Stress proof

Division 1. Below the creep range, design stresses are based on one-fourth of the tensile strength or two-thkds of the yield, or 0.2% proof stress. Design procedures are given for typical vessel components under both internal pressure and external pressure. No specific requkements are given for the assessment of fatigue and thermal stresses. 

Fig. 9. Effect of temperature on strength and ductiUty of a nickel-base superaHoy, IN-939, showing A, tensile strength B, 0.2% proof stress C, reduction in...

Yield strength or tensile proof stress the maximum stress that can be applied without permanent deformation of the test specimen. For the materials that have an elastic limit (some materials may not have an elastic region) this may be expressed as the value of the stress on... 

Proof stress (F/Aq at a permanent strain of 0.1%) (0.2% proof stress is often quoted instead. Proof stress is useful for characterising yield of a material that yields gradually, and does not show a distinct yield point.)... 

The nominal stress at yielding. In many materials this is difficult to spot on the stress-strain curve and in such cases it is better to use a proof stress. 

The stress which produces a permanent strain equal to a specified percentage of the specimen length. A common proof stress is one corresponding to 0.1% permanent strain. 

There are slight differenees between BSS and ASTM compositions. Properties in brackets are indicative, not mandatory. 0.2% proof stress. ... 

Stress below the proof stress does not normally affect corrosion rates. Cyclic stresses in combination with a corrosive environment (corrosion fatigue) can produce failure at below the ordinary fatigue limit. Alloys susceptible to intergranular attack may corrode faster when stressed (see Section 8.5). 

Type and designation Form of material 0.2% proof stress (M Pa) Tensile Sirengih (M Pa) Elongation (%) Hardness (HV)... 

Proof stress (MPa) Tensile strength (MPa) Elongation on 50 mm (<7o) Fatigue limit (% of T.S.) Bend radius Young s modulus (GPa) Density (g/cm )... 

The design stress for a material, the value used in any design calculations, is based on the tensile strength, or on the yield or proof stress (see Chapter 13). 

Proof stress is the stress to cause a specified permanent extension, usually 0.1 per cent. 

Tensile strength (N/mm2) 0.1 per cent proof stress (N/mm2) Modulus of elasticity (kN/mm2) Hardness Brinell Specific gravity... 

For materials not subject to high temperatures the design stress is based on the yield stress (or proof stress), or the tensile strength (ultimate tensile stress) of the material at the design temperature. 

Minimum yield stress or 0.2 per cent proof stress, at the design temperature 1.5 1.5 1.5... 

Figure 5.27 Stress-strain diagram indicating method for determining proof stress. From Z. Jastrzebski, The Nature and Properties of Engineering Materials, 2nd ed. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

Figure 5.28 Stress-strain diagram showing (1) modulus, (2) yield strength, (3) ultimate tensile strength, (4) ductility, and (5) toughness. Note the use of proof stress in determination of yield stress. Reprinted, by permission, from J. F. Shackelford, Introduction to Materials Science for Engineers, 5th ed., p. 190. Copyright 2000 by Prentice-Hall, Inc.

France CODAP Service de Enforced (0.2%-proof stress at... 

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