What are the different phases a C1045 Steel goes through at

What are the different phases a C1045 Steel goes through at autenitizing, tempering, and spheriodizing process of heat treatment?

Solution

C1045 is a medium carbon, medium tensile steel supplied as forged or normalized. This steel shows good strength, toughness and wear resistance. C1045 will through harden to 2.5” (63mm) with a tensile strength of 66 – 120 Ksi (620 – 850 MPa).

C1045 is forged from 2100 – 2300 º F (1150 – 1280 º C) down to a temperature in the range1600 – 1700 º F (870 – 925 º C.). The actual forging and finishing temperatures will depend on a number of factors, including overall reduction during forging and complexity of part being forged. Experience alone will determine near exact values for these two parameters. Parts are air cooled after forging.

HEAT TREATMENT

Heat treatment is carried out on this grade to render it suitable for machining and to impart to it specified mechanical properties.

ANNEALING

Full annealing of small C1045 forgings is carried out between 1450 and 1600 º F (790 – 870 º C) followed by furnace cooling at 50 º F (10 º C) per hour, to 1200 º F (650 º C) and air cooling.

NORMALIZING

The normalizing temperature range for this grade is typically 1550 – 1600 º F (840 – 870 º C,) Normalizing is followed by cooling in still air. When forgings are normalized before hardening and tempering or other heat treatment, the upper range of the normalizing temperature is used. When normalizing is the final treatment, the lower temperature range is used.

HARDENING

Hardening of this grade is carried out from an austenitizing temperature of 1510 – 1580 º F (820 – 860 º C) and oil or water quenching.

Flame and induction hardening may be carried out by heating quickly to the desired case depth and quenching in water or oil. This should be followed by a tempering treatment at 300 – 400 º F (150 – 200 º C) to reduce stresses in the case without affecting its hardness. A surface hardness of Rc 58 may be obtained by this treatment.

TEMPERING

Tempering after normal hardening and oil or water quenching is carried out at 750 – 1260 º F (400 – 680 º C) to give the required mechanical properties as determined by practical experience.

MACHINABILITY

Machinability of C1045 is good providing the full annealing cycle described above is used, ensuring a coarse lamellar pearlite to coarse spheroidite microstructure.

WELDABILITY

This grade is readily welded with the correct procedure. Welding in the through hardened or flame or induction hardened conditions is not recommended.

Low-hydrogen electrodes are recommended together with preheat at 400 – 570 º F (200 – 300 º C.) , to be maintained during welding, Cool slowly in sand or ashes and stress relieve where possible.