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...
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...
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...
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...
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...
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...
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...
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,...
Carbon potential verification
Choose from several verification methods for best fit, then develop a plan to correct for out-of-spec test results
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...
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...
Residual stress evaluation in bearings
Lingering stress is not easily identified during production, but has a direct impact on wear performance and fatigue life
Distortion during heating
Minimizing distortion involves more than just optimizing cooling
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...
Carburizing Optimization & ECD Precise Control
As discussed in the September/October 2016 Metal Urgency column , carburizing is a nonsteady-state diffusion process and thus can be expressed by Fick’s second...
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...
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...
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...
Linear-elastic fracture toughness testing
Materials fracture occurs in all sectors of the economy — aerospace, nuclear, medical, transportation, oil and gas, petrochemical, commercial and residential buildings, etc. The...
Creep deformation mechanisms in 9CrMo steel
The Generation-IV reactors in nuclear power plants are expected to address the growing energy demand by producing electricity and, at the same time, mitigating...
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...
Achieving results through cold treatment
Cold treatment is a sub-zero thermal treatment process primarily used to reduce the retained austenite content of alloy and high carbon steels. Cold treatment...
Surface stress is key in rolling contact fatigue
Most bearing failures can be attributed to some form of rolling contact fatigue. Many factors influence rolling contact fatigue, but two main factors are...
Induction Hardening Choices for Gears
Of the various types of applied energy processing, induction hardening is the most common. Induction heating is a process that uses an alternating electrical...
An overview of heat treatment techniques
Editor’s note » This is the second in a five-part series.
In this second segment of my series on heat-treating techniques, I will discuss the...
Hardening and tempering in the same cell
Tempering hardened steels is one of the most important heat treating processes used in part manufacturing. Induction tempering produces hardness and mechanical properties similar...
Kanthal APMT for nuclear-energy application
The major earthquake and tsunami that occurred in Japan in 2011 did serious damage to boiling water reactors of the Fukushima-Daiichi nuclear power plant....
Heat treatment techniques overview
Editor’s note » This is the third in a five-part series.
In this third segment of my series on heat-treating techniques, I will discuss the pros and...
Evaluating a material’s response during austenitization
Carbon content in steel has a direct correlation to the hardness and overall strength of a component after heat treatment. Carbon can take many...
Enhanced properties of metal matrix nanocomposites
Application of carbon nanotube (CNT) reinforced metal matrix nanocomposite (MMNC) has been increasing rapidly since the discovery of CNT in the 1990s. These novel...
Simulation tools to effectively calculate process
One common goal for a wide range of industries has been to increase power density in shaft and gear components. The steel producing industry...
Inducing heat treatment for case hardening
Induction hardening has become an increasingly popular heat-treatment method for steel due to its extremely fast processing speeds. Compared to other case hardening methods,...
Using welding simulation tools to model WAAM
In its simplest form, additive manufacturing has been used since before the common era where low temperature melting materials such as tin, silver, copper,...
Testing of Induction Hardened Work Pieces
Hardness testing is a simple and universally accepted practice for checking induction hardened parts and is performed in literally thousands of manufacturing facilities. There...
Improving temperature uniformity during tempering
The final step in any steel heat-treatment quenching process which produces a martensitic microstructure is tempering. Martensite is a metastable phase and is extremely...
Modeling can improve press quenching process
A combination of carburization and quench hardening is often used to increase the strength and improve fatigue performance of steel parts. During quenching, stresses...
Stress evolution during quench hardening of steel
Quench hardening of steel components involves complex, nonintuitive phenomena, particularly as it relates to the dimensional changes and stresses induced. Figure 1 shows a...
Combatting undesirable NMTP formations
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,...
