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Journal Article

Distortion and Residual Stresses in Nitrocarburized and Carbonitrided SAE 1010 Plain Carbon Steel

2008-04-14
2008-01-1421
The focus of this study was to determine the residual stress and retained austenite profiles for carbonitrided and nitrocarburized SAE 1010 plain carbon steel and to relate these profiles to one another and to the distortion resulting from heat treatment. Navy C-ring specimens were used for the purpose of this study and X-ray diffraction techniques were used to measure both residual stress and retained austenite. The findings from this research are then applied to a manufacturing application involving the surface hardening of a thin shelled, plain carbon steel automotive component.
Journal Article

Microstructural Effects on Residual Stress, Retained Austenite, and Case Depth of Carburized Automotive Steels

2008-04-14
2008-01-1422
SAE 8620 and other steels are typically used in the carburized condition for powertrain applications in the automotive industry, i.e., differential ring gears, camshafts, and transmission gears. Although current recommended carburizing practice involves normalizing the steel prior to carburizing, elimination of this normalizing treatment could lead to significant cost reductions. This research examines whether the normalizing process prior to carburizing could be eliminated without negatively affecting part performance. This study focused on the effects of the initial microstructure on the residual stress, retained austenite, and effective case depths of carburized SAE 8620 and PS-18 steels.
Technical Paper

The Use of Navy C-Ring Specimens to Investigate the Effects of Initial Microstructure and Heat Treatment on the Residual Stress, Retained Austenite, and Distortion of Carburized Automotive Steels

2007-04-16
2007-01-0806
Steels such as SAE 8620 and PS-18 are typically used in the carburized condition for powertrain applications in the automotive industry. Such steels always contain retained austenite to varying degrees in both the ashardened and tempered microstructures. As well as retained austenite, heat treatment can produce residual stresses, which lead to both size and shape distortions. The intent of this study was to investigate the effects of initial microstructure, composition, and heat treatment on the amount of residual stress, retained austenite, and distortion in carburized SAE 8620 and PS-18 steels. A specially designed specimen, the Navy C-ring, was used to evaluate distortion. X-ray diffraction techniques were used to determine the residual stress and the amount of retained austenite.
Technical Paper

Improving Fillet Weld Fatigue Performance by Improving Weld Shape

1998-04-08
981509
The fatigue performance of fillet-welded transverse attachments was compared for several procedure variants for both FCAW and SAW on ½ in. steel plates. Measurements of weld toe shape on adjacent pieces of weld indicated that smoother weld toes, as evidenced by larger weld toe radius, were correlated to improved fatigue performance for both processes. Fatigue tests conducted on 59 and 109 ksi yield strength plates did not show an effect of plate strength. Weld procedures designed to provide smooth toes, such as reduced parameter FCAW beads at horizontal weld toes and flat position FCAW at higher heat inputs, were shown to provide fatigue performances near post-weld improved fillets.
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