Tuesday, June 30, 2015

You Get What You Pay For: 5 Reasons Trusts Trumps Price When Purchasing Bronze

Bronze has been both utilized for and in a variety of products throughout history, including tools, weapons and armor. As well, it has been used to cast beautiful sculptures since craftsmen first discovered the practice in ancient Greece. Today, Bronze is ideally used for bearings, bushings, wear plates, heavy duty guides and springs.

Unfortunately, the price of bronze has risen dramatically over the past decade, causing manufacturers, architects and sculptors to seek more economic alternatives. This is due to the fact that copper, a main component of bronze, has become increasingly expensive.

In 2000, copper cost just under $1 a pound. However, as the Great Recession hit in 2007, the price soared to $5 per pound. Even though the price has since simmered down, the metal’s price still hovers around $3 per pound. This 200% increase over the last decade has caused a dramatic effect on the modern use of bronze.

Sculptors, who once used bronze as the main component in their art, have converted to using cheaper alternatives like Aqua-Resin, concrete, Fiberglass, gypsum- and polyurethane-based resins, plaster and terra cotta.

Commercially, the cheaper alternative to using bronze is brass, due to its composition of copper and zinc. However and most importantly, some copper-based alloy such as Aluminum Bronzes offer a combination of mechanical & chemical properties unmatched by any other alloy series.  This feature often makes copper-based alloys the first choice for demanding applications. 

Additionally, industry professionals know that you must trust the metal you are working with. Thus, I’ve come up with five reasons to consider purchasing bronze despite its cost.

  1. It contains excellent corrosion resistance – especially in seawater and similar environments, where the alloys often outperform many stainless steels
  2. Exhibits good weldability – making fabrication economical
  3. Good resistance to fatigue- ensuring a long service life thus saving time & money down the road
  4. Some aluminum bronzes exhibit strengths comparable to low alloy steels and many are stronger than most stainless steels. For instance in Bridge Applications – some bronzes thrive on heavy loads, shocks and harsh working environments thus making it a perfect fit for bridge bearings. When lubrication of sliding surfaces is less than ideal, aluminum bronzes are superior to ferrous materials.
  5. Non-Sparking Characteristics – Excellent non-sparking characteristics make aluminum bronzes suitable for manufacture of tools and equipment used in the handling of explosives, in mines, petroleum and chemical plants, gas-handling equipment and similar applications.

Tuesday, June 23, 2015

A Sacrificial Metal: Why Bronze is So Selfless

Consider the following definition of sacrifice from the American Heritage Dictionary: “to sell or give away at a loss.” In accordance with this definition, bronze can be considered a sacrificial metal, in which it offers itself up to serve a piece of equipment that would otherwise be unable to withstand climatic or severe operating conditions.

Last year, I posted a blog titled, “
The Bronze Fish,” detailing how aluminum bronzes are naturally suitable for water applications due to their great resistance to water corrosion. When metallurgically bonded to metals such as steel, which is not ideally suitable for water, aluminum bronzes add strength and durability to the part.

Aluminum bronzes are most commonly used in water applications because of their great resistance to corrosion in a variety of water environments. However, bronze does not only work well in various water environments, but it can also be used in rural and industrial atmospheres.

As a sacrificial material, bronze can be utilized anywhere metal is rubbing on metal. Upon being placed between two pieces of metal, usually steel, the bronze acts as a buffer. When the pieces of steel rub together or move, the bronze bearing absorbs the friction. By doing so, bronze accepts the loss of its own metal as time goes on in order for the steel, or the other metal, to continue fulfilling its operational purpose.

The following attributes are just some of the traits that make bronze a successful bearing material:
  • Low coefficient of friction versus hard shaft materials
  • Corrosion resistance
  • Easy and economic manufacturability
  • Cost effectiveness and availability
  • Ability to absorb friction
  • Ductility

But what makes bronze so selfless?

Although there are various compositions for bronze, being an alloy of copper and tin allows the material to withstand many corrosive factors that other metals cannot endure, such as climatic conditions; weather and exposure to rain, wind and sun; pollutants in the atmosphere; heavy loads and increased speeds; and patination.

Overall, bronze takes a licking and keeps on ticking!