Articles By D. Scott MacKenzie, Ph.D., FASM


Hot Seat: Oil Quenchants – Understanding the Chemistry (Part III)

In this issue, a discussion of the mechanism of quench oil, focusing on oxidation, thermal degradation, contamination, and additive depletion.

Hot Seat: Metallurgical Reasons for Grinding Cracks and Their Detection

Aggressive grinding can result in thermal damage and potential cracking of a ground part, but methods exist to detect grinding burns and cracks.

Hot Seat: Hardenability

Factors that affect hardenability and the rate of austenite transformation — carbon content, grain size, and alloying elements — can be used to calculate hardenability for comparing alloy grades.

Hot Seat: Applications of Hardenability

A method is described to either calculate the hardness in a component given the quenchant used or to select a quenchant to achieve a desired hardness at the core or surface of a part.

Hot Seat: Development of Residual Stresses During Machining and Workholding

Machining and fixturing prior to heat treatment are among the many potential sources for distortion and residual stress.

Hot Seat: Surface Engineering of Steels

Surface engineering draws upon chemistry, material science, metallurgy, tribology, and biology to enhance surface properties for improving parts.

Hot Seat: Heat Treatment of AISI 52100 For Bearing Applications

Manufacturing a component is oftentimes extremely complex, even when that component seems as simple as a bearing.

Hot Seat: Surface Engineering of Steels: Understanding Carburizing

Carburizing is a widely used, effective technique to increase surface hardness of steel used in gears, and achieve a compressive residual stress. There are several methods, and hotter isn’t always better.

Hot Seat: How Parts Cleaning Maximizes Heat Treatment

The impact of proper cleaning and rinsing on part quality prior to heat-treating is critical to the surface finish and overall quality of the finished gear.

Hot Seat: The Effects of Microstructure and Hardenability on Distortion

In order to truly understand the distortion that can occur during heat treatment, it’s important to understand the issues of prior microstructure and hardenability.

Hot Seat: Contamination of polymer quenchants in induction hardening

Some think coolants or other contamination do not harm the quenchant. This perception couldn’t be farther from the truth.

Hot Seat: Oil Quenchants Understanding the Chemistry (Part I)

This installment explores the chemistry of oil quenchants and the effects of additive packages on quenching performance, to be followed in February by a discussion of base oils.

Hot Seat: Oil Quenchants – Understanding the Chemistry (Part II)

This installment explores the chemistry of base oils, particularly as they affect quenching performance, to be followed in March by a discussion of quench oil oxidation.

Hot Seat: Corrective actions for degraded quench oil

Quench oil oxidation is a serious problem, but it can be overcome with appropriate corrective actions listed here.