AISI 1045 medium carbon steel

Jul 5, 2012

Image credits: kwanchei / shutterstock.com

AISI 1045 steel is a medium strength steel supplied in a hot rolled or normalized black condition. It has a tensile strength of 570-700 MPa and a Brinell hardness of 170-210.

AISI 1045 steel is characterized by good weldability, good machinability and high strength and impact properties in the normalized or hot rolled state.

AISI 1045 steel has a low through-hardening capacity, only sections of around 60mm are recommended for through-hardening and hardening. However, it can be effectively flame or induction quenched in standard state or hot rolled to achieve surface hardnesses between Rc 54 and Rc 60 depending on factors such as section size, type of mounting, the quenching medium used, etc.

AISI 1045 steel lacks suitable alloying elements and therefore does not respond to the nitriding process.

Chemical composition

Physical properties

Mechanical properties

Machining

AISI 1045 steel has good machinability in normalized or hot rolled condition. Based on the recommendations given by machine manufacturers, operations such as tapping, milling, broaching, drilling, turning and sawing can be performed on AISI 1045 steel using feeds, types of ‘appropriate tools and speeds.

Welding

AISI 1045 steel is easily welded when the correct procedure is followed, but welding of AISI 1045 steel under through hardening, tempering and flame or induction hardening conditions is not recommended. Low hydrogen electrodes are preferred for welding AISI 1045 steel.

The part is:

• preheated to 200 ° C-300 ° C (392 ° F – 572 ° F);
• maintained at the same temperature during welding;
• cooled slowly with sand or ash; and
• expanded to 550 ° C – 660 ° C (1022 ° F – 1220 ° F).

Heat treatment

AISI 1045 undergoes forging, annealing, normalizing, stress relieving, hardening and tempering processes, each of which is explained in more detail below:

• Forging – Heat to 850 ° C – 1250 ° C (1562 ° F – 2282 ° F). Hold until temperature is uniform. Cool in an oven.
• annealing – Heat to 800 ° C – 850 ° C (1472 ° F – 1562 ° F). Hold until temperature is uniform. Cool in an oven.
• Normalize – Heat to 870 ° C – 920 ° C (1598 ° F-1688 ° F). Hold until temperature is uniform. Soak for 10 to 15 minutes. Cool in still air.
• Stressful – Heat to 550 ° C – 660 ° C (1022 ° F – 1220 ° F). Hold until temperature is uniform. Soak for 1 hour in 25 mm increments. Cool in still air.
• Hardening – Heat to 820 ° C – 850 ° C (1508 ° F – 1562 ° F). Hold until temperature is uniform. Soak for 10 to 15 minutes per 25mm section. Soak in water or brine.
• Hardening – Heat to 400 ° C – 650 ° C (752 ° F – 1202 ° F) as needed. Hold until temperature is uniform. Soak for 1 hour in 25 mm increments. Cool in still air.

Applications

AISI 1045 is widely used for all industrial applications requiring more wear resistance and strength. Typical applications of AISI 1045 are as follows:

This article was updated on 7^e August 2019.