ANSI/ASME hatch patterns are standardized line patterns used in technical drawings to indicate different materials in section views. When a part is “cut” in a section view, hatching is applied to the exposed surface to show that solid material is present—and the type of pattern used can convey what that material is.
The most common hatch pattern is a series of evenly spaced diagonal lines, typically drawn at 45 degrees. This is the general section lining used when no specific material needs to be identified. It simply indicates that the cut surface is solid, but doesn’t specify what kind of solid.
When you want to indicate specific materials, the standard provides additional patterns. For example, cast iron might be represented with alternating thick and thin diagonal lines. Steel, bronze, brass, aluminum, concrete, and wood all have unique patterns defined by the standard. These often involve combinations of diagonal lines, dashes, or even cross-hatching. The spacing, angle, and repetition of lines are carefully controlled so the pattern can be recognized quickly, even when reduced or printed.
Using these standardized hatch patterns improves clarity and consistency across technical documents. It helps engineers, machinists, architects, and construction professionals instantly recognize both the material and the shape of internal features—especially when multiple parts or materials are shown in the same view. While CAD software usually inserts these patterns automatically, the underlying system still follows the ASME Y14.2 standard to ensure that the drawing communicates clearly across disciplines.