| MA Yongtao,ZHANG Yuejiang,LIU Lanrong,LI Chunfan,SUN Wanshun,SUN Baocheng.Mechanism and Experimental Study of Pre-mixed Water Jet Composite Shot Peening[J],54(9):225-238 |
| Mechanism and Experimental Study of Pre-mixed Water Jet Composite Shot Peening |
| Received:August 26, 2024 Revised:December 18, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.09.019 |
| KeyWord:pre-mixed water jet secondary shot peening micro shot peening roughness residual stress saturated residual stress field |
| Author | Institution |
| MA Yongtao |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China;Industrial Science & Technology Institute for Anti-fatigue Manufacturing, Zhengzhou , China |
| ZHANG Yuejiang |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China |
| LIU Lanrong |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China;Industrial Science & Technology Institute for Anti-fatigue Manufacturing, Zhengzhou , China |
| LI Chunfan |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China |
| SUN Wanshun |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China |
| SUN Baocheng |
School of Mechanical and Power Engineering,Henan Province Engineering Research Center of Anti-fatigue Manufacturing Technology, Zhengzhou University, Zhengzhou , China |
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| Abstract: |
| High surface integrity plays a key role in determining the performance of basic components such as gears. As a high-quality gear steel, 18CrNiMo7-6 carburized steel has become a focus of engineering and academic research for surface treatment to improve fatigue performance. Composite water jet shot peening (WJSP) improves the fatigue strength of metal components by introducing near-surface plastic strain and residual compressive stress, and can be used for metal surface strengthening. In this study, first shot peening and secondary fine shot peening of hybrid water jet were performed on 18CrNiMo7-6 carburized steel for surface strengthening. Through theoretical analysis of the shot peening residual stress field, a predictive model for the residual stress distribution after shot peening was established and experimentally validated. The results showed that the model maintained good predictions within an acceptable error range. The primary shot peening parameters were based on the comprehensive results of predictive model and experimental validation of the residual stress field from primary shot peening. Primary shot peening trials were conducted with 0.2 mm and 0.5 mm steel wire cut shots, with each shot peening trial conducted twice in forward and reverse directions along the shot peening trajectory to obtain near-saturated residual stress field parameters. Subsequently, based on the good residual stress gradient field results from primary shot peening, secondary fine shot peening was performed on the carburized steel by reducing the shot peening intensity, selecting different shot types, pressures, and other experimental parameters. Surface integrity, including residual stress, surface morphology, and roughness under different processing conditions, was characterized through white light interferometry and X-ray diffraction stress measurement, exploring the relationship between different processing parameters and surface integrity. The results indicated that water jet shot peening could achieve near-saturation state in one pass, with little impact on the overall residual stress field from increasing the number of shot peening passes. Under conditions where the primary shot peening achieved a saturated residual stress field, secondary shot peening using ϕ0.1 mm cast steel shots reduced Ra value from 1.007 μm in FSP to 0.78 μm at the lowest intensity shot peening. With the increasing shot peening intensity, over-peening and stress relaxation occurred, reducing the maximum residual stress depth from 120 μm in FSP to 70 μm, total affected depth from 340 μm to 220 μm, and increasing surface roughness to a maximum of 1.78 μm. The use of ϕ0.05 mm strengthened steel shots and glass shots had no significant impact on the existing residual stress field. With the increasing shot peening intensity, micro-strengthened steel shots initially decreased and then increased the surface roughness, with Ra value reaching a minimum of 0.81 μm at medium-low intensity. Fine glass shots had minimal impact on residual stress field and surface roughness. The best shot peening effect was achieved with cast steel shots at 2 MPa-16 mm/s (pressure, nozzle traverse speed) or micro-strengthened steel shots at 6 MPa-4 mm/s. Therefore, in secondary shot peening processes, using fine shots for medium-low intensity shot peening can significantly improve surface quality after primary shot peening treatment, with slight enhancement in surface residual stress without disrupting the original residual stress field. |
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