Hardness and Heat Treatment Potential of AISI 1045

AISI 1045 is a medium carbon steel known for its excellent balance of strength, toughness, and machinability. But one of its most valuable features is its versatile heat treatment potential, especially when hardness is a key requirement.

In its as-rolled or normalized condition, AISI 1045 typically has a Brinell Hardness (HBW) of around 170–210, which is suitable for general-purpose applications such as shafts, bolts, and machine parts. However, when increased surface hardness or wear resistance is needed, heat treatment becomes essential.

Through hardening (quenching followed by tempering) allows AISI 1045 to reach Rockwell C hardness values of 50–55 HRC, depending on the quenching medium and tempering temperature. This makes it an excellent candidate for high-stress, high-wear components like gears, pins, and axles.

Additionally, induction hardening can be applied to selectively harden surface areas while retaining a tough core—ideal for parts that require both durability and impact resistance.

What sets 1045 apart from alloy steels is that it delivers high hardness without costly alloying elements, making it a cost-effective solution for many medium-duty industrial needs.

In summary:

Base hardness: \~170–210 HBW
After heat treatment: Up to 55 HRC
Suitable for wear parts, tools, and heavy-duty machinery components

AISI 1045’s hardness flexibility makes it a reliable material for industries that demand strength and adaptability—without breaking the budget.