Material number G10180: 1018
G10180 is the Unified Numbering System designation for 1018, low-carbon steel, cold-finished bar (case-hardenable) specified in ASTM A29.
Reading G10180 digit by digit
A UNS designation (ASTM E527 / SAE J1086) is a letter followed by five digits. The letter G marks the alloy family — here AISI and SAE carbon and alloy steels — and the five digits 10180 place the composition inside it, usually by carrying an older AISI or SAE number forward.
What a UNS number does not carry is the product form or the property level. G10180 therefore appears in several ASTM specifications — plate, bar, pipe, forging — each with its own mechanical requirements, and the number alone is not a complete purchase specification.
G10180 identity card
| Item | Value |
|---|---|
| UNS number (ASTM E527) | G10180 |
| Symbolic grade name | 1018 |
| Steel group | G — AISI and SAE carbon and alloy steels |
| Sequential number in group | 10180 |
| Specified in | ASTM A29 |
| Steel family | Carbon steel |
| Yield, first condition in the table | ≈ 370 MPa (Cold drawn (as drawn), 16–22 mm — typical) |
| Tensile, same condition | ≈ 440 MPa |
| Cross-references held | 10 grades in 7 systems |
1018 steel (AISI/SAE 1018, UNS G10180): 0.18 % C, 0.75 % Mn low-carbon bar. Cold-drawn ≈ 370 MPa (54 ksi) yield / 440 MPa (64 ksi) tensile; hot-rolled ≈ 220/400 MPa. Composition, properties, case hardening, 1018 vs A36 vs 4140, C15/C20/S15C equivalents.
Full data sheet for 1018 → · Equivalent grades → · ASTM A29 →
UNS G — the neighbouring numbers
| UNS number | Grade | Type |
|---|---|---|
| G10100 | SAE 1010 | Low-carbon steel for cold forming, welding and case hardening |
| G10450 | 1045 | Medium-carbon steel, hardenable |
| G10950 | 1095 | High-carbon steel (spring / knife / blade steel) |
| G41300 | 4130 | Chromium-molybdenum low-alloy steel, weldable (chromoly) |
| G41400 | 4140 | Chromium-molybdenum low-alloy steel (chromoly) |
| G43400 | 4340 | Nickel-chromium-molybdenum low-alloy steel, deep hardening |
| G52986 | 52100 | High-carbon chromium bearing steel |
| G86200 | 8620 | Nickel-chromium-molybdenum case-hardening steel |
Same UNS letter, so the same alloy family. The digits generally carry an older AISI or SAE number.