Relation of Compression Residual Stress on Pre-Tensioned Surface in
Parabolic Leaf Spring Submitted to the Stress Shot Peening Process in Carbon
Steel 2023-36-0354
This work deals with the effect of different blasting conditions under stress on
the intensity and distribution of compressive residual stresses. The tests were
performed on bars measuring 17 mm x 70 mm x 1700 mm in AISI 51CrV4 carbon steel.
The samples are considered parabolic leaf spring, as there is a variation in
thickness from the tip to the center, the thickness ay the center is higher than
tip thickness. The samples were laminated to their thickness in double roller
laminators, in order to obtain the desired thicknesses. The samples were
quenched and tempered in industrial scale furnaces. The pre-tensions were
calculated by the ANSYS® software and validated by characterization
with strain gauges, in a test condition of 1400 MPa of pre-tension. Tensile
tests and microstructure analysis were applied to ensure the specification in
terms of strength and microstructure. The stress shot peening process was
performed on a sample with flexural load at two points with a support distance
of 150 mm. The maximum bending pre-tension were 1450 MPa and 1750 MPa. Residual
stresses were measured by X-ray diffraction at five positions. Measurements were
made on samples with deflections and before detonation. Residual stress
measurements on a sample after heat treatment showed tensile residual stress
values. in the deflected samples, the residual compressive stresses increase
from the tip to the center of the specimen, this was demonstrated proportionally
with the validation of the extensometers, but it was not what was presented by
the ANSYS software, establishing differences in the pre-tension of the values of
the surface of the sample.