Bronze VS Cast Iron Globe Valve: Appearance Revealed

The differences between Bronze Globe Valve and cast iron globe valve in appearance are mainly reflected in color, surface texture and weight density.

Bronze globe valves usually have a yellow-green or bright metallic luster and are generally not painted to preserve the original color of their material. High-end products are sometimes polished to enhance the luster. In contrast, the surface of cast iron globe valves is mostly black, silver-gray or other dark tones, and some products are painted with black or silver anti-rust paint. After long-term use, cast iron valves may develop oxidation rust spots, causing the color to darken.

In terms of surface texture, bronze globe valves are relatively smooth and flat, with fine casting technology, and usually no obvious pores or sand holes. When touched, bronze valves give people a sense of metal coolness, but the touch is more delicate. The surface of cast iron globe valves appears rough, with common casting defects such as air holes, sand holes, black spots or white spots, and the edges may have burrs. In terms of feel, cast iron valves are rough, especially at the casting joints, which may be uneven.

In terms of weight and density, bronze stop valves are significantly heavier than cast iron valves of the same size due to their higher density (about 8.8 g/cm³). When a bronze valve is knocked, a crisp metallic sound is emitted.

There are significant differences between bronze stop valves and cast iron stop valves in terms of physical properties, connection methods and surface treatment.

In terms of density and weight, bronze material is relatively light, with a density of about 7.2 g/cm³, and the sound is dull when knocked. In terms of connection ends and structural features, bronze stop valves are usually threaded (applicable to specifications below DN50), and the flange edge is thinner when flanged, with high machining accuracy. Its valve body and valve cover are mostly connected by flange or thread, and the valve stem is generally designed as a lifting and rotating rod (open stem structure). In contrast, cast iron stop valves are mostly flanged (applicable to specifications above DN50), with thicker flange edges and unfinished surfaces. The valve body and valve cover of cast iron stop valves are mainly connected by bolts or integral casting, and the valve stem is mostly a concealed stem structure.

In terms of casting identification and painting, bronze stop valves are usually not additionally painted, and some products have "bronze" or "CuSn" material identification marked on the nameplate. The surface of the cast iron stop valve may be coated with black anti-rust paint, and the nameplate is marked with "cast iron" or "Cast Iron". It is worth noting that some low-pressure valves will retain the original unpainted cast iron color on the sealing surface.