Preforming / Breaking load（Grade）
06.15.2021 Wire Rope
Preforming
Preforming is a method for lessening the springiness of the rope by giving each strand and wire a form in advance.
Ropes made through this method are called preformed, or Tru-lay ropes. The strands and wires do not fall apart even when the rope is cut.
The ropes being manufactured, at present, are practically all preformed ropes. Apart from the 6×61, the non-preformed ropes are only for special uses.
Breaking load（Grade）
For the breaking load, there is the designated breaking load and the nominal breaking load.
The designated breaking load is the standard value, or the lowest value of the breaking load, while the nominal breaking load is the lowest value at the time the test pieces break.
The breaking load is determined by the nominal tension of the wires making up the rope and is classified as shown in Table 2.
Apart from these, this company will make ropes that exceed the trengths shown, on request.
Table 2・Grade of wire rope
| Standard | Grade | Summary |
| JIS G 3525 | Grade E（1320Ｎ／mm2｛135ｋｇｆ／mm2｝Class） | Bright and galvanized |
| Grade G（1470Ｎ／mm2｛150ｋｇｆ／mm2｝Class） | Galvanized | |
| Grade A（1620Ｎ／mm2｛165ｋｇｆ／mm2｝Class） | Bright and galvanized | |
| Grade B（1770Ｎ／mm2｛180ｋｇｆ／mm2｝Class） | Bright and galvanized | |
| —– | Grade special（1910Ｎ／mm2｛195ｋｇｆ／mm2｝Class） | Bright |
Cooperated by：Tokyo Rope Manufacturing