Reasons for Leakage on the Surface of Stainless Steel Seamless Elbows
What should I do if there are leakage holes on the surface of stainless steel seamless elbows? How should we handle it again?
The occurrence of leakage holes on the surface of stainless steel seamless elbows is generally related to the following factors:
1. Material impurities and pores
Impurities such as sulfur and phosphorus in raw materials exceed the standard (>0.03%), forming micro pores that expand into leak holes under pressure;
There is incomplete gas inside the casting billet, which forms penetrating pinholes (diameter<1mm) after cold rolling. 2. Welding process defects Insufficient argon protection leads to oxidation of the weld seam, and oxygen and nitrogen are mixed into the melt pool to form pores (accounting for 70% of leakage faults); Excessive welding temperature (>150 ℃ interlayer temperature) can cause grain boundary embrittlement, resulting in microcracks due to cooling shrinkage.
3. Processing damage
During the cold forming of the elbow, excessive stretching caused stress cracks in the thinning area of the outer wall thickness;
Scratches left by surface mechanical polishing become the starting point of corrosion.
If the diameter of the leak hole is ≤ 3mm, it can be polished with an angle grinder, degreased with acetone, injected with high-temperature resistant stainless steel repair glue, scraped flat, cured for 24 hours, and then covered with metal fiber leak patch, rolled to remove bubbles and form a double seal.
If the diameter of the leakage hole is 3-10mm, a conical copper rivet should be implanted after drilling and compacted with a hydraulic rivet gun. The argon arc welding point needs to be preheated to 200 ℃ and deposited layer by layer using ER308L welding wire.
If the leakage diameter is greater than 10mm or dense, the defective section should be directly cut off, replaced with a seamless elbow that meets the GB/T12459 standard, and butt welded with argon arc welding.
Reasons for Leakage on the Surface of Stainless Steel Seamless Elbows
What should I do if there are leakage holes on the surface of stainless steel seamless elbows? How should we handle it again?
The occurrence of leakage holes on the surface of stainless steel seamless elbows is generally related to the following factors:
1. Material impurities and pores
Impurities such as sulfur and phosphorus in raw materials exceed the standard (>0.03%), forming micro pores that expand into leak holes under pressure;
There is incomplete gas inside the casting billet, which forms penetrating pinholes (diameter<1mm) after cold rolling. 2. Welding process defects Insufficient argon protection leads to oxidation of the weld seam, and oxygen and nitrogen are mixed into the melt pool to form pores (accounting for 70% of leakage faults); Excessive welding temperature (>150 ℃ interlayer temperature) can cause grain boundary embrittlement, resulting in microcracks due to cooling shrinkage.
3. Processing damage
During the cold forming of the elbow, excessive stretching caused stress cracks in the thinning area of the outer wall thickness;
Scratches left by surface mechanical polishing become the starting point of corrosion.
If the diameter of the leak hole is ≤ 3mm, it can be polished with an angle grinder, degreased with acetone, injected with high-temperature resistant stainless steel repair glue, scraped flat, cured for 24 hours, and then covered with metal fiber leak patch, rolled to remove bubbles and form a double seal.
If the diameter of the leakage hole is 3-10mm, a conical copper rivet should be implanted after drilling and compacted with a hydraulic rivet gun. The argon arc welding point needs to be preheated to 200 ℃ and deposited layer by layer using ER308L welding wire.
If the leakage diameter is greater than 10mm or dense, the defective section should be directly cut off, replaced with a seamless elbow that meets the GB/T12459 standard, and butt welded with argon arc welding.