Heat Treatment of Metals ›› 2023, Vol. 48 ›› Issue (6): 107-113.DOI: 10.13251/j.issn.0254-6051.2023.06.019

• Process Research • Previous Articles     Next Articles

Effect of surface strengthening on microstructure and properties of C17200 beryllium bronze substrate for logging while drilling equipment

Xu Zhigang1, Yang Yang1, Yang Zhongna1, Yao Xiaojiang2, Qin Caihui2, Wang Haipeng1, Liu Liang1   

  1. 1. Failure Analysis Center, CNOOC (Tianjin) Pipeline Engineering Technology Co., Ltd., Tianjin 300452, China;
    2. Zhonghai Oilfield Service Co., Ltd., Langfang Hebei 065201, China
  • Received:2022-11-20 Revised:2023-03-30 Published:2023-08-11

Abstract: According to fatigue failure case of C17200 beryllium bronze logging while drilling (MWD) equipment, the influence of two different surface strengthening processes on microstructure and properties of the C17200 beryllium bronze substrate were investigated, and the failure mechanism was discussed, then the suitable strengthening process was determined. Laser cladding and high-velocity oxygen-fuel (HVOF) were adopted to clad ceramic coating on the adapter. The microstructure and properties of coated and uncoated specimens were compared and analyzed. Optical microscope (OM) and scanning electron microscope (SEM) were used to characterize microstructure of the substrate, and a high-resolution field emission scan electron microscopy (FESEM) and energy dispersive spectrometer (EDS) was used to characterize the grain boundary phase and intragranular phase composition of the over-aged microstructure of the beryllium bronze. The mechanical properties were tested by means of hardness meter and material testing machines. The results show that the heat input of laser cladding has an adverse effect on microstructure and mechanical properties of the beryllium bronze substrate. The local temperature of the substrate reaches 350 ℃, the microstructure is over-aged, and the increase of grain boundary reaction brings a large number of γCu88be12 nodules which results in the strength decreases and the lowest hardness of the substrate is only 12 HRC. However, the HVOF has little effect on microstructure and properties of the substrate, and the microstructure and properties are normal without aged structure. It is concluded that the HVOF sprayed ceramic coating can improve the reliability and safety of the adapters, which is suitable for the surface reinforcement of C17200 beryllium bronze for MWD equipment.

Key words: C17200 beryllium bronze, fatigue fracture, microstructure and properties, high-velocity oxygen-fuel (HVOF), laser cladding, over aging

CLC Number: