EFFECTS OF Q&P PROCESS PARAMETERS ON PROPERTIES OF 42SiCr STEEL

Abstract

<p class="AMSmaintext"><span lang="EN-GB">The requirement for high strength and good ductility poses problems in today’s advanced steels. This problem can be tackled by appropriate heat treatment which produces suitable microstructures. By this means, ultimate strengths of about 2000 MPa and elongations of more than 10% can be obtained. One of such advanced heat treatment techniques is the Q&P (Quenching and Partitioning) process. It produces a mixture of martensite and retained austenite, where the latter is an important agent in raising the ductility of steel. </span></p><p class="AMSmaintext"><span lang="EN-GB">In this experiment, a low-alloy steel with 0.41% carbon and manganese, silicon and chromium was used. An air furnace and a salt bath were employed for heat treatment and quenching, respectively. In order to obtain the best ultimate strength and elongation levels, partitioning temperatures of 250°C and 300°C were applied. Partitioning involves carbon diffusion from super-saturated martensite into retained austenite, and tempering of hardening microstructure. Effects of the quenching temperatures of 200°C and 150°C were studied as well. To map the impact of the Q&P process on mechanical properties, an additional schedule with conventional quenching and tempering was carried out. Upon optimization of the parameters, the process produced martensite with a small amount of bainite and retained austenite. The ultimate strength was between 1930 and 2080 MPa and the elongation levels were from 9 to 16%.</span></p><p class="AMSmaintext"><span lang="EN-GB"> </span></p>

Effect of Sensitization Treatment on Corrosion Properties in Austenitic Stainless Steel 304

“…The ratio of current density increased as a function of annealing time. The degree of sensitization is influenced by factors such as the steel chemical composition, grain size, degree of stain or temperature and time of annealing [9].The sensitization involves both nucleation and growth of intermetallic phases (Cr 23 C 6 ) at the grain boundaries. The results of the optical microscopy and electron microscopy images are summarized in Fig.…”

Element partitioning in low-carbon Si2Mn2CrMoVNb TRIP-assisted steel in intercritical temperature range

“…TRIP-effect results in enhancement of steel strength/ductility combination [13,14] as well as in improvement in exploitation behaviour such as abrasive/erosive wear resistance [15][16][17]. A carbon partitioning between the phase constituents is a common feature of heat processing of different steel grades (TRIP-assisted steels [1,5], QP-steels [18,19], nanobainite steels [20]). During the intercritical annealing, carbon partitions between ferrite and austenite in order to reach a thermodynamic equilibrium being driven by the big difference in carbon equilibrium solubility in -Fe and -Fe.…”

Comparing Properties of the 42SiCr Steel After Conventional Heat Treatment and QP Processing

“…Rubešová et. al [8] carried out a research focused on the effect of the quenching and partitioning temperatures on the 42SiCr steel treated by QP process. Various modes of heat treatment was designed from which the quenching in the 150 °C molten salt and subsequent partitioning at 250 °C for 10 minutes was assessed as the best one.…”

“…The differences in the elongation and RA content were observed. The QP process parameters were designed according to the above mentioned research [8] i.e. quenching in the 150 °C molten salt and partitioning at 250 °C for 10 minutes.…”