Buttweld ASTM A234 WP22 Class 1 / Class 3 Steel Pipe Elbow Fittings Overview of ASTM A234 WP22 Class 1 / Class 3 Buttweld Elbow Fittings ASTM A234 WP22 is a standard specification for wrought carbon steel and alloy steel pipe fittings, specifically low-alloy chrome-moly steel, designed for moderate to high-temperature and high-pressure service. The