The quality problems of seamless stainless steel elbows are mainly concentrated in three categories: processing defects, material deviations, and dimensional errors, which directly affect the sealing, pressure resistance, and service life of pipeline connections.
The common quality issues and their impacts are as follows:
Uneven wall thickness: Uneven force during bending processing results in the inner wall of the elbow being too thin and the outer wall being too thick. The pressure resistance of thin areas decreases, making them prone to rupture under high pressure conditions.
Crack defect: If the heating temperature is too high or the material contains impurities, small cracks may appear on the surface or inside after bending. Cracks will expand during use, causing medium leakage.
Angle deviation: The machining positioning is inaccurate, and the actual angle of the elbow (such as 90 °, 45 °) deviates from the design value by more than ± 1 °. It is difficult to connect during on-site installation and requires additional adjustments, which affects the overall sealing of the pipeline.
Material non-compliance: Using inferior stainless steel (such as low nickel chromium material) to impersonate qualified materials significantly reduces corrosion resistance, making it prone to rusting in humid or corrosive environments and shortening its service life.
Appearance defects: There are dents, scratches, burrs, or oxide scales on the surface that have not been cleaned. Dents are prone to accumulation of dirt, burrs can increase fluid resistance, and may also scratch the sealing gasket, leading to seal failure.
Focusing on checking the above issues during daily selection or acceptance can effectively avoid risks.