典型的精密锻造技术Typical precision forging technology

精密锻造是指零件锻造成形后，只需少量加工或不再加工即符合零件尺寸精度要求的成形技术。实现精锻成形的途径主要有两种：精化毛坯，即直接锻造出满足精密机加要求的毛坯。精锻件，整个或零件一些部分直接采用精锻工艺加工而成，从而减少机加量。目前应用于生产的精密锻造工艺很多。按成形温度不同可以分为热精锻、冷精锻、温精锻、复合精锻等。

1、热精锻工艺

热精锻是指在再结晶温度以上进行锻造的精锻工艺。因为变形温度高，在进行锻造时材料的变形抗力低，塑性好，所以易于成形几何形状复杂的零件。

2、冷精锻工艺

冷精锻工艺是在室温下进行锻造的一种精锻成形技术。由于室温成形，避免由于热胀冷缩带来的尺寸误差，所以冷精锻的工件形状和尺寸较易控制，同时锻件表面不产生氧化和烧损等，具有较高的表面质量，因此热精锻与温精锻的锻造精度均比冷精锻要低。

3、温精锻工艺

温锻是把金属加热到再结晶温度以下适合的温度进行锻造的一种精锻技术。它同时具有热锻、冷锻的优点而避免了它们的缺陷，有效地降低了设备与模具的载荷，提高了金属的塑性和流动性，不需锻退火。

4、复合精锻工艺

复合精锻工艺将冷、温、热锻工艺进行组合共同完成一个工件锻造的一种锻造技术，它能发挥冷、温、热锻的优点，避免了冷、温、热锻的缺点。同时采用复合精锻工艺生产的零件其机械性能、尺寸精度、表面质量较采用单一锻造技术生产的零件都有所提高。目前常用的复合精锻工艺主要有温锻－ 冷精整、热锻－ 冷锻、温挤压－ 冷摆辗、温热精锻－ 冷挤压、热精锻－ 冷摆辗等。

Precision forging refers to the forming technology that only needs a small amount of processing or no longer processing to meet the dimensional accuracy requirements of the parts after the parts are forged and formed. There are two main ways to achieve precision forging forming: refining the blank, that is, directly forging the blank that meets the requirements of precision machining. Precision forgings, the whole or some parts of the parts are directly processed by the precision forging process, so as to reduce the amount of machining. At present, there are many precision forging processes used in production. According to the different forming temperatures, it can be divided into hot precision forging, cold precision forging, warm precision forging, composite precision forging, etc.

1. Hot precision forging process

Hot precision forging refers to the precision forging process that is forged above the recrystallization temperature. Because of the high deformation temperature, the deformation resistance of the material during forging, and the good plasticity, it is easy to form parts with complex geometries.

2. Cold precision forging process

Cold precision forging is a precision forging forming technology that is forged at room temperature. Due to the room temperature forming, to avoid the size error caused by thermal expansion and contraction, the shape and size of the workpiece of cold precision forging are easy to control, and the surface of the forging does not produce oxidation and burning, etc., and has a high surface quality, so the forging accuracy of hot precision forging and warm precision forging is lower than that of cold precision forging.

3. Warm precision forging process

Warm forging is a precision forging technology in which the metal is heated to a suitable temperature below the recrystallization temperature. It has the advantages of hot forging and cold forging at the same time to avoid their defects, effectively reduce the load of equipment and molds, improve the plasticity and fluidity of metal, and do not need forging annealing.

4. Compound precision forging process

Composite precision forging process is a forging technology that combines cold, warm and hot forging processes to complete a workpiece forging, which can give full play to the advantages of cold, warm and hot forging and avoid the shortcomings of cold, warm and hot forging. At the same time, the mechanical properties, dimensional accuracy and surface quality of the parts produced by the composite precision forging process are improved compared with the parts produced by the single forging technology. At present, the commonly used composite precision forging processes mainly include warm forging - cold finishing, hot forging - cold forging, warm extrusion - cold swing rolling, warm precision forging - cold extrusion, hot precision forging - cold swing rolling, etc.