An Introduction to Galvanized Malleable Iron Pipe Fittings

by | Aug 3, 2023 | News

Malleable iron pipe fittings are a staple component for various residential, commercial and industrial plumbing applications. Galvanizing adds an extra layer of protection to these already rugged fittings. Let’s examine what makes galvanized malleable iron such a popular piping solution for contractors and end users.

China pipe fittings elbow malleable cast iron

What Is Malleable Iron?

Malleable iron starts as a cast iron material that is then heat-treated to increase its ductility. This process realigns the molecular structure of the iron, making it more flexible and less brittle. Malleable fittings can thus handle threading, pressure changes, vibration and thermal expansion without cracking or fracturing. The material retains the strength of cast iron, however, making it well-suited for demanding pressure applications. Malleable iron pipe fittings have a pressure rating of up to 300 PSI for threaded connections.

Benefits of Malleable Iron Fittings

Malleable iron pipe fittings offer numerous advantages, including:

  • High strength and durability for long service life
  • Ability to withstand high pressures without leaking or rupturing
  • Withstands vibration and thermal expansion stresses
  • Can be threaded for standardized pipe connections
  • Available in a wide variety of shapes and sizes
  • Relatively low material cost compared to steel or copper

This combination of performance and affordability makes malleable iron a go-to choice for water, gas, steam and other piping systems.

What Is Galvanizing?

Galvanizing refers to applying a protective zinc coating to steel or iron materials. It is achieved by submerging the iron component in a bath of molten zinc. The zinc alloyes with the iron to form durable layers of zinc-iron alloy crystals on the external surface. This galvanized coating prevents water and oxygen from reaching the underlying iron.

Benefits of Galvanized Coatings

There are several key benefits provided by galvanized coatings:

  • Excellent corrosion resistance. The zinc coating sacrificially corrodes before the base iron to provide cathodic protection. Galvanised malleable iron pipe fittings greatly expand the service life in wet environments or when exposed to corrosive substances.
  • Impact resistance. Zinc coatings can withstand considerable impact without cracking or flaking off.
  • Negates need for painting. The dull gray zinc finish doesn’t require any additional painting.
  • Allows for downstream welding. Galvanized materials can still be welded, unlike painted finishes. The zinc vaporizes near the weld zone to accommodate strong welds.
  • For these reasons, galvanizing is an ideal way to protect iron pipe fittings used in demanding industrial or outdoor applications.

Galvanized Malleable Iron Fittings Offer The Best Of Both Worlds

Galvanized malleable iron pipe fittings combine the inherent strengths of malleable iron with the lasting corrosion resistance of a thick zinc coating. This yields fittings that are:

  • Strong and durable enough for high pressure applications
  • Able to withstand years of use and abuse without failure
  • Threaded on ends to enable standardized pipe connections
  • Protected against rust and corrosion in wet/humid environments
  • Able to endure exposure to chemicals, acids, road salt and other contaminants
  • More economical than solid stainless steel fittings
  • Visually appealing with a clean finished look

Galvanized fittings are available in the full range of styles, shapes and sizes – from nipples and elbows to tees, couplings and flanges. This allows complete piping systems to be assembled using only galvanized malleable iron components. The end result is an affordable yet extremely durable piping infrastructure.

Typical Applications For Galvanized Fittings

Here are some of the many applications where galvanized malleable iron fittings thrive:

  • Wet fire suppression sprinkler systems
  • Gas service lines
  • Potable water plumbing
  • Drainage and vent lines
  • Swimming pool piping systems
  • Landscape irrigation systems
  • Chemical processing plants
  • Pulp/paper mill equipment
  • Water treatment facilities
  • Pressure vessels and tanks
  • Steam boiler components
  • Roadway lighting, traffic signals, signs

With capabilities that span residential to ultra-heavy industrial settings, galvanized iron is truly an exceedingly versatile material. Any project that demands iron-strength, zinc-toughness and long service life can benefit from the use of galvanized malleable iron fittings.

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