本书以传统的电渣重熔法冶炼超硬高速钢获得最初铸锭为起点开始研究，通过thermo-calc软件计算高速钢凝固冷却过程中各相在平衡态和非平衡态条件下的析出温度，分析了锻造、退火、淬火、回火各级热处理工艺对M42高速钢微观组织和力学性能的影响；采用高温共聚焦扫描激光显微镜对高速钢淬火升温和冷却过程组织变化进行原位观察，并分析冷却速率对微观结构的影响；研究了奥氏体化温度和保温时间对碳化物的影响；研究了回火时间对M42高速钢中碳化物特性和长大的影响；通过对不同氮含量高速钢试样进行显微组织观察，研究了氮含量对M42高速钢微观组织及碳化物的影响。

Chapter 1 Thermodynamic Analysis of Carbide Precipitation during Solidification of M42 High-Speed Steel
1.1 Introduction
1.2 Thermodynamic calculation of M2C carbide precipitation in equilibrium state
1.3 Thermodynamic calculation of carbide precipitation in non- equilibrium state
1.4 Conclusions
References
Chapter 2 Microstructure Evolution in M42 High-Speed Steel during ESR and Hot Deformation
2.1 Introduction
2.2 Experimental section
2.2.1 Material
2.2.2 Compression simulation test
2.2.3 Microstructure characterization
2.2.4 Calculation of mechanical properties of carbides
2.3 Results and discussions
2.3.1 As-cast and wrought microstructures
2.3.2 Mechanical properties of the carbides
2.3.3 Stress-strain curves and microstructure evolution
2.3.4 Microstructure evolution
2.4 Conclusions
References
Chapter 3 Effects of Austenitizing Conditions on the Microstructure of M42 High-Speed Steel
3.1 Introduction
3.2 Experimental section
3.3 Results and discussions
3.3.1 Phase transformation and precipitation behavior of carbides
3.3.2 Effects of austenitizing temperature on microstructure and properties
3.3.3 Effects of austenitizing time on microstructure and properties
3.3.4 Effects of cooling rate on microstructure and properties
3.4 Conclusions
References
Chapter 4 Effect of Cooling Rate on the Transformation Characteristics and Precipitation Behaviour of Carbides in M42 High-Speed Steel
4.1 Introduction
4.2 Experimental sections
4.2.1 Material
4.2.2 Experimental procedure
4.2.3 Microstructural characterization
4.2.4 Hardness testing
4.3 Results and discussion
4.3.1 Precipitates formation in M42 high-speed steel at equilibrium
4.3.2 Microstructure of as-cast M42 ESR ingot
4.3.3 Microstructural transformation in M42 high-speed steel under continuous cooling conditions
4.3.4 Precipitation behaviour of carbides in M42 high-speed steel under continuous cooling conditions
4.4 Conclusions
References
Chapter 5 Microstructure and Mechanical Properties of M42 High-Speed Steel during Tempering Process
5.1 Introduction
5.2 Experimental sections
5.2.1 Material
5.2.2 Microstructural characterization
5.2.3 Mechanical property measurement
5.3 Results
5.3.1 Microstructure of the quenched M42 HSS before tempering
5.3.2 Microstructure of the tempered M42 HSS
5.3.3 Mechanical properties
5.4 Discussion
5.4.1 Effects of tempering time on the characteristics and growth of carbides
5.4.2 Effects of tempering time on the transformation of martensitic matrix and yield strength
5.4.3 Effects of tempering time on mechanical properties of M42 HSS
5.5 Conclusions
References
Chapter 6 Influence of the Nitrogen Content on the Carbide Transformation of M42 High-Speed Steels during Annealing
6.1 Introduction
6.2 Experimental procedures
6.2.1 Material and specimen preparation
6.2.2 Annealing treatment
6.2.3 Microstructural analysis
6.2.4 Carbide collection and analysis
6.2.5 Impact toughness testing
6.3 Results and discussions
6.3.1 Precipitate formation in M42 HSS calculated using thermo-calc based on different nitrogen content
6.3.2 Effect of nitrogen as an alloying element on the as-cast structure
6.3.3 Effect of nitrogen on the carbide transformation and impact toughness of annealed steel
6.4 Conclusions
References