柴油机用304L不锈钢高压油管内挤压研究

Study on High Pressure Fuel Pipe Squeeze in Diesel Engine

针对某型号柴油机用304L不锈钢高压油管出现开裂漏油的问题,采用内挤压法对管内表面经780MPa油压、保压125s的内挤压处理后,使其0￣50μm非致密层发生强烈塑性形变,晶格严重畸变导致很强的加工硬化效应,使内表层维氏硬度比内层高得多,改善了管材内表层的抗疲劳性能,显著提高了管材抗高压脉动油产生的疲劳载荷的能力,大幅延长了高压油管的使用寿命。

Seeing that the leak problem of the stainless steel high pressure fuel pipe for the crack in the diesel engine always appears, the ＂squeeze＂ treatment for the fuel pipes was conducted. The results are as follows： After treatment with high pressure at 780 MPa/2 min ＋5 s （rapid pressure relief） , the plastic deformation occurred to the inner surface of 304L austenitic stainless steel pipe, of which the deformation area is mainly distributed on the loose layer from 0-20 mm of the inner surface. As a result, as compared with the pipe without treat- ment the microhardness increases by 21 N/mm, the tensile strength increases 10 MPa, the elongation decreases by 2.7%, and the fatigue strength increases obviously, which the quality of the inner surface of the pipes is improved and the working life is tracted..