Fittings are an essential part of any piping system, connecting pipes and allowing changes in direction, joints and connections to other pipes or fixtures. Galvanized malleable iron and malleable cast iron pipe fittings are two popular options, each with their own advantages.
Galvanized Malleable Iron Fittings
Galvanized malleable iron pipe fittings have a zinc coating that protects the base malleable iron from corrosion. They feature:
- Improved corrosion resistance – The zinc coating prevents rusting and failure due to environmental factors like acids and moisture.
- Strength and durability – The malleable iron base material is strong and ductile, resisting breakage when bent.
- Solderability – The zinc coating can be removed for joining to copper pipes via soldering.
- Wide range of sizes and types – Elbows, tees, couplings, unions and other fittings in various diameters and pressure ratings.
- Competitive pricing – Often cost less than stainless steel or non-ferrous fittings.
Malleable iron’s ductility makes it an ideal material for threaded fittings that need to be flexed, shaped or bent during installation. The zinc galvanization provides an additional layer of protection against corrosion.
Malleable Cast Iron Fittings
Malleable cast iron fittings are made from ductile iron that contains graphite nodules, giving it properties similar to malleable iron. They feature:
- Improved strength – High ductility allows for bending or flexing without damage.
- Tolerance for higher pressures – Often rated up to 300 PSI working pressure.
- Corrosion resistance – Can be galvanized or coated for use in harsh environments.
- Ability to join with multiple pipe materials – Thread, solder or weld connections.
- Low cost – Provide value for commercial plumbing and industrial applications.
The graphite nodularity of malleable cast iron creates a mix of properties, giving fittings both the strength of cast iron and the flexibility of malleable iron.
Comparing Galvanized & Malleable Iron Fittings
While galvanized fittings refer specifically to malleable iron fittings coated in zinc, malleable cast iron fittings represent a different manufacturing process that enables higher strength. Key differences:
- Working pressure – Malleable cast iron fittings can withstand higher pressures of up to 300 PSI.
- Applications – Malleable cast iron fittings are often used in commercial and industrial installations.
- Corrosion resistance – Galvanized coatings on malleable iron fittings improve corrosion resistance.