Bronze and brass are two of the most common materials used to produce valves. This preference comes because both metals are quite malleable. They both are artificially made from natural metallurgical elements: brass is made from copper and zinc, while another is made primarily from copper and tin. Each metal offers valves numerous and various advantages, though which one is preferable for your application may be worth discussing.

Bronze Valves

The Romans were probably the first to manufacture flow control valves--very similar to those of today--out of bronze as early as the 1st Century B.C.

One drawback of bronze is that bronze globe valves can only be produced by casting or by machining cast ingots. The rough exterior of bronze--which is known for porosity and shrinkage cavities--is a direct result of casting. But on the upside, bronze is fairly inexpensive, more than ductile, and is of great for resisting corrosion, particularly from any corrosives similar to seawater.

Brass Valves

More malleable than bronze, brass is also more versatile, as different combinations of copper and zinc create a wide range of brasses with varying properties.

Brass also lends itself very well to manufacturing, as it can be cast, forged, heat extruded, or cold drawn in its creation. It is very machinable, and its smooth surface helps keep costs down.

Brass is highly corrosion resistant. Unfortunately, high levels of chlorine can break down zinc content. Otherwise, brass is perfect for a variety of media, including natural gas. And, for potable water, brass is a natural choice over bronze, as it typically contains much lower levels of lead than bronze.

Of course, by today's standards, these contrasts and comparisons are rudimentary. Today's foundries cast superior bronze alloys which are utilized for countless applications, though use for potable water is slowly being phased out. Brass (because of the zinc content)--are being produced via hi-tech fabricating techniques using chemicals and heat. These breakthroughs in metallurgy help to negate a need for lead in the mix, and increase the longevity of piping and  valves, ensuring the continued use of brass for years to come. But, while brass enjoys several advantages over bronze, don't count it out just yet. Lead Free Bronze valves (bronze valves meeting or exceeding Clean Water Act lead restrictions) are readily available, and are generally the first choice for water pipes with diameters under 3" when keeping costs down is a must.