Are you aware of the Unified Numbering System (UNS)? This is a system that is meant to correlate the many metal alloy numbering systems that are being used in our country. I could go into a long discussion on this, but I believe that a simple table will give you enough information for now. Figure 11.1 shows you the various categories of alloys. If you look to the left of the table, you will see letters. The letters are the beginning for understanding types of alloys. For example, if a rating starts with the letter C, it is referring to copper. Seeing a letter F at the beginning of a rating indicates cast-iron.
Metric sizes are common in many places of the world. Plumbers in the United States still work primarily with customary measurements in terms of inches. However, you may find times when metric equivalents are useful. For this reason, I’m providing Figure 11.2
201
|
The first letter (followed by five digits) |
Alloy category (assigned to date) |
|
Axxxxx |
Aluminum and its alloys |
|
Cxxxxx |
Copper and its alloys |
|
Exxxxx |
Rare-earth metals, and similar metals and alloys |
|
Fxxxxx |
Cast irons |
|
Gxxxxx |
AISI and SAE carbon and alloy steels |
|
Hxxxxx |
AISI and SAE H-steels |
|
Jxxxxx |
Cast steels (except tool steels) |
|
Kxxxxx |
Miscellaneous steels and ferrous alloys |
|
Lxxxxx |
Low-melting metals and their alloys |
|
Mxxxxx |
Miscellaneous nonferrous metals and their alloys |
|
Nxxxxx |
Nickel and its alloys |
|
Pxxxxx |
Precious metals and their alloys |
|
Rxxxxx |
Reactive and refractory metals and their alloys |
|
Sxxxxx |
Heat — and corrosion-resistant steels (including stainless), valve steels and iron-based “superalloys” |
|
Txxxxx |
Tool steels (wrought and cast) |
|
Wxxxxx |
Welding filler metals |
|
Zxxxxx |
Zinc and its alloys |
FIGURE 11.1 ■ UNS metal family designations. (Courtesy of McGraw-Hill) for your use in comparing common measurements from the United States to metric measurements.
Threaded rods are often used to hang various types of pipe. If the size of the threaded pipe is too small in diameter and in its ability to support a proper amount of weight, the use of the rod can be very destructive. If you have a need to choose threaded rod for hanging pipe, you should find the information in Figures 11.3 and 11.4 very helpful.
