Posted on March 31, 2018
Sometimes the physical properties of hardness and hardenability are confused. Hardness represents an existing condition after processing by heat treatment. It is a direct indicator of the mechanical strength of the steel. Hardenability denotes the potential of a steel to develop a particular value of hardness after a particular heat treatment. Hardenability is primarily dependent […]
Posted on November 12, 2015
A common cause of failures in various types of equipment is fatigue failure of bolts that secure parts together. Fatigue in any type of dynamically loaded mechanical component accounts for more than 80% of all failures. This post reviews some important factors in fatigue failure of metallic bolts. Mechanical fatigue involves cyclic or fluctuating tensile […]
Posted on March 30, 2015
“3D printing” or the more descriptive term – additive manufacturing (AM) – has received much publicity in recent years. What is this technology and what are some of its practical features? This blog is a summary of AM and its on-going development to make actual service components using metal alloys. Presented are selected portions of information provided in […]
Posted on January 29, 2015
Clearly it is advantageous to know when corrosion is occurring in operating equipment to avoid future failure. There is extensive literature on this topic. This post is a brief summary of information selected from the four references cited below. Each source includes several other references. It is useful to think about monitoring in two ways. […]
Posted on October 18, 2014
Often when engineers consider mechanical fatigue they envision cyclic, reversing stresses in a spinning shaft or possibly the up and down flex of aircraft wings. Rolling contact fatigue (RCF) or the associated mechanical wear is an important, closely related process to the traditional mechanism of fatigue but with distinct differences. RCF is also often known […]
Posted on January 27, 2014
Most engineers know about the danger of galvanic corrosion caused by physical contact between dissimilar metals exposed to a corrosive liquid. However, this possibility is often overlooked and other features of this type of corrosion may not be widely known. In galvanic attack the more active or electrochemically susceptible metal in the electrolyte is rapidly attacked while the […]
Posted on September 28, 2013
Aluminum alloy materials are well known for their light weight and strength-to-weight ratios. They are also susceptible to several forms of corrosion. Relative to other metals, their natural electrochemical potential places them adjacent to other very susceptible (active) metals such as magnesium (Mg) and zinc (Zn) in a traditional galvanic series in seawater. However, Al alloys […]
Posted on July 27, 2013
FMEA is a structured methodology for thoroughly thinking through and correcting potential problems in an engineering design or planned process before in-service implementation. If done well, the procedure can greatly increase reliability by reducing or eliminating failure scenarios. Ideally the procedure is completed very early in the design or planning process when relatively inexpensive corrective […]
Posted on June 26, 2013
When considering the fields of professional engineering, many in the general public are confused by the designations – material science and engineering (MSE) compared to metallurgy or metallurgical engineering. In relation to the more well- known disciplines of engineering, e.g., civil, mechanical and electrical, these materials fields have traditionally had many fewer practicing professionals and […]
Posted on May 29, 2013
Most realize that damage due to corrosion of metals is costly – but what specifically is that cost and what is included in the total? A study completed in 2002 sponsored by the Federal Highway Administration (FHWA), the National Association of Corrosion Engineers (NACE International) and implemented by CC Technologies Laboratories (now part of DVN) […]
