more rigorous, which is an important step is welding. The temperature, humidity, welding rod and temperature required for welding are different. Production should be carried out according to the purpose to make its performance and characteristics reach the standard. The technical performance required for welding of stainless steel composite pipe is relatively high, and many masters do not have the ability to weld. The following is a small series to introduce the relevant welding steps for your reference:

1. There are two kinds of stainless steel composite pipe welding rod: titanium calcium type and low hydrogen type. DC power supply can be used as much as possible for welding current, which is beneficial to restrain the redness and penetration of welding rod. The electrode of titanium calcium type drug skin is not suitable for full-position welding, only suitable for flat welding and flat fillet welding. The electrode of low hydrogen type drug skin can be welded in full position.

2, stainless steel composite pipe welding rod in the use of should adhere to the boring. In order to avoid cracks, pits, pores and other defects, the titanium calcium type coating is dried at 150-250 ℃ for 1h before welding, and the low hydrogen type coating is dried at 200-300 ℃ for 1h before welding. Can not be repeatedly dried, otherwise the medicine skin is easy to fall.

3, weld clearance clean, but also to avoid the welding rod stained with oil and other dirt, so as not to add the weld carbon content and affect the welding quality.

4, in order to avoid heating and intergranular erosion, welding current should not be too large, ordinary should be about 20% lower than carbon steel electrode, arc should not be too long, fast cooling between layers, narrow channel welding is appropriate.

5, should try to use short arc welding, arc length of ordinary 2-3mm, the arc is too long prone to thermal cracking.

6, transport: short arc welding should be used, the general does not allow the lateral swing, the goal is to reduce the stainless steel composite pipe welding heat and heat affected zone width, progress weld intergranular erosion resistance and reduce the tendency of thermal cracking.

7, stainless steel composite pipe welding strategy should be stable selection of welding rod, to avoid improper selection of welding rod show hot crack or high temperature heat treatment caused by sigma phase precipitation, so that the metal embrittlement. Refer to the stainless steel composite pipe and dissimilar steel electrode selection specification for selection, and accept the appropriate welding process.

The welding process and manufacturing process of stainless steel composite pipes are relatively rigorous, and the performance requirements for the technology are relatively high. Welding should be carried out in accordance with relevant steps. If problems occur, accidents will occur, especially for bridge guardrails, railings and facilities used in traffic made of stainless steel composite pipes. Therefore, accidents must be qualified for welding!