according toHard tooth surface gear reducerTooth surface hardness is usually divided into two types of gear transmission, namely hard-tooth surface gear transmission and soft-tooth surface gear transmission.  
    Usually, the tooth surface hardness of a pair of meshing gears is greater than 350HBS, which is called hard surface gear, otherwise it is called soft surface gear.  
    According to the hardness of the tooth surface, people usually divide gear transmission into two types, namely, hard tooth surface gear transmission and soft tooth surface gear transmission.The choice of gear transmission should be based on the design requirements. The two gear transmissions have their own advantages and disadvantages, but they have large hard tooth surface transmission loads, long service life, and wide applications.  
    Hard tooth surface gear reducerThere are many materials and heat treatment methods used, such as several commonly used: 40Cr. 45#.45Mn2 steel can be final heat treated high frequency tempering or nitriding treatment, such as 20Cr.20CrMnTi.20CrMnVB.20CrNiH, etc., can be carburized and quenched, such as 38CrMnAl can use nitriding process to achieve higher hardness, and some special materials need special heat treatment methods.

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