Alloy Steel AISI 5150

General Characteristics Alloy Steel AISI 5150

Alloy 5150 is a medium-carbon, chromium steel with good strength, toughness and hardenability

Chemical Analysis

C% Mn% P% S% Si% Cr%
0.48/0.53 0.70/0.90 0.040 max 0.040 max 0.20/0.35 0.70/0.90


This alloy is used in the production of forged components that are subjected to normal stresses for automotive and general engineering.


This alloy would be forged between 2150 and 1600ºF ( 1175 and 870ºC.) The alloy should be slow cooled after forging or transferred to a furnace around the ‘finishing’ temperature.

Heat Treatment

Annealing: The microstructure for this alloy to give optimum machinability is one of course lamellar pearlite to coarse spheroidite. This might be obtained by austenitizing at 1380ºF (750ºC) followed by an iso anneal at 1250ºF (680ºC.)

Normalizing: A nominal normalizing temperature for this alloy is 1600ºF (870ºC.) This treatment is followed by air cooling
Hardening: Austenitize at 1475-1550ºF (800-845) and oil quench for small, intricate sections and water quench for large, simple sections.

Tempering : from 1000-1250ºF(540-680ºC) as per required properties.

Machinability: This alloy is readily machined from a coarse pearlite to a coarse spheroidite microstructure.