By hardness is understood as a property of the material to resist indentation therein of other, more rigid.In the proccess durometer hardness -indentor tip made of a very hard material (diamond, hard metal et al.), Pressed into the material under investigation with a specific predetermined load, the results of which fingerprint on the sample are assessing the hardness of the test material.
Indicators derived from the measurement of hardness can determine the presence or absence of the details of hardened zones as a result of welding / heat treatment associated with changes in the structure of the cross section of the metal parts, and draw preliminary conclusions and other mechanical properties of the metal. In some cases, in terms of hardness can predict the reliability of the welded joint / items.
Applied to evaluate the mechanical strength of the weld metal, weld metal and heat affected zone. For this special use samples that are cut directly from the welded joint, or from the product made from the material and technology used during the manufacture of the weld constructions. By nature biasing mechanical tests are divided into:
- Static, in which the force increases smoothly for a long time or remains constant.
- Impact (dynamic), at which the force increases almost instantly and operates short time.
- Cyclic (fatigue), in which the load is repeatedly (from tens of millions of cycles) varies in magnitude and sign.
Spectral analysis - a set of qualitative and quantitative methods for determining the composition of the object, based on the study of the spectra of the interaction of matter with radiation, including the spectrum of electromagnetic radiation, acoustic waves on the distribution of mass and energy of elementary particles and others.
Spectral analysis - a sensitive method and is widely used in analytical chemistry, astrophysics, metallurgy, engineering, geological exploration, archeology and other branches of science.
Depending on the purpose of analysis and types of spectra identify several methods of spectral analysis. Atomic and molecular spectral analysis allow to determine the elemental and molecular composition of matter, respectively. In the emission and absorption methods composition is determined by the emission and absorption spectra. Mass spectrometric analysis is carried out on the mass spectrum of atomic or molecular ions and allows to determine the isotopic composition of the object.
In recent years, the most widely used emission and mass spectrometric methods of spectral analysis based on the excitation of atoms and their ionization in the argon plasma induction discharges, as well as in a laser spark. In theory, signal processing, spectral analysis also implies an analysis of the energy distribution of the signal (eg, audio) from the frequencies, wave numbers, and so on.