Cart
0
Product
Products
(empty)
No products
To be determined
Shipping
$0.00
Total
Product successfully added to your shopping cart
Quantity
Total
There are 0 items in your cart.
There is 1 item in your cart.
Total products
Total shipping
To be determined
Total
Reduced price!
View larger
View larger
ASME STP-PT-076
New product
ASME STP-PT-076 2015 Edition, June 26, 2015 HANDLING OF DIFFERENCES IN YS, UTS, AND CREEP RUPTURE STRENGTH BETWEEN ASME AND OTHER STANDARDS (EN, AS, ETC.)
More info
Description / Abstract:
INTRODUCTION AND GENERAL ASPECTS
The usual procedure for assigning allowable stress values to a non-ASTM-standard material that is being introduced into the ASME code is to apply the trend curves for yield stress, ultimate tensile stress, and creep-evaluations developed for the equivalent ASTM material, anchored to the minimum specified tensile stress and yield stress contained in the non-ASTM standard. This procedure can lead to considerable discrepancies in the allowable stress values for the same basic material when comparing ASME with other codes and standards. In an international environment, such discrepancies inevitably lead to questions about the basis for the ASME stress values, as demonstrated recently by inquiries from Australia regarding the allowable stress values for certain carbon steels (Record 07-914 [1]). As yield stress (Y-1), ultimate tensile stress (U), and creep values are usually taken for the determination of stress allowables, such discrepancies can have two consequences: When the ASME allowables are below the local (EN, AS, etc.) design parameters some designs might become locally non-conservative; when the local allowables (EN, AS, etc.) are below the ASME allowables local authorities might argue ASME-based designs are non-conservative because the locally valid mechanical properties are lower. The situation becomes even more complex when temperature dependent crossovers occur, as shown in Figure 1-1 [2]. A basic understanding of differences between ASME code and other codes and standards is very important for code harmonization efforts, like the Multinational Design Evaluation Programme MDEP [3], or in relation to other pressurized component design documents, like the Pressure Equipment Directive (PED) [4]. An example of a European comparison of ASME data with respect to PED is shown in Figure 1-2 [5].
The objective of this report is to:
Possible explanations for differences between the various codes include the following.
The usual procedure for assigning allowable stress values to a non-ASTM-standard material that is being introduced into the ASME code is to apply the trend curves for yield stress, ultimate tensile stress, and creep-evaluations developed for the equivalent ASTM material, anchored to the minimum specified tensile stress and yield stress contained in the non-ASTM standard. This procedure can lead to considerable discrepancies in the allowable stress values for the same basic material when comparing ASME with other codes and standards. In an international environment, such discrepancies inevitably lead to questions about the basis for the ASME stress values, as demonstrated recently by inquiries from Australia regarding the allowable stress values for certain carbon steels (Record 07-914 [1]). As yield stress (Y-1), ultimate tensile stress (U), and creep values are usually taken for the determination of stress allowables, such discrepancies can have two consequences: When the ASME allowables are below the local (EN, AS, etc.) design parameters some designs might become locally non-conservative; when the local allowables (EN, AS, etc.) are below the ASME allowables local authorities might argue ASME-based designs are non-conservative because the locally valid mechanical properties are lower. The situation becomes even more complex when temperature dependent crossovers occur, as shown in Figure 1-1 [2]. A basic understanding of differences between ASME code and other codes and standards is very important for code harmonization efforts, like the Multinational Design Evaluation Programme MDEP [3], or in relation to other pressurized component design documents, like the Pressure Equipment Directive (PED) [4]. An example of a European comparison of ASME data with respect to PED is shown in Figure 1-2 [5].
The objective of this report is to:
-
Identify and address discrepancies between ASME-data, as reflected in the stress tables in Section II/D, and data from other codes and standards (EN, AS, etc.). -
Propose action for resolving the discrepancies (either provide technical arguments to explain the valid basis for the differences, or make recommendations for revising the stress tables).
Possible explanations for differences between the various codes include the following.
-
Differences in chemical composition -
Differences in production/heat-treatment -
Differences in definition of values (mean, lower-bound, minimum, etc.) -
Different datasets -
Different definitions of RT reference -
Different testing conditions [6] -
Different parametrizations (Larson-Miller, Manson-Haferd, etc.).