The internal surface quality of stainless steel fittings such as 90° elbow, clamp bend, and welded bend directly affects hygiene and corrosion resistance.
This is especially critical in food and pharmaceutical piping systems.
Surface Roughness (Ra) Requirement
For hygienic applications, typical Ra values include:
Ra ≤ 0.8 μm – standard use
Ra ≤ 0.6 μm – improved cleanability
Ra ≤ 0.4 μm – high purity systems
A smoother surface inside a sanitary elbow or pipe bend reduces residue buildup and improves CIP efficiency.
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Surface Finishing Process
Different fittings like butt weld elbow, tri clamp bend, and long radius bend are processed by:
Mechanical polishing
Electropolishing (EP)
Bright annealing (BA)These treatments ensure consistent surface quality across all stainless steel bends.
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Material Testing for Stainless Steel 90° Elbow and Bend
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Inspection Method
Each 90 degree elbow or clamp type bend is tested using a roughness tester:
Measure internal surface
Multi-point verification
Record Ra valueAll products comply with European standards such as EN 10357 and DIN 11850.