AWS A1.1 pdf free download

AWS A1.1 pdf free download.Metric Practice Guide for the Welding Industry.
2.2 Coherence. Coherence requires that all derived units in the system be obtained from the base units by the rules of multiplication and division with no numerical factor other than the number one (1) ever occurring in the expressions for derived units in terms of the base units. The system of units must also be coherent with its corresponding system of quantities and equations. A system of units is coherent with respect to a system of quantities and equations if the system of units is chosen in such a way that the equations between numerical values have exactly the same form (including numerical factors) as the corresponding equations between quantities.
2.3 Uniqueness. Uniqueness requires that there be one, and only one, unit defined for each quantity. For exarmple, the SI units for force (newton), energy (joule), and power (watt) are the same, respectively, whether the process is mechanical, electrical, or thermal. 2.4 Advantages of the SI. The International System of Units (SI) is the metric system of units in its latest form. SI is the only system of units which fully satisfies all the above three requirements for completeness, coherence, and uniqueness. Within SI, a set of base-ten prefixes is defined to form decimal multiples and submultiples of SI units. SI Units and their base-ten multiples and submultiples are in harmony with our decimal system of arithmetic, facilitating easy numerical calculations. Awkward manipulations of common fractions such as 1/16, 1/32, and 1/64 are completely unncessary. All industrial nations, including the United States by the Omnibus Trade and Competitiveness Act of 1988 (Public Law 100- 418), have chosen the SI as the preferred system of units for all applications in science, engineering, technology, commerce, and trade.
3. SI Units and Symbols SI consists of seven base units, derived units, and a set of prefixes for the formation of multiples of the various units. 3.1 SI Base Units. Names of SI base quantities, names of corresponding SI base units, their symbols, and definitions are given in Table 1. 3.2 SI Derived Units. SI derived units are formed as described in 2.2. Some of them have been given special names and symbols. Examples are listed in Table 2. 3.3 Prefixes. SI prefixes may be used to indicate multiples of SI units, thus simplifying numeric terms and providing a convenient substitute for writing powers of ten as generally preferred in computation. For example, 16 800 meters or 16.8 x 103 meters becomes 16.8 kilometers. See Table 3 for the list of prefixes and 6.1 for examples of their use. The kilogram is the only SI base or derived unit whose name, for historical reasons, contains a prefix. In this case, the appropriate prefix is attached to gram. 4. Other Units Used with SI There are certain units, although not part of SI, which are in widespread use and are acceptable for use with SI. See Table 4 for examples.
5. Units Pertaining to Welding Table 5 lists the recommended SI multiples to be used in welding nomenclature. The selection of these terms was based on use of(1) SI units where practicable, (2) numbers of reasonable size, and (3) accepted units currently in use. Filler metal and fllet sizes are tabulated in Tables 6 and 7. SI values are approximate equivalents for conversion on draw- ings, specifications, and so forth. These values are for conversion only and are not intended for new designs where a more rational series for sizing, such as shown in the Rational Series column of Table 7, may be used.AWS A1.1  pdf download.