Porosity Guide: Gas & Shrinkage Voids in Castings & Welds

Porosity Guide: Gas & Shrinkage Voids in Castings & Welds

Short answer: Porosity is the network of gas and shrinkage voids trapped inside castings and welds; it weakens the section, leaks under pressure and ruins pressure-tight parts, so it is prevented by melting, gating and welding discipline and found via NDT.

At a Glance

Porosity Guide: Gas & Shrinkage Voids in Castings & Welds chart
Figure 1 – Porosity Guide: Gas & Shrinkage Voids in Castings & Welds overview.

Types of Porosity

Gas porosity comes from dissolved hydrogen/moisture; shrinkage porosity from poor feeding. Both appear in Weld Defects Guide e Aluminum Casting Defects Guide, and reduce Yield Strength Vs Tensile Strength and pressure integrity.

Preventing Porosity

Dry flux and degas melts (Casting Supplier), design risers/chills, keep welds clean and dry (Como soldar alumínio, Metal Degreasing Guide), and control solidification. Relate to Metal Formability Guide only indirectly.

Detection & Supply

Find porosity by radiography/UT via Metal Ndt Guide, quantify per Mill Test Certificate Guide, and read failures in Metal Failure Analysis Guide. HXSCO supplies low-porosity cast and welded parts with NDT records.

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Perguntas frequentes

What is porosity in metal?

Gas or shrinkage voids trapped inside a casting or weld, weakening the section and causing leaks.

What causes porosity in welds?

Moisture, dirty base metal, damp shielding gas and poor technique entrain gas.

How do you prevent casting porosity?

Dry flux, degas the melt, good gating/risers and controlled solidification.

How is porosity detected?

Radiography, ultrasonic testing and pressure testing — part of NDT.

Do you supply low-porosity parts?

HXSCO supplies cast and welded parts with NDT porosity records on request.

Source Sound Metal from HXSCO

HXSCO supplies low-porosity cast and welded components with NDT porosity records. Send your specification and quantity for a quote.

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