Through hardening is used when the objective is to harden the full cross-section of a component rather than only the surface. The part is heated to the austenitizing range and quenched so martensite forms through most or all of the section, followed by tempering to obtain the required hardness-toughness balance.
This approach is appropriate when the whole component must carry high strength rather than relying on a hard case over a tough core.
Achievable through-hardness depends on steel hardenability, part size, section thickness, and quench severity.
At Braddock, through hardening would be specified for components that need bulk hardness and strength throughout the load-bearing section.
Through hardening is common on steel parts where full-section strength and hardness are required.
The part is heated to the austenitizing temperature appropriate to the alloy and then quenched in oil, polymer, water, gas, or another selected medium. Tempering follows to reduce brittleness and develop the specified final hardness.
Uniform through-hardening requires a material with adequate hardenability relative to section size.
Large sections in low-hardenability steels may harden only near the surface, even if the intent is full-section hardening. Quench cracking, distortion, and decarburization must also be considered.
Braddock would control austenitizing temperature, hold time, quench medium, agitation, and tempering cycle to produce the specified core hardness and microstructure.
