title = "Extrusion of Metals: Direct and Indirect Methods"

content = """
Extrusion is a compressive forming process in which a metal billet is forced through a shaped die to produce a continuous length of uniform cross-section. At Ridgecrest Metalworks, extrusion is primarily used for aluminum, copper, and certain steel alloys to create bars, tubes, channels, angles, and custom structural profiles.

In direct (forward) extrusion, the billet is placed in a container and a ram pushes it forward through the die. The metal flows in the same direction as the ram's movement. This is the most common method. Friction between the billet and the container wall is a significant force component and generates heat. Container liners are regularly replaced as they wear. A dummy block separates the ram face from the billet to protect the ram.

In indirect (backward) extrusion, the die is mounted on a hollow ram that moves into the stationary billet. Metal flows opposite to the ram's direction, through the hollow ram. Because there is no relative motion between the billet and the container, friction forces are much lower, allowing extrusion of harder alloys with less force and more uniform deformation. However, the process is mechanically more complex and the extruded length is limited by the ram length.

Hot extrusion is performed above the recrystallization temperature. Aluminum is typically extruded at 700–930°F (370–500°C). Steel requires temperatures of 2100–2400°F (1150–1315°C) and demands more robust tooling. Billet heating uniformity is critical; uneven temperatures cause flow defects and dimensional variation.

Extrusion defects include surface cracking (from excessive speed or temperature), internal pipe (a funnel-shaped cavity that forms at the end of the billet due to metal flow patterns), and extrusion seam (a longitudinal weld line in hollow sections made with a porthole die). The discard—the butt end of the billet that cannot be extruded—is cropped and recycled.

Die design and maintenance are critical. Dies are made from hot work tool steels such as H13. Die bearing length, entry angles, and relief geometry are engineered for each profile. Worn or damaged dies produce dimensional out-of-tolerance product and are inspected and reconditioned regularly.
"""

version = "0.0.1"
