Monday, November 28, 2022

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...

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...

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...

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...

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....

Case Depth Determination

Methodology to ensure design intent is satisfied

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...

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...

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...

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....

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,...

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...

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...

Carbon potential verification

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

Pyrometry, Industry Standards, & Temperature Uniformity Surveys

In its simplest sense, pyrometry is the measurement of temperatures. Practically speaking, in the business of heat treatment, the term also refers to the...

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...

Gas Nitriding

In general, nitriding of parts involves a thermal process that provides a tough, corrosion-resistant, and wear-resistant surface with less distortion compared to other case...

Compelling reasons normalizing produces high quality gears

In this day and age, adding steps to the gear manufacturing process is not highly desirable unless the benefits far outweigh the costs incurred....

Variation in 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...

Residual stress evaluation in bearings

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

Predicting hardness by the Grossman H-Value

In the last article, we described a method of calculating the Grossman H-Value . In the article before last, we described a method of...

Heat-treatment of modified 9CrMo steel

The modified 9CrMo steels, such as Grade 91, Grade 92, and HT9, are materials of choice for fossil-fuel-fired power plants and Next Generation Nuclear...
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