Effect of induction heating on Vickers and Knoop hardness of 1045 steel heat treated

AISI 1045 steel is a steel of medium carbon, widely used in machinery, the automotive industry, and the food industry, among others. Therefore, to fulfill its purpose, it is necessary to improve its mechanical resistance, wear resistance and resistance to fatigue through different surface heat treatments. Variables such as heating time and hence speed affect the thickness of the hardened layer and the microstructural characteristics of the area affected by heat treatment. The inspection of the transformation of phases during the treatment and the thickness of the boundary layer is generated by determining the hardness of the material, whose procedure is subject to the ASTM E92-17 and E384-17standards, which establish the methodology to be followed. Therefore, the objective of this work is to quantify the effect of three heating times at 1123 K on the hardening of AISI 1045 steel and the regularity of the hardened layer to ensure its functionality as a component subjected to friction, in addition to developing a table of equivalences between the Knoop (HK), Vickers (HK) and Rockwell C (HRC) hardness scales.

Temper Bead Welding, a Possible Solution to Possible Removal of Heat Treatments

The papers aim is to detail temper bead realization, as a possible solution to the removal of heat treatments. Applying temper beads could be a solution for repair, in case surface heat treatments are required, provided they are correctly applied. The paper presents the main ways of applying temper beads, presenting in the same time what the outcomes could be in case of not respecting the prescribed work sequence.

Investigation of the precipitation kinetics and microstructure evolution of martensitic AISI 4140 steel during tempering with high heating rates

During modern surface heat treatments of steels such as laser or induction hardening and tempering, heating rates up to 5000 °C/s or even more can occur in the material. These high heating rates affect the development of the microstructure which in turn affects the material properties. This study presents the results of the investigation of the tempering process of martensitically hardened AISI 4140 at different heating rates up to 1200 K/s. The kinetics of the occurring precipitations were modeled using a modified JMAK equation. The influence on the final microstructure after tempering with different heating rates is investigated using SEM images. The hardness of the different samples was measured in order to show the influence of the heating rate on the mechanical properties. Finally, a comparison to conventional tempering is given.

Nanoparticle-Assisted Heating Utilizing a Low-Cost White Light Source

In this experimental study, a filtered white light is used to induce heating in water-based dispersions of 20 nm diameter gold nanospheres (GNSs)—enabling a low-cost form of plasmonic photothermal heating. The resulting temperature fields were measured using an infrared (IR) camera. The effect of incident radiative flux (ranging from 0.38 to 0.77 W·cm−2) and particle concentration (ranging from 0.25–1.0 × 1013 particles per mL) on the solution's temperature were investigated. The experimental results indicate that surface heat treatments via GNSs can be achieved through complementary tuning of GNS solutions and filtered light.