Hard Gear Surface and Soft Gear Surface

According to the hardness of gear surface, the forged steel is divided into two categories, which are soft gear surface, HB＜350; and hard gear surface, HB＞350.

Hard gear surface

1. Process: Forging roughcast - normal - rough cutting - quenching and tempering - fine cut -high, intermediate frequency quenching - low temperature tempering - honing or abrasive running-in, electrospark running-in.

2. Common used materials: 45,40Cr, 40CrNi.

3. Features: High gear surface hardness, high contact strength and good wear resistance. Tooth core maintains the good toughness after quenching and tempering, excellent impact resistance, high loading capacity. The cutting precision is up to level-7. It is applicable to mass production, such as the automotive shift system parts, machine tools and others.

Soft gear surface

1. Process: Forging roughcast - normalizing, roughing - quenching and tempering, finishing.

2. Commonly used materials: 45 #, 35SiMn, 40Cr, 40CrNi, 40MnB.

3. Features: The soft gear surface has a good overall performance. The gear surface with high strength and hardness, and tooth core in a better toughness. The cutting precision is up to level-8 after heat treatment. It features simple manufacturing, very economical and high productivity, as well as the accuracy isn't high.