GMW16436

Description / Abstract: Introduction

Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose. This standard covers the process for determining and reporting the microstructural fineness of aluminum castings. Two (2) methods are presented in this standard:

Method A (Appendix A). Secondary Dendrite Arm Spacing (SDAS) as measured via the linear intercept method.

Method B (Appendix B). Mean Linear Dendrite Spacing (MLDS) as measured via an image analysis routine.

Applicability. This standard applies only to aluminum castings which have well defined dendrite arms evident in the microstructure. It is not suitable for characterization of near eutectic, eutectic or hypereutectic aluminum alloys.

Remarks. These methods provide a quantitative representation of the two dimensional (2-D) microstructure of hypoeutectic aluminum castings. It is important to note that these two (2) methods will not produce identical results.