Heat treatment process generally includes heating, heat preservation, cooling three processes, sometimes only heating and cooling two processes. These processes are linked to each other and cannot be continuous.

加热是热处理的重要工序之一。金属热处理的加热办法许多，是选用木炭和煤作为热源，进而运用液体和气体燃料。电的运用使加热易于操控，且无环境污染。运用这些热源能够直接加热，也能够经过熔融的盐或金属，以致起浮粒子进行直接加热.金属加热时，工件暴露在空气中，常常发作氧化、脱碳(即钢铁零件外表碳含量下降)，这关于热处理后零件的外表功能有很不利的影响。因而金属通常应在可控气氛或维护气氛中、熔融盐中和真空中加热，也可用涂料或包装办法进行维护加热。

Heating is one of the important processes of heat treatment. There are many heating methods for metal heat treatment. Charcoal and coal are selected as heat sources, and then liquid and gas fuels are used. The use of electricity makes heating easy to control and has no environmental pollution. When the metal is heated, the workpiece is exposed to the air, and often occurs oxidation and decarburization (that is, the carbon content on the surface of steel parts decreases), which has a very adverse effect on the surface function of the parts after heat treatment. Therefore, the metal should be heated in controllable atmosphere or maintenance atmosphere, molten salt and vacuum, and can also be maintained and heated by coating or packaging.

加热温度是热处理工艺的重要工艺参数之一，挑选和操控加热温度，是确保热处理质量的首要问题。加热温度随被处理的金属材料和热处理的意图不同而异，但一般都是加热到相变温度以上，以取得高温安排。另外改动需求必定的时刻，因而当金属工件外表到达要求的加热温度时，还须在此温度保持必定时刻，使表里温度共同，使显微安排改动彻底，这段时刻称为保温时刻。选用高能密度加热和外表热处理时，加热速度极快，一般就没有保温时刻，而化学热处理的保温时刻往往较长。

Heating temperature is one of the important process parameters of heat treatment process. Selecting and controlling the heating temperature is the primary problem to ensure the quality of heat treatment. The heating temperature varies with the metal material to be treated and the intention of heat treatment, but it is usually heated above the phase transition temperature to obtain high temperature arrangement. In addition, the change needs a certain time. Therefore, when the surface of the metal workpiece reaches the required heating temperature, it is necessary to maintain a certain time at this temperature, so that the temperature inside and outside of the metal workpiece can be changed completely. This time is called the holding time. When high-energy density heating and surface heat treatment are used, the heating speed is very fast, and there is generally no holding time, while the holding time of chemical heat treatment is often longer.

冷却也是热处理工艺进程中不行短少的过程，冷却办法因工艺不同而不同，首要是操控冷却速度。一般退火的冷却速度慢，正火的冷却速度较快，淬火的冷却速度更快。但还因钢种不同而有不同的要求，例如空硬钢就能够用正火一样的冷却速度进行淬硬。

Cooling is also an indispensable process in the process of heat treatment. The cooling methods vary with different processes, and the first is to control the cooling rate. Generally, the cooling rate of annealing is slow, that of normalizing is faster than that of quenching. However, there are different requirements due to different steel grades. For example, air hardened steel can be hardened at the same cooling rate as normalizing.