45 steel and 55 steel quenching on mesh belt furnace as heat treatment process

45 steel and 55 steel can be quenched (quenched and tempered) in roller furnace and mesh belt furnace

1. S45cc is a Japanese steel grade, equivalent to 45 steel in China

China's 45 steel, is medium carbon steel, carbon content is about 0.45%

2. After quenching and before tempering, the hardness of 45 steel is higher than HRC55 (up to HRC62)

The highest hardness in practical application is HRC55

3. The heat treatment process of carburizing and quenching should not be used for 45 steel

The hardness of quenched and tempered parts of 45 steel should reach hrc56 ~ 59, and the possibility of large cross-section is lower, but it can not be lower than hrc48. Otherwise, it means that the workpiece has not been fully quenched, sorbite and even ferrite may appear in the structure. This kind of structure still remains in the matrix after tempering, which can not achieve the purpose of quenching and tempering

4. After quenching and tempering, the high temperature tempering temperature of 45 steel is usually 560 ~ 600 ℃, and the hardness requirement is hrc22 ~ 34. Because the purpose of quenching and tempering is to obtain comprehensive mechanical properties, the hardness range is relatively wide. However, if there are hardness requirements in the drawing, the tempering temperature should be adjusted according to the drawing requirements to ensure the hardness, However, some gears and shafts with keyway require lower hardness due to milling and inserting after quenching and tempering. According to the tempering holding time, it depends on the hardness requirements and the size of the workpiece. In my opinion, the hardness after tempering depends on the tempering temperature and has little to do with the tempering time, but it must be penetrated back. Generally, the tempering holding time of workpieces is more than one hour

5. 45 steel belongs to medium carbon steel, which is a high-quality carbon structural steel, and its quenching hardness is less than 55-62hrc. As shaft parts, the general process is quenching and tempering. Even if the surface needs hardness, it does not need the whole hardness to be as high as that. It only needs to harden the surface

6. The quenching and tempering hardness of 45 steel is between hrc20 and hrc30, and the quenching hardness of 45 steel is between HRC55 and 58, and the limit value can reach HRC62. The highest hardness applied is HRC55 (high frequency quenching hrc58). 45 steel can only be used for 15-20 days because aging treatment is needed to stabilize the properties of steel

7. The heat treatment process of carburizing and quenching should not be used for 45 steel. After quenching and tempering, the parts have good comprehensive mechanical properties and are widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts working under alternating load. However, the surface hardness is low and it is not wearable. The surface hardness of parts can be improved by quenching and tempering and surface quenching