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Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited on ...
Higher boron content leads to higher hardness because of the increased density of short, covalent boron-boron and boron-metal bonds. However, researchers have been able to push WB 2 into the superhard regime through minority additions of other transition metals such as niobium and tantalum in the crystal structure. [ 54 ]
Many metals and thermoplastics can be welded, but some are easier to weld than others (see Rheological weldability). A material's weldability is used to determine the welding process and to compare the final weld quality to other materials. Weldability is often hard to define quantitatively, so most standards define it qualitatively.
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels .
SAW as an example can temper previous weld passes due to its generally high heat input characteristics. The detailed hardness profiles of HY-80 weldments varies with different processes (gradients vary dramatically), but the peak values for hardness remains constant among the different processes. [1] This holds true for both HAZ and weld metal.
Composition control of weld metal is often performed to maximise the volume fraction of acicular ferrite due to the toughness it imparts. During continuous cooling, higher alloy contents or faster cooling generally delay transformation, which will then take place at lower temperatures, below the bainite start temperature, and lead to higher ...
The hardenability of a ferrous alloy is measured by a Jominy test: a round metal bar of standard size (indicated in the top image) is transformed to 100% austenite through heat treatment, and is then quenched on one end with room-temperature water. The cooling rate will be highest at the end being quenched, and will decrease as distance from ...
In welding, equivalent carbon content (C.E) is used to understand how the different alloying elements affect hardness of the steel being welded. This is then directly related to hydrogen-induced cold cracking , which is the most common weld defect for steel, thus it is most commonly used to determine weldability .