Elastic properties of refractory and weather resistant steel

Keywords: 09CuPCrNi-A steel, corten steel, Q345C steel plate
Do you know the elastic properties of fire and weather resistant steel? The conclusions of tensile test of refractory and weathering steel in tensile machine are as follows:
 
(1) Elastic stage It can be seen from the figure that OA is a straight line segment, indicating that the strain and stress of the test piece are proportional, so the stress at point A is called the proportional limit. When the stress exceeds the proportional limit, the stress and strain begin to lose a linear proportional relationship and transition from a straight line to a slightly curved curve AB. In the OB section, if the external force is removed, the test piece will return to its original length. This property is called the elasticity of fire-resistant and weather-resistant steel. This kind of deformation is called elastic deformation. The OB phase is called the elastic phase, and the stress corresponding to point B is called the elastic limit (.). Because the proportional limit and the elastic limit are very close (A, B points), they are often considered to be equal in practice.
 
(2) When the stress exceeds the elastic limit, the stress and strain no longer have a proportional relationship at the yield stage. At this time, the stress does not increase, but the strain rapidly increases, indicating that the refractory and weathering steel temporarily loses its ability to resist deformation. This phenomenon is called yield. This stage BC is called the yielding stage. At this time, if the external force is lost, the specimen cannot be restored to its original length. This property of the Q345C steel plate is called plasticity; the deformation that cannot be restored is called plastic deformation. In the fluctuating BC segment, C1 is called the highest value, CF is called the lowest value, and the stress corresponding to the C1 point is called the yield limit, or the yield strength and yield point, which is expressed by aK. After the fire-resistant weathering steel reaches the yield point, the deformation rapidly develops. Although the fire-resistant weathering steel has not yet been broken at this time, it can no longer meet the requirements for use. Therefore, the design point is generally the yield point erg or the lower yield point, s1. As the basis for the intensity value.
 
(3) In the strengthening phase, the refractory and weathering steel transitions from the elastic phase to the yielding phase. Its properties are transformed from elastic to plastic, and a qualitative change has occurred, reflecting the change in the internal structure of the refractory and weathering steel. Slip along the -definite crystal plane). After passing through the yield point, the internal structure of the refractory and weathering steel re-established a new balance and restored the ability to resist external forces. At this time, the curve began to rise again to the highest point D. The CD segment of the curve is called the strengthening phase. The stress corresponding to point D is called the strength limit, also known as the tensile strength, and is represented by a.
 
(4) After the necking stage reaches the apex D (ab), the strain increases significantly, and the stress gradually decreases, and the section of the specimen begins to shrink significantly. The strain increases rapidly, the stress decreases, and finally breaks at the K point. Curve DK refers to the necking fracture stage of refractory and weathering steel.