Industry
Fact-checked

At AboutMechanics, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What are Malleable Fittings?

Malleable fittings are versatile connectors in plumbing and gas systems, crafted from malleable iron that can withstand high pressures and temperatures. Their durability and flexibility make them ideal for creating secure, leak-proof seals in diverse applications. Intrigued by how these fittings can enhance your project's integrity? Discover their full potential in our comprehensive guide.
Larry Ray Palmer
Larry Ray Palmer

Malleable fittings are a type of pipe fitting generally made of iron. These items are commonly used for electrical conduit and various plumbing connections. The malleable fitting gets its name from the type of iron from which it is cast — white iron. Upon casting, it is a very brittle metal. Through the process of annealing, the white iron is softened into one of the three forms of malleable iron.

Blackheart malleable iron is used in production of malleable plumbing fittings. The blackheart iron gives the malleable fitting its dark color, and these connectors are commonly known as black pipe fittings. In some cases, a malleable fitting is galvanized to protect the pipe fitting from corrosion. Galvanization is a process in which a zinc coating is applied to the fitting. The malleable pipe fitting is usually threaded to make assembly of pipes and fittings easier. Basic joints can be made using hand tools and malleable fittings while more crucial joints may employ thread sealants.

Malleable fittings fell out of favor when cheaper materials like copper gained popularity.
Malleable fittings fell out of favor when cheaper materials like copper gained popularity.

The plumbing industry used malleable fittings and pipes for many years until copper, PVC, and PEX pipe became more economical. Due to concerns about chemicals such as zinc leaching into drinking water, galvanized malleable fittings are no longer commonly found in home plumbing systems. While the malleable fitting is still in use for high pressure applications, modern construction tends to use the less expensive and safer pipe fitting options for other applications.

Modern malleable fitting usage is primarily restricted to the plumbing of gas lines.
Modern malleable fitting usage is primarily restricted to the plumbing of gas lines.

Modern malleable fitting usage is primarily restricted to the plumbing of gas lines and high pressure steam used for heating and industrial application. Threaded fittings and pipes make malleable fittings suitable for creating tight connections using hand tools and thread sealants. These airtight joints with the ability to withstand high internal pressures are necessary for the safe delivery of gases or steam. The use of malleable iron pipe and fittings for the transmission of steam first became popular in the United States during the 1840s. The malleable fitting was primarily used in the construction of steam radiator heating systems at that time.

Galvanized malleable fittings are commonly used in outdoor electrical conduit applications. The zinc coating of the galvanized malleable fitting provides resistance to corrosion which could compromise the conduit and leave electrical wiring exposed. The natural strength and rigidity of the galvanized iron pipe and fittings serve to protect the electrical wiring from physical damage caused by crushing or abrasion.

You might also Like

Discuss this Article

Post your comments
Login:
Forgot password?
Register:
    • Malleable fittings fell out of favor when cheaper materials like copper gained popularity.
      By: Sergejs Katkovskis
      Malleable fittings fell out of favor when cheaper materials like copper gained popularity.
    • Modern malleable fitting usage is primarily restricted to the plumbing of gas lines.
      By: evp82
      Modern malleable fitting usage is primarily restricted to the plumbing of gas lines.