Sinter hardening of PM components
In this column, I will discuss sinter hardening and compare that process to the more traditional heat-treating quench and temper operation.
Introduction
The use of powder...
Determining concentration and required amounts
In this column, I will discuss how to calculate the required amounts of quenchant in a quench tank. This method is also applicable to...
NMTP – Pearlite and ferrite
In this column, we will discuss the non-martensitic transformation products of pearlite and bainite.
Introduction
Pearlite was named by Henry Howe for the pearly phase constituent...
Non-martensitic transformation products: Bainite
In this column, I will discuss the non-martensitic transformation product called bainite.
Introduction
The decomposition of austenite, when occurring at a fast enough rate to exceed...
Residual stresses from machining
In this column, we will discuss the sources of distortion and residual stresses from machining operations. The problem of residual stresses and distortion is...
Pack carburizing of steels
Pack carburizing is a very old method of carburizing steel, but it is still practiced in many tool rooms and machine shops. It is...
Nitriding of steels
In this column, we will discuss the nitriding of steels.
Nitriding introduces nitrogen into the surface of a steel at a lower temperature than carburizing....
Stress relief is a key step in parts manufacturing
In this column, we will discuss the process of stress relief and compare it to the effects of annealing.
During the manufacturing process, residual...
Comparison of carburizing methods
In this column, we will discuss the different methods of carburizing, with a focus on resultant metallurgy.
Introduction
Carburizing is the addition of carbon to the...
Application of cryogenics to improve steel properties
In this column, we will discuss the application of cryogenically treating gears and the outcomes expected.
Introduction
There has been much discussion regarding the application of...
Measuring retained austenite
In this column, we will discuss the different methods of measuring the amount of retained austenite in a heat-treated steel sample.
Retained Austenite
Previously we...
Viscosity and the viscosity index
In this column, we will discuss the viscosity and viscosity index.
Viscosity and the viscosity index are terms that are applied not only to...
A guide to creating a cleaning and washer control plan
In this column, I will discuss the control plan for a generic washer used for cleaning heat-treated parts.
Proper cleaning involves not only removing the...
Control plan for oil-based quenchants
In this column, I will propose a simple control plan for oil-based quenchants and corrective actions.
Oil quenchants have been used extensively to harden steel...
Selecting a cleaner for prewashing prior to heat treatment
In this column, we will discuss the selection of a cleaner for prewashing prior to carburizing. The choice is critical to avoid forming a...
Control plans for polymer quenchants
Polymer quenchants, whether used for immersion quenching or spray applications such as induction hardening, are much more difficult to control than oil quenchants. As...
Quench system design – heating and cooling
In this month’s column, we will discuss the heating and cooling of a quench tank.
All quenching fluids have an optimum operating temperature range requiring...
Different methods of aqueous polymer concentration control
In this article, I will discuss the two different methods for controlling the concentration of polymer quenchants. This is applicable to either induction spray...
Transformation of retained austenite
In this month’s column, I will discuss the transformation of retained austenite, and its stabilization.
In the last column, I reviewed the dimensional changes that...
Dimensional changes during tempering
In this column, I will discuss the dimensional changes that occur during tempering, with a short discussion of the underlying physical metallurgical changes.
Introduction
After quenching,...
