为了能钻φ20～50毫米的深孔,我们特地将钻头接长,接长的长度由孔深而定(接长部位如图所示)。钻头材质为高速工具钢W18Cr 4V,接柄材质为45钢,这两种材料的可焊性较差。为此,我们制定了焊前预热和焊后热处理的焊接工艺,使高速工具钢与45钢焊接后的使用性能良好。现将工艺介绍如下。 In order to be able to drill deep holes of φ20 ~ 50mm, we specially connect the drill bit long, then the length of the long hole is determined by the hole depth (the long part is as shown in the figure). The drill is made of high-speed tool steel W18Cr 4V and the stem is made of 45 steel, which is less solderable. To this end, we have developed a pre-welding and post-weld heat treatment of welding process, the high-speed tool steel and 45 steel welding performance after the use of good. The process is as follows.