Friday, October 4, 2024

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....

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...

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...

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...

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...

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...

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....

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...

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....

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...

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...

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...

The mechanism of creep and its stages

In this column, I will discuss the mechanism of creep and its three stages. Applications of metals at elevated temperatures involve several problems. It is...

Heat treating is not for the faint of heart

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

Heat treatment of aluminum, quenching Part III

In the last article, we discussed quenching of aluminum, and the importance of rapid quenching to prevent the formation of precipitates at the grain...

Stainless Steels

Kitchen sinks, refrigerator or oven doors, and tableware are what many people think of when they are asked what’s made from stainless steel (SS)....

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 aluminum IV: Handling distortion

After quenching, depending on the quenchant used, distortion of parts can occur. This is particularly true for water-quenched parts. Parts must be straightened. This...

Safety considerations when quenching with oil or salt

In this column, we will consider safety aspects of quenching with oil or molten salt. Heat treating is a manufacturing process where the goal is...

Estimating required flow through quench tanks

In this month’s column, I will discuss a method of estimating the required flow for a quench tank. Agitation has a significant effect on...

Understanding the basics of spray quenching

Spray quenching involves the removal of heat by the impingement of a liquid quenchant on a hot metal surface. Examples include: Fog quenching. Quenching...

Hardenability – the influence of tramp elements

Hardenability is the property of a material to deeply harden, and not the ability to get hard . This basic concept has driven much...

Furnace Types

Heat treating furnaces consist of several subassemblies: insulation (fiber and brick), heating systems (electric and gas), material handling, quenching, atmosphere system, process and control...

Thermal triplets: PM, sintering, and case hardening

From my experience, powder metals (PM), sintering, and case hardening are three processes that could be said to be joined at the hip. More...

Control of distortion in heat-treated aluminum

In this column, we will discuss controlling the distortion of aluminum heat-treated components. The heat treatment of aluminum (solution heat treatment, quenching and aging) are...

Troubleshooting induction hardening problems: Part 2

Last month, I began a two-part article about troubleshooting induction hardening problems and discussed possible corrections. This month, I will discuss biological and odor...

Anatomy of a Heat-Treating System

Ninety-eight 600-pound trays are in continuous process, 13 are in the pre-process queue, nine preheating, 14 in the boost carb, eight in the diffusion...

Use of molten salts for martempering of steel

In July’s column, I talked about molten salts and the different types. In this short column, we discuss the benefits of using molten salts...

Blistering of aluminum during heat treatment

In this column, we will discuss the blistering of aluminum during heat treatment, and methods to prevent its occurrence. Introduction High-temperature oxidation, or blistering, often occurs...

Developing a superalloy with superior heat resistance

Demand for superior machinery that can operate effectively under extreme conditions is driving the development of newer alloys. One significant example is the preparation...

Intensive Quenching

Heat treating is similar to art in many ways, but not for the reasons you might think. Art, it’s said, is in the eye...

Heating with natural gas

It’s no secret that the heat treating industry is one of the major recipients of the impact when the U.S. Environmental Protection Agency (EPA)...

Furnace Maintenance

When a heat treat manager or anyone responsible for purchasing heat treating equipment makes a buy decision, they must first consider the process required,...

Cooling rate after tempering

In this column, I will discuss the effect of cooling rate after tempering. Introduction During heat treatment of steel, the process is generally austenitize, quench, and...

Troubleshooting induction hardening problems – Part III

In previous columns, I have provided some detail on the sources of problems with induction hardening.  While I have tried to be inclusive, there...

Heat Treating, Furnaces, and Unintended Consequences

A few decades ago, my involvement with depleted uranium (DU) began in the metallurgical R&D department, developing program logic to heat treat DU in...