Ultra-high strength steel is a kind of alloy steel used to make structural parts under high stress. General flexural strength is greater than 1180MPa, tensile strength is greater than 1380MPa this kind of steel generally has enough toughness and high specific strength and flexural ratio, and good weldability and formability. According to alloying degree and microstructure, it can be divided into low alloy, medium alloy and high alloy ultra-high strength steels. When grinding ultra-high strength steel, the grinding force, grinding temperature and grinding surface quality of workpiece will be greatly affected by the grinding amount. Increasing the grinding wheel speed can decrease the grinding force but increase the grinding temperature.
With the increase of grinding depth, the grinding force and grinding temperature increase, and the workpiece is easy to produce grinding burn. The residual tensile stress of grinding surface increases with the increase of grinding wheel speed and grinding depth.
Therefore, when grinding ultra-high strength steel, the grinding amount should be slightly smaller, the grinding wheel speed is generally not more than 30m/s, the grinding depth is generally less than 0.02mm, the fine grinding depth α ≤0.01mm.
(1) Cylinder grinding
* The grinding wheel speed is (20 ~ 28)m/s.
* The workpiece velocity is (20 ~ 30)m/min.
* The grinding depth of coarse grinding is 0.02mm, the grinding depth of fine grinding is 0.01mm;
* The longitudinal feed of the workpiece is (1/8 ~ L / 4)Bmrn/r, and a small value is taken during fine grinding.
(2) Internal grinding
---Grinding wheel speed (20 ~ 30)m/s.
---The workpiece speed is (20 ~ 28)m/min, the grinding depth is (0.05 ~ 0.01)mm/DST, and the longitudinal feed is (1/6 ~ L / 3)Bmm/r
(3) Surface grinding
* The grinding wheel speed is (15 ~ 30)m/s.
* Table speed (15-25) rn/min.
* Grinding depth is (0.01 ~ 0.025)mm, small value when fine grinding.
* The horizontal feed is (1/10 ~ 1/4)Bmm/DST.
For grinding ultra-high strength steel grinding fluid, water based grinding fluid with high thermal conductivity should be used. It is better to reduce grinding temperature, reduce and prevent burns.
----EDITOR:Anna Wang/Doris Hu