Mechanical Properties of Metals is one of the important part on pipe systems in this case is piping materials which is contain Modulus of Elasticity (Young's Modulus), Yield Strength, Ultimate Tensile Strength, Elongation and Reduction Area, and that's all of thing will explain in this chapter only at Piping & Fabrication.
Mechanical properties are critically important to the design process. They are defined as the characteristic response of amaterial to applied force. The standardized test methods for measuring these properties are described in ASTM specifications. Properties fall into two general categories, strength and ductility. Some properties, such as material toughness, are dependent on both strength and ductility. The most widely known and used material properties, as defined by ASTM, are described in the following paragraphs.
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| FIGURE A3.2 Tension-test specimens |
Modulus of Elasticity (Young’s Modulus).
The modulus of elasticity is the ratio of normal stress to corresponding strain for tensile or compressive stresses. This ratio is linear through a range of stress, known as Hooke’s law. The material behavior in this range is elastic (i.e., if the applied load is released the material will return to its original, unstressed shape). The value of the slope in the elastic range is defined as Young’s Modulus. The modulus of elasticity is measured using the tension test, the most widely used test applied to engineering materials. The test consists of applying a gradually increasing load in either tension or compression, in a testing machine, to a standardized test specimen (Fig. A3.2). The applied load is continuously monitored, as is test specimen elongation or contraction under load. These measured quantities are generally represented on a coordinate axis, called a stress-strain curve (Fig. A3.3). The modulus of elasticity and other strength properties are established from this curve. Values of the modulus of elasticity for a number of construction materials are given in Table A3.1
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| FIGURE A3.3 Stress-strain diagram |
Yield Strength.
When a specimen is loaded beyond the point where elastic behavior can be maintained the specimen will begin to deform in a plastic manner. Most materials do not abruptly transform from purely elastic to purely plastic behavior. Rather,
