Why most of the connecting rods are drop forged?


 it makes us wonder what it is! Why do manufacturers want you to know that a it is drop forged?

Striking a piece of hot metal with a hammer is forging, and blacksmiths have been doing this for centuries. As blacksmiths experimented with new techniques, they learned that complex shapes could be created by hammering metal into a die. The die contains the shape of the finished product. Modern manufacturers use either a falling hammer or a powered hammer to do the hammering (rather than doing it by hand), and usually use dies on both sides of the piece. This is drop forging.

Drop forging is a metal shaping process, the metal to be formed is first heated then shaped by forcing it into the contours of a die, this force can be in excess of 2000 tons. The drop forging process can be performed with the material at various temperatures;
  • >Hot Forging
    During hot forging the metals are heated to above their recrystallization temperature. The main benefit of this hot forging is that work hardening is prevented due to the recrystallization of the metal as it begins to cool.

  • >Cold Forging
    Cold Forging is generally performed with metal at room temperature below the the recrystallization temperature. Cold forging typically work hardens the metal.

The reason why manufacturers want you to know that a tool is drop forged is because this tells you something about the strength and durability of the tool. The other two ways to make a tool would be casting it from molten metal or machining it (cutting material away) from a larger block of metal. The advantage of forging is that it improves the strength of the metal by aligning and stretching the grain structure. A forged part will normally be stronger than a casting or a machined piece.

The impact forces applied during forging forces the downscaling of the gains in terms of size. Smaller grain sizes are associated with better strength. This is the reason why components expected to undergo severe service conditions, like connecting rods, are forged.


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