Understanding the Jominy end quench test

The Jominy end quench test (ASTM A255 ) is an extremely simple and useful test that is applicable to many materials besides steel...

Use of molten salt in heat treatment

At the turn of the 20th century, the use of molten salt as a heating and quenching medium for steels was developed in England....

An overview of refractory ceramic fibers

This article will review refractory ceramic fibers (RCFs), which are amorphous, inorganic, man-made aluminosilicate fibers. RCFs belong to a class of materials termed man-made...

Carbon Diffusion and Carburizing Parameter Selection

Although carburizing is a complicated process, it can be broken down into two main steps: carbon generation in the furnace and carbon diffusion into...

Heat treatment of aluminum VI – Artificial aging

In the previous column, we described the fundamentals of natural aging. In natural aging, the solid solution obtained after quenching starts to form precipitates...

Case Depth Determination

Methodology to ensure design intent is satisfied

A technical guide to quenching

From a quality perspective, verification of the conformance of quench requirements can be accomplished by examining a furnace chart that shows the quench trend....

Carburizing

While some heat treatments are used to soften the material or improve its machinability, most are processed to obtain strengthened or hardened properties. The...

Determining austenite grain size

Grain size is a critical metallurgical characteristic, significantly influencing design parameters such as strength and toughness. Austenite grain size (often referred to as prior-austenite...

Heat treatment of aluminum – Part II

In my article last month, I discussed the alloying elements used in aluminum alloys. In this article, I will be discussing the solution heat...

Using water as a quenchant

In this short column, we will discuss quenching with water. As a quenching medium, plain water approaches the maximum cooling rate attainable in a...

An overview of insulating firebricks

Ceramic refractory materials are useful for the following functions: 1. Serving as a thermal barrier between a hot medium and the wall of a...

Hardening depth measurement

Surface hardening heat treatments are popular in the manufacture of steel products as a means of significantly improving strength and fatigue resistance and mitigating...

Retained austenite significant for strength, toughness

The role of retained austenite (RA) and the magnitude of its influence on the performance of steel components are continually debated. Depending on the...

Heat treatment of aluminum, part II: Water quenching

In the last article, we talked about the metallurgy behind quenching aluminum. Now we are going to discuss the available quenchants for aluminum. Introduction To achieve...

Heat treatment of aluminum – Part I: Quenching basics

In previous articles, we discussed the role of alloying elements and discussed the solution heat treatment of aluminum. We showed that it is important...

Performing a Temperature Uniformity Survey

Performing a temperature uniformity survey (TUS) can be somewhat of a daunting process. After all, a TUS carries the weight of not only being...

Understanding the effect of boron in steels

In this column, we will discuss the effect of boron additions to steel and its influence on properties. Boron, B, is an element with an...

Non-Martensitic Transformation Products (NMTP)

Whether formed during a conventional quench and tempering process, carburizing, or induction hardening, non-martensitic transformation products (NMTP) are widely considered undesirable microstructural features. However,...

How to keep decarburization in check

The performance of heat-treated steel components is largely dependent on the condition of their surface. Wear and fatigue resistance are examples of design criteria...

Carbon potential verification

Choose from several verification methods for best fit, then develop a plan to correct for out-of-spec test results

Materials Selection for Induction Hardening Processes

Induction hardening is the most common technique of the various types of applied energy processing. It uses alternating current that induces a magnetic field...

Microstructural evolution, its effect on Ti6Al4V alloy

Titanium alloys are extensively used in aerospace, petrochemical, marine, and medical applications, thanks to their superior strength-to-weight ratio at elevated temperature, corrosion resistance, and...

Heat treatment of aluminum, Part V

After quenching and any straightening, the supersaturated solid solution of aluminum wants to reach equilibrium. It does this through the process of precipitation hardening....

ASTM E18 and Nadcap: Rockwell hardness testing

Rockwell hardness testing is a common way to ensure the material response to heat treat is conforming and is required by applicable industry and...

Hardness scale conversion

The use of hardness testing as a quality control method to check the outcome of a thermal treatment process is a common application of...

Residual stress evaluation in bearings

Lingering stress is not easily identified during production, but has a direct impact on wear performance and fatigue life

Troubleshooting induction hardening problems: Part 1

Induction hardening is a unique method used to harden steels. The process uses a power supply, RF generator, induction coil, and quenching mechanism (spray...

AMS2750F contains key pyrometric changes

By now, most heat treaters should have had some time to read the new revision of AMS2750. The changes are extensive and, since it...

Carbon: Essential element or too much of a good thing

52100: Simple, yet it embraces carbon’s two-way benefit to steel

The heat treatment of aluminum – Introduction

Aluminum’s many desirable properties, such as high strength-to-weight ratio, good corrosion resistance, ease of processing, and low cost, make it a very widely used...

Heat treatment of aluminum Part VII – Hardness and conductivity

In the previous article, we discussed the artificial aging of aluminum. Once we have heat treated the parts, we need to verify the properties....

Furnace Doors

No matter the configuration, single or multi-chamber vacuum, batch integral quench, continuous, or even pits — an item that all furnaces have in common...

Determining Grossman H-value from cooling curve data

In the last article, I described how the Jominy end quench test could be used to predict hardness for a series of different round...

Heat treating is not for the faint of heart

Why heat-treating furnaces look the way they do, Part 2

Classifying non-metallic inclusions in steels

In this column, we will discuss the different types of inclusions present in steels and discuss their physical metallurgy. As property requirements increase, and...

Different Scales Are Used For Rockwell Hardness Testing

Production Bench Rockwell Hardness Testing of Small Work Pieces As induction hardened workpieces get smaller in size, attention to the proper abrasive cutting of the...

Determining Austenite Grain Size

Grain size is a critical metallurgical characteristic, significantly influencing design parameters such as strength and toughness. Austenite grain size (often referenced to as prior-austenite...

Variation in steel hardenability

Many heat-treating processes cannot tolerate appreciable variations in steel hardenability. For an established in-control process, deviations in chemical composition and starting microstructure may result...

Process quality control in heat treatment

In thermal processing, process quality control is imperative to produce and control conforming product and overall conformance. In this article we will be examining...