若因溫度和變形程度選擇不當(dāng)而得到粗大晶粒時(shí)，可利用熱處理相變細(xì)化晶粒組織，但對(duì)于熱處理中不發(fā)生相變的鋼種，如奧氏體鋼，就必須在鍛造過(guò)程中獲得細(xì)小而均勻的晶粒組織，因此對(duì)這樣的材料在鍛造時(shí)須加倍注意。

If the temperature and degree of deformation and improper selection of coarse grains, the grain refinement phase change heat treatment, but for the steel phase transition does not occur in the heat treatment, such as austenitic steel, it must be in the forging process have fine and uniform grains, so this kind of material in the forging must pay more attention to.

鍛造是指把加熱后的金屬材料鍛制成各種形狀的工具、機(jī)械零件或毛坯。鍛造過(guò)程中要對(duì)這些滾燙的金屬坯料進(jìn)行各種加工，因此加工過(guò)程中高溫、、振動(dòng)和噪聲是避免不了的。所以鍛造過(guò)程安全防護(hù)很重要。

Forging is a tool, mechanical part, or blank that is forged from a heated metal material to a variety of shapes. In the process of forging, these hot metal billets should be processed, so high temperature, dust, vibration and noise can not be avoided during the process. Therefore, the safety protection of the forging process is very important.

在現(xiàn)代工業(yè)生產(chǎn)中，機(jī)器自由鍛已成為鍛造生產(chǎn)的主要方法，在重型機(jī)械制造中，它具有特別重要的作用。而產(chǎn)生的鍛件形狀和尺寸主要由操作工的技術(shù)水平?jīng)Q定。

In modern industrial production, machine free forging has become the main method of forging production, and it plays a particularly important in heavy machinery manufacturing. The shape and size of the forgings are mainly determined by the technical level of the operator.

在芯棒上拔長(zhǎng)。鍛造時(shí)，先芯棒插入沖好孔的坯料中，然后當(dāng)作實(shí)心坯料進(jìn)行拔長(zhǎng)。拔長(zhǎng)時(shí)，一般不是一次拔成，先將坯料拔成六角形，鍛到所需長(zhǎng)度后，再倒角滾圓，取出芯棒。為便于取出芯棒，芯棒 的工作部分應(yīng)有1：100 左右的斜度。

Pull on the mandrel. When forging, insert the mandrel into the billet of the hole and then pull it out as a solid billet. When drawing, it is not usually drawn at one time. First, the blank is drawn into a hexagonal shape, forged to the required length, then chamfered and rounded, and the mandrel is removed. To facilitate the removal of the mandrel, the working part of the mandrel should have a slope of about 1:100.