Capacity of fire hydrant valve component material is related to the most severe service condition it can sustain without a change which will prevent the fire hydrant valve component from continuing its intended function, in most case, loads are the main manifestations of capacity. to assess the load-carrying capacity of the fire hydrant valve component castings suppliers material, here we shall discuss the capacity of engineering materials to sustain loads.
A most informative material test for fire hydrant valve component castings is the simple tensile test. A specimen in the form of a cylindrical bar, machined to a displacement(extension) are recorded. the resulting load-displacement curve for a typical gray iron casting material for cast iron fire hydrant valve component. Assuming constant cross-section of the rod. the same curve related stress and strain. the curve of this figure does not correspond exactly to the real stress-strain relationship because of the way it is made, that is, we measure force and displacement at interpret them as stress and strain based on the initial length and the initial cross section of the test specimen, these properties continusly change during the experiment therefor the result of such a test will have only a formal value.
For Most material used for China fire hydrant valve component casting design from this diagram we observe a linear stress strain relationship which extends upto some point, and shortly thereafter one can observe an increasing deformation without a proportional increase in the load and the stress, this roughtly corresponds to the point that we have s substantial yielding of the material and we call this the "yield point". the corresponding stree is called the "yield strength" of the material of fire hydrant valve component casting, we have been intentionally vague in the precise definition of the yield point owing to the fact that in most materials of fire hydrant component castings it is not possible to identify a simple point where we have the transition from elastic to plastic behavior, in fact in most fire hydrant component materials this transition is not abrupt and it is a matter of definition to specify the yield point.usually we define the yield point as the point where a certain percentage of plastic deformation remain after load.
原创文章，转载请注明： 转载自DLFT CO.,LTD