Effect of Microshot Peening on Fatigue Strength of Austenite Stainless Steel

2021 ◽  
Vol 1016 ◽  
pp. 145-150
Author(s):  
Yasunori Harada ◽  
Katsuhiko Takahashi
Keyword(s):  
Stainless Steel ◽  
Fatigue Strength ◽  
Cast Steel ◽  
Surface Characteristics ◽  
Average Diameter ◽  
Hardened Layer ◽  
Material Surface ◽  
Workpiece Surface ◽  
The Media ◽  
Type Machine

The effects of the peening conditions on the surface characteristics and fatigue strength of stainless steel were investigated by microshot peening (MSP). In recent years, MSP technology has attracted attention. The use of MSP technology with minute media has become more widespread in consideration of the reduction of the notch effect in the material surface. However, the effect of MSP technology on stainless steel has not been much studied. In the present study, an air-type machine was used. The media used was high-carbon cast steel (490 HV) and Fe-Cr-B alloy (1130 HV), with an average diameter of 0.1 mm. The peening time was in the range of 0 - 100 s. Four types of stainless steels, SUS304, SUS304L, SUS316, and SUS316L, were tested. The workpieces were annealed at 1100 K for 1.2 ks in air. In the measurement of fatigue strength, the workpieces were machined in hour-glass shape. As the results, surface roughness of the workpieces treated by MSP was small. Work hardening was evident to the depth of approximately 0.2 mm from the surface. This depth was about twice the diameter of shot media. However, the effect of the peening time on the hardness distribution was not large. The compressive residual stress was added in the surface vicinity. It is assumed that the fatigue limit had increased because the work hardened layer was formed near the workpiece surface.

Effect of Different Shot Peening Treatments on Fatigue Life in Ti Alloy

2018 ◽  
Vol 941 ◽  
pp. 908-913
Author(s):  
Yasunori Harada ◽  
Yuto Saeki ◽  
Katsuhiko Takahashi
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Shot Peening ◽  
Work Hardening ◽  
Cast Steel ◽  
Average Diameter ◽  
Hardened Layer ◽  
Material Surface ◽  
Ultrasonic Shot Peening ◽  
The Media

The effects of peening conditions on the surface characteristics and fatigue life of titanium alloy was investigated using microshot peening, ultrasonic shot peening, and multiple shot peening. The use of microshot peening technology with minute media has become more widespread in consideration of the reduction of the notch effect in the material surface. The ultrasonic shot peening that uses media of several millimeters in size with ultrasonic vibration has attracted attention as a means to reduce the surface roughness. In the present study, an air-type and an ultrasonic type machine were used. In the microshot peening process, the media used was high-carbon cast steel and the hard powder, with an average diameter of 0.1 mm. The workpiece was commercial titanium alloy Ti-6Al-4V. In the microshot peening (MSP), work hardening was evident to the depth of approximately 0.3 mm from the surface. This depth was approximately three times the diameter of the media. However, the influence of the peening time on the hardness distribution was not great. In the ultrasonic shot peening (USP), work hardening was deeper in the material. This is because the diameter of the media used for ultrasonic machining was large. On the other hand, in the combined shot peening (CSP), a degree of hardness was higher at the top surface. However, the hardness patterns and values were pretty much identical to ultrasonic shot peening. The fatigue limit was thought to be greater in the microshot peening experiment because the work-hardened layer was formed near the workpiece surface.

Surface Modification of Magnesium Alloy by Shot Lining and Laser Heating

2016 ◽  
Vol 879 ◽  
pp. 703-708
Author(s):  
Yasunori Harada ◽  
Minoru Matsumoto ◽  
Masayuki Nunobiki ◽  
Katsuhiko Takahashi
Keyword(s):  
Magnesium Alloy ◽  
Shot Peening ◽  
Cast Steel ◽  
Hardness Test ◽  
Aluminum Foil ◽  
Surface Characteristics ◽  
Heat Treated ◽  
Wide Range ◽  
Type Machine ◽  
High And Low Temperatures

Magnesium alloy has a wide range of application prospects in the automobile and electronic industries. However, peeling of the coating material may occur under harsh environments such as high and low temperatures and high humidity with the conventional coating techniques. The authors have proposed a lining process of metals with thin aluminium foils using shot peening. In this method, the foil can be bonded to the workpiece surface bringing about large plastic deformation. The pressure generated by the hit of many shots is utilized for the bonding. In the present study, to improve the surface characteristics of magnesium alloy, the formation of an Fe-Al intermetallic compound film on magnesium alloy by compound treatment combining shot lining method and heat treatment was mainly investigated. Shot peening was performed with a centrifugal-type machine using cast steel ball. The lined sheet is aluminum foil with pure iron powders, and the workpiece was the commercial magnesium alloys. The lined workpieces are heat treated by laser in air. The Vickers hardness test was performed with a microhardness tester. It was confirmed that the present method could be used for the formation of functional films on the magnesium alloy.

Effect of Heating and Subsequent Re-Shot Peening on Surface Characteristics of Shot-Peened Carbon Steel

2011 ◽  
Vol 325 ◽  
pp. 739-744 ◽  
Author(s):  
Yasunori Harada
Keyword(s):  
Carbon Steel ◽  
Shot Peening ◽  
Cast Steel ◽  
Surface Hardness ◽  
Surface Characteristics ◽  
Heat Treated ◽  
Processing History ◽  
History Of ◽  
Type Machine ◽  
Steel Balls

The shot peening process is one of the surface treatments. In this process the peening effects are characterized by the fact that the surface layer undergoes large plastic deformation due to the collision of shots. The effects are greatly influenced by the processing history or the thermal history of material. Little is known about the relation between hardness of the shot peened surface and the processing history of materials. In the present study, the effect of heating and subsequent re-shot peening on the surface characteristics of the shot-peened carbon steel was investigated. Shot peening was performed with an air-type machine using cast steel balls. Hardness and compressive residual stress in the re-shot peened workpieces were measured. When the heat treated workpiece was re-processed by shot peening, surface hardness and fatigue life of carbon steel were improved. It was found that the surface characteristics of the peened carbon steel were improved by heating and subsequent re-shot peening.

scholarly journals Post-Processing and Surface Characterization of Additively Manufactured Stainless Steel 316L Lattice: Implications for BioMedical Use

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1376
Author(s):  
Alex Quok An Teo ◽  
Lina Yan ◽  
Akshay Chaudhari ◽  
Gavin Kane O’Neill
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Characterization ◽  
High Surface ◽  
Surface Characteristics ◽  
Post Processing ◽  
Stainless Steel 316L ◽  
Processing Methods ◽  
Particulate Debris

Additive manufacturing of stainless steel is becoming increasingly accessible, allowing for the customisation of structure and surface characteristics; there is little guidance for the post-processing of these metals. We carried out this study to ascertain the effects of various combinations of post-processing methods on the surface of an additively manufactured stainless steel 316L lattice. We also characterized the nature of residual surface particles found after these processes via energy-dispersive X-ray spectroscopy. Finally, we measured the surface roughness of the post-processing lattices via digital microscopy. The native lattices had a predictably high surface roughness from partially molten particles. Sandblasting effectively removed this but damaged the surface, introducing a peel-off layer, as well as leaving surface residue from the glass beads used. The addition of either abrasive polishing or electropolishing removed the peel-off layer but introduced other surface deficiencies making it more susceptible to corrosion. Finally, when electropolishing was performed after the above processes, there was a significant reduction in residual surface particles. The constitution of the particulate debris as well as the lattice surface roughness following each post-processing method varied, with potential implications for clinical use. The work provides a good base for future development of post-processing methods for additively manufactured stainless steel.

scholarly journals Titanium oral implants: surface characteristics, interface biology and clinical outcome

2010 ◽  
Vol 7 (suppl_5) ◽  
Author(s):  
Anders Palmquist ◽  
Omar M. Omar ◽  
Marco Esposito ◽  
Jukka Lausmaa ◽  
Peter Thomsen
Keyword(s):  
Surface Properties ◽  
Cellular Response ◽  
Randomized Clinical Trials ◽  
Three Dimensional ◽  
Cell Communication ◽  
Surface Characteristics ◽  
Titanium Implants ◽  
Material Surface ◽  
Oral Implants

Bone-anchored titanium implants have revolutionized oral healthcare. Surface properties of oral titanium implants play decisive roles for molecular interactions, cellular response and bone regeneration. Nevertheless, the role of specific surface properties, such as chemical and phase composition and nanoscale features, for the biological in vivo performance remains to be established. Partly, this is due to limited transfer of state-of-the-art preparation techniques to complex three-dimensional geometries, analytical tools and access to minute, intact interfacial layers. As judged by the available results of a few randomized clinical trials, there is no evidence that any particular type of oral implant has superior long-term success. Important insights into the recruitment of mesenchymal stem cells, cell–cell communication at the interface and high-resolution imaging of the interface between the surface oxide and the biological host are prerequisites for the understanding of the mechanisms of osseointegration. Strategies for development of the next generation of material surface modifications for compromised tissue are likely to include time and functionally programmed properties, pharmacological modulation and incorporation of cellular components.

Spot Weldability Assessment of Similar and Dissimilar Steel Sheets for Light Weight Automobile Body

2006 ◽  
Vol 306-308 ◽  
pp. 899-904
Author(s):  
Dong Ho Bae ◽  
Won Seok Jung ◽  
J.B. Heo
Keyword(s):  
Stainless Steel ◽  
Fatigue Strength ◽  
Lap Joints ◽  
Vehicle Body ◽  
Rolled Steel ◽  
Cold Rolled Steel ◽  
Steel Sheets ◽  
Automobile Body ◽  
Cold Rolled ◽  
Spot Welded

An effective way to reduce the weight of vehicle body seems to be application of new materials, and such trend is remarkable. Among the various materials for automobile body, stainless steel sheets and cold rolled steel sheets are under the interests. However, in order to guarantee reliability of new material and to establish the long life fatigue design criteria for body structure, it is necessary to assess spot weldability and fatigue strength of spot welded lap joints fabricated under optimized spot welding condition. In this paper, spot weldability of stainless steel sheets, STS301L and STS304L, and cold rolled steel sheets, SPCC and SPCD. Fatigue strength of lap joints spot welded between similar and dissimilar materials were also assessed.

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