The ability to identify metal is a valuable skill for many operations such as welding, machining, cutting, and fabricating. Metal workers use various methods, from traditional to modern ones, to identify the scraps and sheets of metals that come into the shop. In this post, we will explore some well-known traditional and modern metal Identification methods as well as the pros and cons of using them.
Traditional Testing Method
Some popular traditional testing methods are Appearance, Spark, Rockwell, and Brinell Harness. Generally, the benefit of these tests is that they are the cost-efficiency but the disadvantages include the strong dependency on personnel experience and the methods could damage the samples.
The appearance test does not always provide sufficient information but it could provide enough information to classify the metal. This test considers the color of metal and the existence of a machined mark or lack of one on the surfaces of the metal.
Spark test is conducted by allowing a piece of metal to touch the high-speed portable or stationary grinder with enough pressure to create a spark of stream. An experienced metal worker visually inspects the spark stream to identify the metals and considers the length, color and form of the spark stream before identifying the metal.
When using this visual spark testing technique, we recommend reserving this test to experienced technicians. At Verichek, we offer metal testing services as well as sales of metal testing instruments. When a client requests a spark test, only the most experienced and qualified technicians at Verichek are dispatched for the assignment.
A Rockwell hardness-testing machine is needed to perform this test. The point of this method is to measure the depth of an indentation made by a cone-shaped point in the testing machine. This specific test is limited as it reveals only one of many metal properties – which is hardness of the metal. Soft metals will have deeper indentation and hard metals will have lighter impression.
Brinell Harness Test
Brinell harness test is similar to the Rockwell as they both evaluate the metal impression left by an intended object. The Brinell harness test is different in that it measures the area of impression. A harden ball is forced onto the metal surface under a 3,000 kg load to create an impression. The impressed area is then measured and given a hardness number. A large impressed area indicates softer metal, which means lower hardness number.
Modern Metal Testing Methods
No longer relying on just the eye or the personal experience, modern metal testing methods incorporate technology to improve the process speed and result accuracy while protecting the samples. One popular technique is called the Positive Metal Identification (PMI) that uses X-ray Fluorescence (XRF) and Optical Emission Spectrometry (OES). PMI is the analysis of metallic alloy to establish its composition and alloy grade identification by reading the quantities by percentage of its elements. PMI analyzers provide detailed element analysis of materials for uses from industrial to research.
X-Ray Fluorescence and Optical Emission Spectrometry
Both XRF and OES techniques are widely used in the industry because they provide accurate results within seconds of testing. There are slight differences in the techniques as explained below.
XRF spectrometer excites a sample with high-energy X-rays forcing the sample to emit certain characteristic rays which are read by the XRF spectrometer. On the other hand, Optical Emission Spectrometry (OES) is also known as Atomic Emission Spectrometry uses the intensity of light emitted at a particular wavelength to determine the elemental composition of a sample. Like fingerprints, emission of rays and light are unique to metal type.
Unlike traditional methods where it takes years of training, metal workers armed with PMI spectrometers can be trained and begin working on their assignments in minutes.
Laser Induced Breakdown Spectrometer (LIBS)
Laser-induced breakdown spectrometer (LIBS) is a form of Atomic Emission Spectrometry but it uses a highly energetic laser pulse to excite the sample. This technique is also considered non-destructive to samples and is popular in scrap metal analysis.
At Verichek, our mPulse is a handheld LIBS that can analyze any metal types within 1 second. The mPulse releases laser causing a high temperature plasma on the surface of the sample and the light generated indicates the composition of the sample. This is a point-and-shoot process that provide fast and accurate results!
With modern testing techniques like Positive Metal Identification, you can minimize your working time and maximize your profit whereas traditional metal testing methods can only provide general information on your samples. From handheld spectrometers to bench-top lab OES and mobile OES, you can shop our inventory for metal analyzers. For those with a budget, our used metal analyzers are affordable and have been tested for quality.
If you’re not sure which metal analyzer is the best fit for your job, speak to one of our spectrometer experts today for a professional recommendation. We also provide metal testing services and product support for businesses throughout North America. Contact us today if you are in need for spectrometer repair or professional PMI service.