ASTM A403 WP304 Stainless Steel 90° Elbow Fitting B16.9

ASTM A403 WP304 stainless steel fittings are among the most widely used austenitic stainless steel fittings. The ASTM A403 standard specifies strict requirements for chemical composition, mechanical properties, heat treatment, dimensional tolerances, non-destructive testing, and marking for wrought butt-weld, socket-weld, and threaded fittings manufactured from UNS S30400.

The primary difference between WP304 and WP304L materials is the carbon content. WP304 has a standard carbon content with an upper limit of 0.08%, while WP304L is an ultra-low carbon version with a strict limit of 0.030% carbon content.

This difference affects intergranular corrosion resistance and weldability. When exposed to temperatures between 425°C-850°C, carbon combines with chromium to form chromium carbides, reducing chromium content near grain boundaries and creating corrosion-prone areas. WP304 requires post-weld solution treatment to restore microstructure, while WP304L maintains excellent corrosion resistance without heat treatment, saving time and costs.

• Chemical and petrochemical industries
• Food and beverage processing
• Pharmaceutical industry
• Water treatment and distribution
• Building water supply and drainage
• HVAC
• Marine industry
• General industry