Recent years, NNN bearing had carried out a deep research on the bearing steel water solvent quenching and achieved a excellent result. We had quenched thousands of bearing parts with water solvent, the quality is always reliable, and there is no negative feedback from customers. After a long time of production and inspection of the bearings part quenched by water solvent, it proved that water solvent quenching is far better than the traditional oil quenching, the advantages are shown as below:
1. The heat treatment quality of bearing steel after water solvent quenching is more excellent than the traditional oil quenching. Through many times random inspection , according to bearing industry heat treatment quality standard JB/T1255 , after water solvent quenching ,the microstructure are all the excellent 2-3 grade martensite structure, the unqualified microstructure and hardness never appeared. Especially for the extra-thick GCr15 steel part, over a certain range ,if choose the oil quenching , the specifications of micro-structure and hardness cannot meet the requirements of bearing industry heat treatment quality standard JB/T1255, but the water solvent quenching can solve this problem well. What is more, the harden case of extra-thick GCr15 steel products are apparently deeper than the oil quenching, in this way , it will improve the loading capacity of bearing parts.
2. The strength of bearing steel after water solvent quenching is more excellent than the traditional oil quenching. After professional mechanic property inspection, water quenching bearing parts has a higher crushing load capacity than oil quenching, the hardness is higher also. Take diameter 40mm cylindrical roller made of GCr15 steel for example, after oil quenching, hardness is 61 HRC, crushing load is 1247.2KN. However, after water solvent quenching, the hardness is 62 HRC, crushing load is bigger than 1400KN.
The advantage of quality and property of water solvent quenching is mainly from the reasonable technique. Applying the excellent cold performance of water solvent, can reduce the austenitizing temperature of bearing steel. In this way, it will lower the concentration of carbon which dissolved to matrix and finally get the low-carbon martensite. The sub-structure of the martensite is dislocation, not only have high hardness, but also possess good tenacity.