Causes of low hardness of motorcycle chain wheel and its elimination

The causes are: low carbon content in gear steel; improper selection of quenching heating process, low heating temperature or insufficient holding time; surface decarburization; insufficient quenching cooling; high tempering temperature; improper material selection. Countermeasures to test the chemical composition of steel; adjust the quenching process, appropriately increase the quenching heating temperature or increase the holding time; replace the steel.