图1所示的气阀座是铁路东风4型内燃机车柴油机进排气机构中的一个重要零件,其材质为Cr12MoV。过去采用自由锻工艺生产效率低,余最大。我们本着一坯多件的构思(见图2),结合现场生产条件并经反复试验后,将工艺改进为φ60棒料加热至600～700℃→自由锻锤→剪切下料→再加热至1100℃→1150℃→1吨自由锻锤镦粗制坯(图3)→再加热至略低于1100℃→1000吨摩擦压力机热反挤成杯形件→冲孔→锻后退火。反挤压与冲孔模具如图4所示。为使模具简单可靠,冲孔采用简单的活动式冲头。Cr12MoV是一种莱氏体合金钢,含有较高的 The valve seat shown in Fig. 1 is an important part of the diesel engine intake and exhaust mechanism of the DF-4 diesel locomotive. Its material is Cr12MoV. The past, the use of free forging production of low efficiency, the largest remaining. In line with the concept of a blank piece (see Figure 2), combined with the production conditions in the field and after repeated tests, the process was improved to 60 bar φ60 heated to 700 ℃ → free forging hammer → shear cutting → reheating To 1100 ℃ → 1150 ℃ → 1 ton of free forging hammer upsetting billet (Figure 3) → reheating to slightly below 1100 ℃ → 1000 tons of friction press hot anti-extrusion into a cup → punching → annealing after forging. Anti-extrusion and punching die shown in Figure 4. In order to make the mold simple and reliable, punching using a simple movable punch. Cr12MoV is a ledeburite alloy steel, containing higher