by Jack Stewart A dunk tester inspects an automotive radiator at a radiator repair shop. If it leaks, the bubbles show where and it can be repaired. Source: Stewart Ergonomics Inc. With many leak testing methods to choose from, which is the right one? Leak testing equipment is a type of nondestructive testing equipment [...]
The theory of airborne ultrasonic detection is relatively simple. Ultrasonic instruments are sensitive to sounds beyond the limits of normal human hearing. An ultrasonic detector translates ultrasonic signals to the range of human hearing. Frequency, the number of times a sound wave cycles from trough to crest, is expressed in Cycles per seconds and [...]
An Inspection Test Plan (ITP) is a commonly required document that you’ll need to submit with your construction quality control plan. Whether you’re working on a private sector or government contract, clients today all want to see your inspection test plan. They want to know exactly what inspections and tests you’ll be forming to control [...]
Protective coatings are the most commonly used method of corrosion control. Protective coatings can be metallic, such as the galvanized steel shown below, or they can be applied as a liquid “paint.” Most of the research and testing of protective coatings at the Kennedy Space Center is related to paint-like protective coatings. (Courtesy of www.corrosion-doctors.org) [...]
Materials Selection Most large metal structures are made from carbon steel-the world’s most useful structural material. Carbon steel is inexpensive, readily available in a variety of forms, and can be machined, welded, and formed into many shapes. This large statue by Pablo Picasso in front of the Chicago city hall is made from a special [...]
Hydrogen can cause a number of corrosion problems. Hydrogen embrittlement is a problem with high-strength steels, titanium, and some other metals. Control is by eliminating hydrogen from the environment or by the use of resistant alloys. Hydrogen blistering can occur when hydrogen enters steel as a result of the reduction reaction on a metal cathode. [...]
Galvanic Corrosion Galvanic corrosion is an electrochemical action of two dissimilar metals in the presence of an electrolyte and an electron conductive path. It occurs when dissimilar metals are in contact. It is recognizable by the presence of a buildup of corrosion at the joint between the dissimilar metals. For example, when aluminum alloys or [...]
Metals corrode because we use them in environments where they are chemically unstable. Only copper and the precious metals (gold, silver, platinum, etc.) are found in nature in their metallic state. All other metals, to include iron-the metal most commonly used-are processed from minerals or ores into metals which are inherently unstable in their environments. [...]
Overview Anodic Protection is a corrosion mitigation technique first introduced in the 1960′s in which the potential of an alloy is controlled relative to a stable reference potential in a range of values more positive or oxidizing than the corrosion potential that causes the corrosion rate to be depressed relative to that which would occur [...]
MIG welding is an abbreviation for Metal Inert Gas Welding. It is a process developed in the 1940’s, and is considered semi-automated. This means that the welder still requires skill, but that the MIG welding machine will continuously keep filling the joint being welded. MIG welders consist of a handle with a trigger controlling a [...]