Metal testing

Last updated

Metal testing is a process or procedure used to check composition of an unknown metallic substance. There are destructive processes and nondestructive processes. Metal testing can also include, determining the properties of newly forged metal alloys. With many chemical-property databases readily available, identification of unmarked pure, common metals can be a quick and easy process. Leaving the original sample in complete, re-usable condition. This type of testing is nondestructive. When working with alloys (forged mixtures) of metals however, to determine the exact composition, could result in the original sample being separated into its starting materials, then measured and calculated. After the components are known they can be looked up and matched to known alloys. The original sample would be destroyed in the process. This type of testing is destructive.

Contents

Destructive testing (DT)

In this kind of testing, the material undergoes mechanical testing and is discarded thereafter. Test results are compared with specifications. Subtypes include:

Nondestructive testing (NDT)

Raw and finished material undergoes testing according to code specifications such as ASME Boiler and Pressure Vessel Code Section V. The tested material is not damaged by the test. Subtypes include:

See also

Related Research Articles

<span class="mw-page-title-main">Wire bonding</span> Technique used to connect a microchip to its package

Wire bonding is the method of making interconnections between an integrated circuit (IC) or other semiconductor device and its packaging during semiconductor device fabrication. Although less common, wire bonding can be used to connect an IC to other electronics or to connect from one printed circuit board (PCB) to another. Wire bonding is generally considered the most cost-effective and flexible interconnect technology and is used to assemble the vast majority of semiconductor packages. Wire bonding can be used at frequencies above 100 GHz.

<span class="mw-page-title-main">Nondestructive testing</span> Evaluating the properties of a material, component, or system without causing damage

Nondestructive testing (NDT) is any of a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. The six most frequently used NDT methods are eddy-current, magnetic-particle, liquid penetrant, radiographic, ultrasonic, and visual testing. NDT is commonly used in forensic engineering, mechanical engineering, petroleum engineering, electrical engineering, civil engineering, systems engineering, aeronautical engineering, medicine, and art. Innovations in the field of nondestructive testing have had a profound impact on medical imaging, including on echocardiography, medical ultrasonography, and digital radiography.

<span class="mw-page-title-main">Inspection</span> Organized examination or formal evaluation exercise

An inspection is, most generally, an organized examination or formal evaluation exercise. In engineering activities inspection involves the measurements, tests, and gauges applied to certain characteristics in regard to an object or activity. The results are usually compared to specified requirements and standards for determining whether the item or activity is in line with these targets, often with a Standard Inspection Procedure in place to ensure consistent checking. Inspections are usually non-destructive.

Dye penetrant inspection (DP), also called liquid penetrate inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to check surface-breaking defects in all non-porous materials. The penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous components magnetic-particle inspection is often used instead for its subsurface detection capability. LPI is used to detect casting, forging and welding surface defects such as hairline cracks, surface porosity, leaks in new products, and fatigue cracks on in-service components.

<span class="mw-page-title-main">Magnetic particle inspection</span> Non-destructive method used to detect defects in ferrous materials

Magnetic particle Inspection (MPI) is a nondestructive testing (NDT) process for detecting surface and shallow subsurface discontinuities in ferromagnetic materials such as iron, nickel, cobalt, and some of their alloys. The process puts a magnetic field into the part. The piece can be magnetized by direct or indirect magnetization. Direct magnetization occurs when the electric current is passed through the test object and a magnetic field is formed in the material. Indirect magnetization occurs when no electric current is passed through the test object, but a magnetic field is applied from an outside source. The magnetic lines of force are perpendicular to the direction of the electric current, which may be either alternating current (AC) or some form of direct current (DC).

<span class="mw-page-title-main">Plastic welding</span> Welding of semi-finished plastic materials

Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat. Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. Numerous welding methods have been developed for the joining of semi-finished plastic materials. Based on the mechanism of heat generation at the welding interface, welding methods for thermoplastics can be classified as external and internal heating methods, as shown in Fig 1.

Eddy-current testing is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

<span class="mw-page-title-main">Ultrasonic testing</span> Non-destructive material testing using ultrasonic waves

Ultrasonic testing (UT) is a family of non-destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. In most common UT applications, very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz, and occasionally up to 50 MHz, are transmitted into materials to detect internal flaws or to characterize materials. A common example is ultrasonic thickness measurement, which tests the thickness of the test object, for example, to monitor pipework corrosion.

The unified numbering system (UNS) is an alloy designation system widely accepted in North America. Each UNS number relates to a specific metal or alloy and defines its specific chemical composition, or in some cases a specific mechanical or physical property. A UNS number alone does not constitute a full material specification because it establishes no requirements for material properties, heat treatment, form, or quality.

<span class="mw-page-title-main">Industrial radiography</span> Type of non-destructive testing

Industrial radiography is a modality of non-destructive testing that uses ionizing radiation to inspect materials and components with the objective of locating and quantifying defects and degradation in material properties that would lead to the failure of engineering structures. It plays an important role in the science and technology needed to ensure product quality and reliability. In Australia, industrial radiographic non-destructive testing is colloquially referred to as "bombing" a component with a "bomb".

<span class="mw-page-title-main">Metallurgical assay</span> Compositional analysis of an ore, metal, or alloy

A metallurgical assay is a compositional analysis of an ore, metal, or alloy, usually performed in order to test for purity or quality.

In the field of industrial ultrasonic testing, ultrasonic thickness measurement (UTM) is a method of performing non-destructive measurement (gauging) of the local thickness of a solid element based on the time taken by the ultrasound wave to return to the surface. This type of measurement is typically performed with an ultrasonic thickness gauge.

The ASME Boiler & Pressure Vessel Code (BPVC) is an American Society of Mechanical Engineers (ASME) standard that regulates the design and construction of boilers and pressure vessels. The document is written and maintained by volunteers chosen for their technical expertise. The ASME works as an accreditation body and entitles independent third parties to inspect and ensure compliance to the BPVC.

Metallurgical failure analysis is the process to determine the mechanism that has caused a metal component to fail. It can identify the cause of failure, providing insight into the root cause and potential solutions to prevent similar failures in the future, as well as culpability, which is important in legal cases. Resolving the source of metallurgical failures can be of financial interest to companies. The annual cost of corrosion in the United States was estimated by NACE International in 2012 to be $450 billion a year, a 67% increase compared to estimates for 2001. These failures can be analyzed to determine their root cause, which if corrected, would save reduce the cost of failures to companies.

An Electrochemical Fatigue Crack Sensor (EFCS) is a type of low cost electrochemical nondestructive dynamic testing method used primarily in the aerospace and transportation infrastructure industries. The method is used to locate surface-breaking and slightly subsurface defects in all metallic materials. In bridge structures, EFCS is used at known fatigue susceptible areas, such as sharp-angled coped beams, stringer to beam attachments, and the toe of welds. This dynamic testing can be a form of short term or long term monitoring, as long as the structure is undergoing dynamic cyclic loading.

Microwave imaging is a science which has been evolved from older detecting/locating techniques in order to evaluate hidden or embedded objects in a structure using electromagnetic (EM) waves in microwave regime. Engineering and application oriented microwave imaging for non-destructive testing is called microwave testing, see below.

Active thermography is an advanced nondestructive testing procedure, which uses a thermography measurement of a tested material thermal response after its external excitation. This principle can be used also for non-contact infrared non-destructive testing (IRNDT) of materials.

<span class="mw-page-title-main">HY-80</span> Alloy steel

HY-80 is a high-tensile, high yield strength, low alloy steel. It was developed for use in naval applications, specifically the development of pressure hulls for the US nuclear submarine program and is still currently used in many naval applications. It is valued for its strength to weight ratio.

<span class="mw-page-title-main">Inconel 625</span> Nickel-based superalloy

Inconel Alloy 625 is a nickel-based superalloy that possesses high strength properties and resistance to elevated temperatures. It also demonstrates remarkable protection against corrosion and oxidation. Its ability to withstand high stress and a wide range of temperatures, both in and out of water, as well as being able to resist corrosion while being exposed to highly acidic environments makes it a fitting choice for nuclear and marine applications.

A variety of non-destructive examination (NDE) techniques are available for inspecting plastic welds. Many of these techniques are similar to the ones used for inspecting metal welds. Traditional techniques include visual testing, radiography, and various ultrasonic techniques. Advanced ultrasonic techniques such as time of flight diffraction (TOFD) and phased-array ultrasonics (PAUT) are being increasingly studied and used for inspecting plastic pipeline welds. Research in the use of optical coherence tomography (OCT) and microwave reflectrometry has also been conducted.

References