August 2024 Volume 6

MATERIALS

TAKE CARE OF YOUR TOOLS The Importance & Benefits of Heat Treating Your Forging Dies By FIA Staff

H eat treating forging dies is crucial for ensuring both the quality of forged parts and the longevity of the dies them selves. Dies are specialized tools used to shape hot metal into desired geometry through high-pressure forging. What makes die materials different than forging materials? Forging dies are subjected to similar conditions to the material being forged. Die material selection must consider the desired life of the die due to the same repeated conditions of: • High temperature. • High pressure. Therefore, the class of alloys for forging dies are designed to have: • High strength/resistance to plastic deformation. • High toughness. • The ability to harden uniformly. • Good wear resistance. • Resistance to thermal fatigue. • Resistance to mechanical fatigue. • Resistance to softening.

Here’s why heat treating these dies is so important: 1. Hardness and Wear Resistance: Dies are subjected to extreme conditions during forging, including high temperatures and pressures. Heat treating, typically through processes like quenching and tempering, increases the hardness of the die material. This hardness is essential for withstanding the repeated impact and abrasion from hot metal during forging operations. A harder die surface resists wear better, prolonging the die's life and maintaining the dimensional accuracy of forged parts over time. 2. Toughness and Strength: While hardness is crucial, excessive brittleness can lead to failure of the die under the intense pres sures of forging. Proper heat treatment not only enhances hard ness but also optimizes toughness and strength. This balance is achieved through controlled heating and cooling processes that transform the microstructure of the die material, ensuring it can absorb the shock and stress of forging without fracturing.

Figure 2: Toughness and harness in relation to temperature [4]. 3. Dimensional Stability: During heat treatment, dies are care fully heated and cooled to minimize distortion and maintain dimensional stability. Precision in the shape and dimensions of the die is critical because any deformation or warping can affect the accuracy and consistency of the forged parts produced. Heat treatment helps to control these changes, ensuring that the die retains its shape and dimensions throughout its life.

Figure 1: Heat treatment cycle of hot work tool steels [1].

FIA MAGAZINE | AUGUST 2024 36