1. When such a quenched steel is tempered, structures with mechanical properties intermediate between those of the slowly cooled and the quenched conditions are formed.

2. The cutting experiments show that in cutting of quenched steel the tool life of this cutter is longer than that of uncoated cutting tool.

3. Grind - hardening of non - quenched steel was performed with creep feed grinding mode and different cooling conditions. Microstructure and properties of the surface hardened layer were compared.

4. The hardness data of quenched steel under different conditions were collected utilizing austempering tests.

4. try its best to collect and create good sentences.

5. The mechanism of cutting force, cutting temperature and tool wear in the machining of quenched steel and nickel based high temperature alloy with ceramic tools are analyzed in the paper.

6. The results show that, in cutting teat, best cutting speed exists for different quenched steel.

7. The grinding force ratio in grind-hardening consists with the grinding force ratio in grinding quenched steel, and is bigger than the grinding force ratio in grinding unquenched steel.

8. The test has been demonstrated that the boron segregation at austenite grain boundaries in quenched steel is a non-equilibrium grain boundary segregation phenomena occurred during cooling.

9. An analytical function for describing hardness distribution in round section of quenched steel, known as U-curve, has been established.

10. Although the present study limits to two-passes grinding, the forming mechanism of the hardened layer is applicable to grind-hardening of multi-passes or quenched steel.

11. It has been demonstrated that the boron segregation at austenite grain boundaries in quenched steel is a non-equilibrium grain boundary segregation phenomena occurred during cooling.