Attention Required for Stainless Steel Plates

Effect of Surface Contamination on Stainless Steel Plates

When stainless steel plates are heated, the presence of oil on the surface can lead to variations in oxide scale thickness and composition, causing carburization. Carburized areas are prone to severe acid corrosion. Additionally, oil droplets from heavy oil burners and fingerprints from operators can significantly impact the workpiece. Hence, it’s crucial for operators to avoid direct contact with stainless steel parts and prevent contamination with new oil. Wearing clean gloves is essential. If lubricating oil is present during cold working, thorough degreasing with trichlorethylene or caustic soda solution, followed by warm water cleaning and heat treatment, is necessary. Impurities, especially organic matter or ash, on the surface will also affect oxide scale formation during heating.

Atmospheric Variations in Furnace

Differences in furnace atmosphere affect oxide scale formation, leading to unevenness post-pickling. Hence, maintaining uniform atmosphere throughout the furnace during heating is imperative. Circulation of the atmosphere should also be considered. Moisture from bricks or asbestos used in heating stands evaporates during heating, causing variations in atmosphere and oxide scale formation. Therefore, thorough drying of objects in direct contact with heated workpieces is necessary before use to prevent moisture-related discrepancies. Residual oxide scale on parts before heat treatment results in uneven oxide scale composition post-heating, affecting surface uniformity after pickling. Thus, careful attention should be paid to both intermediate heat treatment and pickling processes. Contact with gas or oil flames during heating produces varying oxide scales on the stainless steel surface. Hence, during heating, workpieces should not directly contact the flame port to ensure consistent treatment.