Development of a Quenching-Partitioning Process Chain for Forging Components (bibtex)

by M. Graf, S. Härtel, A. Bauer, W. Förster, D. Bublikova, M. F.-X. Wagner, B. Awiszus, B. Masek

@Article{graf2018,
  author   = {Graf, M. and Härtel, S. and Bauer, A. and Förster, W. and Bublikova, D. and Wagner, M. F.-X. and Awiszus, B. and Masek, B.},
  title    = {Development of a Quenching-Partitioning Process Chain for Forging Components},
  journal  = {Materials Science Forum},
  year     = {2018},
  volume   = {918},
  pages    = {85 - 92},
  month    = mar,
  issn     = {1662-9752},
  abstract = {The aim is to realize a  {Q\&P} (Quenching and Partitioning) process for a hot forged
component made of low-alloyed advanced high-strength steel (AHSS) 42MnSiCr. One advantage of
this steel is the low alloy concept which is cost-effective. After forging, the component is cooled
down to room temperature with a subsequent heat treatment to achieve the characteristic
microstructure with martensite and retained austenite. The material is annealed and then quenched
to just above the martensite finish temperature (MF-temperature). Hence, in the martensitic matrix
about 10 to 15% retained austenite is included. Finally, the  {Q\&P}ed material is artificially aged at
250 °C to support the diffusion process of carbon from the over-saturated martensite into the
austenite. Thereby, mechanical properties of 2000 MPa for tensile strength with fracture strains of
10% can be achieved. This paper provides details of the process and material behavior for a
reduction of the process chain. The goal is to develop a technology for the quenching and
partitioning treatment of forged components by using the thermal energy from forging. Ideally, the
quenching step should be performed in the forming dies just above the M\textsubscript{F}-temperature with
additional holding on the temperature level. The majority of forged parts have different cross
sections. Therefore, the cooling conditions are inhomogeneous in each cross section of the
components. This cooling behavior was analyzed in laboratory tests with a forged part. Furthermore,
the heat transfer coefficients were determined for different cooling media (water, air). The cooling
technology was experimentally and numerically simulated in a first step for the conventional
process chain (forging, cooling to room temperature, austenitisation, quenching, artificial ageing)
and correlated with the microstructural evolution in combination with the component’s mechanical
properties.},
  doi      = {10.4028/www.scientific.net/MSF.918.85},
}