1. Chemical Composition
Table 1 – Chemical composition, unit: %
For all steel grades listed in this table, the Cu content as an impurity shall not exceed 0.30%.
Al may be added for grain refinement upon agreement between the supplier and the purchaser.
Elements not specified in this table shall not be intentionally added except for steelmaking purposes; any such addition shall be determined by agreement between the supplier and the purchaser.
Upon agreement between the supplier and the purchaser, the permissible deviations from the specified values for ladle analysis during product analysis of steel shall comply with Table 4 of JIS G 0321.
Note a) The lower limit for Si may be set to a value below 0.15% upon agreement between the supplier and the purchaser.
Al may be added for grain refinement upon agreement between the supplier and the purchaser.
Elements not specified in this table shall not be intentionally added except for steelmaking purposes; any such addition shall be determined by agreement between the supplier and the purchaser.
Upon agreement between the supplier and the purchaser, the permissible deviations from the specified values for ladle analysis during product analysis of steel shall comply with Table 4 of JIS G 0321.
Note a) The lower limit for Si may be set to a value below 0.15% upon agreement between the supplier and the purchaser.
2. Mechanical properties of wire rod
Table 2 – Mechanical properties of wire rod
| Grade | Tensile strength (N/mm²) | Reduction of area (%) | ||||
|---|---|---|---|---|---|---|
| DA1 | DA2 | DA3 | DA1 | DA2 | DA3 | |
| SMn420WCH | ≤630 | ≤600 | - | ≥53 | ≥53 | - |
3. Depth of decarburized layer
Table 3 Permissible limits for average decarburized layer depth
| Unit: mm | ||
|---|---|---|
| Diameter | Ferrite decarburized layer depth | Total decarburized layer depth |
| ≤15 | ≤0.02 | ≤0.12 |
| >15~25 | ≤0.02 | ≤0.15 |
| >25~32 | ≤0.02 | ≤0.20 |
| >32~40 | ≤0.03 | ≤0.25 |
| >40~50 | ≤0.03 | ≤0.30 |
For wire rod with a diameter exceeding 50 mm, to be agreed upon by both supplier and purchaser.
4. Hardenability
Table 5 Distance from quenched end and hardness
5. Wire diameter tolerance and out-of-roundness
Table 8 Wire diameter tolerance and out-of-roundness
| Diameter | Permissible deviation | Out-of-roundness |
|---|---|---|
| ≤15 | ±0.30 | ≤0.40 |
| >15~25 | ±0.40 | ≤0.50 |
| >25~32 | ±0.50 | ≤0.60 |
| >32~50 | ±0.60 | ≤0.70 |
Note 1) Diameter deviation refers to the difference between the maximum and minimum diameters within the same cross-section of the wire rod. For wire rods with a diameter exceeding 50 mm, this shall be subject to agreement between the supplier and the purchaser.