The austenite-to-martensite transformation in a partially hardened stainless steel containing 17wt %Cr, 7wt %Ni and 1wt % Al was investigated with Vibrating Sample Magnetometry and Electron Back-Scatter Diffraction. Magnetometry demonstrated that measurable martensite formation can be suppressed on fast cooling to 77K as well as on subsequent fast heating to 373 K. Surprisingly, martensite form...

Friction and abrasive surface treatment of engineering steels is the new effective tool for surface material strengthening and improving the resistance to fatigue damage. The specific abrasive machining of medium-carbon steel yields formation of surface hardened layer with super dispersed nanocrystal structure which increase the fatigue damage resistance in times. The present study aimed to est...

Hard turning, i.e., turning hardened steels, may produce the unique “hook” shaped residual stress (RS) profile characterized by surface compressive RS and subsurface maximum compressive RS. However, the formation mechanism of the unique RS profile is not yet known. In this study, a novel hybrid finite element modeling approach based on thermal-mechanical coupling and internal state variable pla...

Ground penetrating radar (GPR) was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC) hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT) in joint time-frequ...

This study applied laser surface melting process using CW(Continuous wave) Yb:YAG laser and cold-work die steel SM45C and investigated microstructure and hardness. Laser beam speed, power and beam interval are fixed at 70 mm/sec, 2.8 kW and 800 μm respectively. Depth of Hardening layer(Melting zone) was a minimum of 0.8 mm and a maximum of 1.0 mm that exceeds the limit of minimum depth 0.5 mm a...

The interior defect-induced fracture of surface-hardened metallic materials in the long life region has become a key issue on engineering design. In the present study, the axial loading test with fully reversed condition was performed to examine the fatigue property of a surface-carburized low alloy gear steel in the long life region. Results show that this steel represents the duplex S-N (stre...

High hardening of the steel, which is caused by martensitic transformation through cold forming, leads to significant local elastic roll deformation (flattening). The rolling strain-hardened steel requires higher forces and torques, result in high force. Roll flattening can be reduced using rolls made a material with significantly modulus elasticity. suitability ceramic materials for modern hot...