Back to basics: Martempering to reduce distortion
In the previous article, we discussed the principle of quench and temper, which is arguably the most common type of steel heat-treating. In this...
Back to basics: Quenching, tempering as heat treatments
This article describes the most common type of heat treatment of steel. This includes austenitizing, quenching, and tempering. In this process, the part is...
Getting back to basics with tempering
Once a part has been quenched, it must be tempered. This accomplishes two things: First, it relieves the thermal and transformational stresses from quenching....
Understanding the different types of heat treating
In the last article, we discussed many different types of annealing, and the reduction of distortion by application of stress relief annealing. In this...
Understanding different types of heat treatment: Annealing
In the last few installments we discussed the use of Time-Temperature-Transformation and Continuous Cooling Transformation diagrams to understand the phase changes that occur during...
Continuous Cooling Transformation Diagrams
In the last column, we discussed the construction and application of Time Temperature Transformation or Isothermal Transformation diagrams. It was shown how these diagrams...
The Time-Temperature-Transformation Curve
In the previous column, we discussed the formation of the Iron-Carbon phase diagram. This diagram allowed us to estimate the microstructure under non-equilibrium conditions....
Back to basics on heat-treatment of steel, underlying metallurgy
In this article, and future articles, we will discuss the basics of the heat-treatment of steel and the metallurgical reason behind it. We start...
Heat treatment of powder metallurgy parts
The use of powder metallurgy (P/M) for the production of near-net shaped parts has increased in recent years due to performance gains, as well...
Safe operation of endothermic atmospheres
In the last column, we discussed the importance of making sure that the endothermic atmosphere was the right composition to ensure proper heat treatment....
Endothermic atmospheres used for heat treating
During heat treatment, the part experiences different temperature regimes (Figure 1). Atmospheres are used in heat treating to protect the part from scaling at...
Water in oil-based quenchants can be problematic
The continuing retirement of “old hands” in the heat treatment industry has a growing generation of operators, supervisors, and engineers not knowing the severe...
Corrective actions for degraded quench oil
In the past several columns, the various components of a quench oil have been described. Illustrations on how the various components, such as the...
Oil Quenchants – Understanding the Chemistry (Part III)
In the last two installments, the effects of base oil and additives on the performance of quench oil were described. In Part III, the...
Oil Quenchants – Understanding the Chemistry (Part II)
In this installment we will focus on base oils. Engineered quench oil is governed by the desired quenching performance; the necessary thermal and oxidative...
Oil Quenchants: Understanding the Chemistry (Part I)
Oil quenchants have been used extensively to harden steel in excess of 100 years. There are a wide variety of commercially available quenchants on...
Contamination of polymer quenchants in induction hardening
Induction hardening is a common and effective method of achieving a hard, wear-resistant surface without carburizing or nitriding. It is used extensively to harden...
The Effects of Microstructure and Hardenability on Distortion
Distortion is a worldwide problem in heat-treating, and has ramifications in part quality, additional manufacturing costs, and part performance. The cost implications are immense....
How Parts Cleaning Maximizes Heat Treatment
The demands of heat-treated goods are increasing. Not only do they have to meet property and straightness requirements, but they also have to meet...
Surface Engineering of Steels: Understanding Carburizing
Carburizing is the addition of carbon to the surface of low carbon steels. It is generally accomplished at temperatures between 850-1,000°C. Once quenched, the...
