Effect of Shot Peening on Microstructures and High‐Temperature Tribological Properties of 4Cr9Si2 Valve Steel. Issue 11 (21st August 2021)

• Record Type: Journal Article
• Authors: Jia, Siyu; Qu, Shengguan; Hu, Xiongfeng; Lai, Fuqiang; Duan, Chenfeng; Li, Xiaoqiang
• Is Part Of: Steel research international. Volume 92:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-21
• Subjects: elevated temperatures -- engine valve steels -- microstructures -- shot peening -- tribological behaviors; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.202100250
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : Herein, shot peening (SP) using different parameters is performed on 4Cr9Si2 martensite engine valve steel at elevated temperatures. The microstructure of the modified layer is characterized via optical microscopy (OM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). High‐temperature wear tests are performed under dry sliding conditions at 450 °C using a pin‐on‐disc wear tester, and the worn surface is evaluated via scanning electron microscopy (SEM) and energy‐dispersive spectroscopy (EDS). The results show that SP refines the grains on the top surface to 19.8 nm and yields numerous dislocations. Meanwhile, the compressive residual stress and microhardness of the treated surface increase to −575 MPa and 486.33 HV0.2, respectively. At elevated temperatures, the increase in hardness provides resistance to plastic deformation and improves the performance of the oxide film. Compared with an untreated sample, sample SP4 shows a 65.23% decrease in wear rate and its wear resistance improves significantly at elevated temperatures. In addition, the wear mechanisms of SP‐treated samples are primarily oxidation wear and delamination. Abstract : Herein, valve steel 4Cr9Si2 is subjected to shot peening (SP) using different processing parameters. SP yields numerous dislocations, refines the grains, introduces residual stresses, and increases microhardness, which is vital to the tribological behaviors. Under the positive effects of SP, sample SP4 shows the lowest wear rate and the best wear resistance at elevated temperatures.