Quick Reference Guide

Metal Processing

Aluminum Alloys and Selection
An aluminum alloy is created by adding copper, magnesium, zinc, silicon and/or other elements to pure aluminum. These elements radically improve the mechanical properties, castability, strength to weight ratio and other performance characteristics of aluminum. Each alloy has been developed to provide specific properties for various applications. Chemical composition and mechanical property limits for commonly used alloys can be found in our Alloy Selection Guide (PDF). Some of the more important considerations for selecting an alloy are castability, machinability, weldability, finishing, pressure tightness, vacuum tightness, strength and corrosion resistance. Pentz assists its customers with selecting the best alloy for their application. Please contact a Pentz casting engineer for help or with any questions about the best alloy for your needs.

Heat Treating/Temper Designators
Many aluminum alloys require heat treatment to temper them sufficiently to reach the needed physical properties and required hardness. The following is a list of commonly used designators for heat treat/tempered aluminum castings followed by a comparison table of physical properties of two different alloys.

Typical Heat Treat Designators for Temper

Many aluminum alloys require heat treatment to temper them sufficiently to reach their desired physical properties and required hardness. Commonly used designators for heat treat/tempered aluminum castings include:

• (F) As-Cast - Is a casting cooled naturally at room temperature without subsequent heat treating. The temper designation for castings with no heat
  treatment is (F).
• (T5) Naturally cooled from the mold and then artificially aged to attain improved
  mechanical properties and dimensional stability.
• (T6) Solution heat treated and artificially aged to attain optimum mechanical
  properties and generally good dimensional stability.

View our table on Typical Minimum Mechanical Properties of A356 and 535 Alloys (Green Sand Molding) (PDF) with F, T5 and T6 heat treatments.

Rotary Degassing
An efficient nonpolluting process for removing hydrogen gas (degassing) from molten aluminum alloys using nitrogen as a scrubber. Hydrogen gas must be removed from the alloy to eliminate porosity in the metal and thereby improve the overall strength of the casting. Pentz utilizes state-of-the-art degassing equipment to produce the highest strength alloys available in the aluminum casting industry.

Flux Injection
Flux injection is used to accelerate rotary degassing. It removes oxides, cleans and purifies molten metal, lowers the temperature of the pour and adds density and strength to the finished casting.

Specific Gravity Testing
A standardized test method to ensure oxides and gas are removed from metal before it is poured.

Real-time X-ray
A nondestructive test (NDT) that utilizes an X-ray device in real time to detect defects such as shrink, porosity, cracks and foreign material inside castings. No expensive films or toxic chemicals are needed. Learn more about Pentz Real-time X-ray equipment.