What Are The Common Welding Defects Of Stainless Steel Pipe Fittings

Common types of stainless steel pipe fittings include:Stainless Steel Weld Tee, stainless steel elbows, stainless steel reducers, stainless steel pipe caps, etc. In order to avoid the leakage of the potential leakage point between the valve body and the flange due to the pressure, an annular cavity is set at the joint of the fixture and the outer edge of the valve body flange for injection. Because the fixture of the different diameter flange is easy to shift to the small diameter flange side during the injection process, the limit measure of tooth contact clamping is selected. After the sealant is cured during operation, the effect is checked, and partial refilling and compaction are carried out to avoid stress relaxation, and then the injection hole is closed.

When producing stainless steel pipe fittings, welding will be carried out during use. There are the following five defects in the appearance of the weld, which can be found by naked eyes and repaired in time. If the operation is proficient, it can generally be avoided.

1. Weld bite edge: The bite edge formed along the edge of the weld on the welded elbow is called bite edge. It not only reduces the working section of the joint, but also causes serious stress concentration at the bite edge.

2. The weld is too high: This phenomenon occurs when the welding groove angle is too small or the welding current is too small. Since stress concentration is prone to damage, in order to improve the fatigue life of the pressure vessel, it is necessary to flatten the weld.

3. Burn-through: Burn-through refers to the leakage of some molten metal from the other side of the weld, or even burning into holes, thereby reducing the strength of the joint.

4. Weld concave: Due to the reduction of the working section of the weld, the strength of the joint is reduced.

5. Welding: The molten metal flows to the undissolved weld elbow at the edge of the molten pool, accumulates to form a sintering, and does not weld with the weld elbow. Welding nodules have no effect on static load strength, but will cause stress concentration and reduce dynamic load strength.

During the use of stainless steel stamping elbows, leakage may occur due to improper connection of stainless steel stamping elbows or long years of use. Users do not need to panic in this situation. Mainly check the leaking parts. In the leaking parts, it is generally impossible to inject sealants through the gaps due to the gaps in the connection of stainless steel stamping elbows to remove the leakage. The sealing construction method is based on the on-site survey of the leakage site. In order to achieve limited plugging, the fixed clamp method is used to accommodate the leakage point to form a sealing cavity, and the sealant is injected to eliminate the leakage. The clamps on one side are all custom-made. The clamp list is mainly to accommodate the leakage point, and the main key is to establish a sealing cavity between the valve body flange and the pipeline flange connecting the short flange.

Stainless steel elbows are not afraid of weak corrosive media such as air, steam, and water, and chemically corrosive media such as acids, alkalis, and salts. It is also called stainless steel that is not afraid of acid. In actual use, steel that is not afraid of weak corrosive media is often called stainless steel stamping elbows, and steel that is not afraid of chemical media is called acid-resistant steel. Due to the difference in chemical composition between the two, the former is not necessarily not afraid of chemical media corrosion, while the latter is generally stainless. Chromium-containing stainless steel elbows also combine mechanical strength and high elongation, are easy to process and manufacture components, and can meet the needs of architects and structural designers. All metals react with oxygen in the atmosphere to form an oxide film on the surface.