Printed from Kezuriba (kezuriba.net/en/materials/aisi4130/)
4130
ISO P (steel)Chromium-molybdenum steel (low alloy steel). Number: UNS G41300. Standard: SAE J404 (composition standard; table is paywalled and not confirmed) / for aircraft, AMS 6370, 6350, 6345, 6348, 6360, etc..
🌐JIS and international equivalents
“Close” means composition or properties are not exactly the same. Before substituting, check the values in each standard.
| System | Designation | Number | Relation | Confidence |
|---|---|---|---|---|
| AISI/SAE | 4130 | UNS G41300 | — | |
| JIS | SCM430 | JIS G 4053 | close | Agrees in 2+ sources[10][11] |
| EN | 25CrMo4 | 1.7218 | close | Agrees in 2+ sources[12][13][11] |
| GB | 30CrMo30CrMoA | close | One source / reference[10] |
Differences between the equivalents (from the sources)
- JIS SCM430: Kyocera's cross-reference table lists AISI 4130 on the SCM430 row. Mitsubishi Materials' table lists JIS SCM420 and SCM430 and AISI 4130 on the 25CrMo4 (1.7218) row
- EN 25CrMo4: Saarstahl and SIJ (Ravne) datasheets also list SAE 4130. The guide composition for Saarstahl is C 0.25, Cr 1.05, Mo 0.25, with lower carbon than 4130 (C 0.28–0.33). Saarstahl states it is used for high-toughness parts in automobiles and aircraft
- GB 30CrMo: GB column of Kyocera's cross-reference table on the SCM430 row. Mitsubishi Materials' table disagrees, with 30CrMn in the GB column of the 25CrMo4 row. The composition on the GB side could not be obtained from primary sources
📄Related specifications (AMS, ASTM etc.)
Specifications called up on purchase orders and drawings. AMS are SAE aerospace material specifications, split by product form (bar, plate, forging), melting practice and heat treatment. Standard texts are paid, so only titles and scopes checked on the publishers’ public pages are shown.
| Spec | Scope | Confidence |
|---|---|---|
| AMS 6370 | Steel, Bars, Forgings, and Rings, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130)Bar, forgings and rings (including flash-welded rings and stock for forging). Aircraft quality | Agrees in 2+ sources[1] |
| AMS 6350 | Steel Sheet, Strip, and Plate, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130), Aircraft QualitySheet, strip and plate. Aircraft quality (the version seen on the page was AMS6350R) | Agrees in 2+ sources[7] |
| AMS 6345 | Steel, Sheet, Strip, and Plate 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130) Aircraft Quality, Normalized or Otherwise Heat TreatedSheet, strip and plate. Normalized or other heat-treated condition (the version seen on the page was AMS6345F) | Agrees in 2+ sources[14] |
| AMS 6348 | STEEL BARS 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130) NormalizedBar. Normalized condition (what was seen on the page was the original edition title without a revision letter) | One source / reference[15] |
| AMS 6360 | Steel Tubing, Seamless, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130), Normalized or Stress RelievedSeamless tube. Normalized or stress relieved (the version seen on the page was AMS6360M) | Agrees in 2+ sources[8] |
| AMS 6351 | Steel, Sheet, Strip, and Plate, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130), SpheroidizedSheet, strip and plate. Spheroidize annealed condition | One source / reference[16] |
| SAE J404 | Chemical Compositions of SAE Alloy SteelsSAE standard for the chemical composition of alloy steels (source of the general composition of 4130). The version seen on the page was J404_200901 | Agrees in 2+ sources[3] |
All ASTM standards on Kezuriba: ASTM standards quick reference.
✈Main aerospace uses (as stated in the sources)
- MIL-HDBK-5J: 4130 is widely used because its heat treatment and processing procedures are well established; sheet, plate and tube are available in all sizes. Bar is also used for small forgings less than 1/2in thick[2]
- AMS (SAE) specifies 4130 as aircraft quality bar, forgings and rings (AMS 6370), sheet and plate (AMS 6350, 6345) and seamless tube (AMS 6360)[1][7][8]
⚗Chemical composition (mass %)
Ranges differ between specifications, so each one has its own column (dark figures agree in several sources, light figures come from one source).
| Element | Spec ① | Spec ② |
|---|---|---|
| C | 0.28 – 0.33[1][7][8] | 0.28 – 0.33[9] |
| Mn | — | 0.4 – 0.6[9] |
| P | — | ≤ 0.03[9] |
| S | — | ≤ 0.03[9] |
| Si | — | 0.15 – 0.35[9] |
| Cr | — | 0.8 – 1.1[9] |
| Mo | — | 0.15 – 0.25[9] |
- Spec ① AMS 6370, 6350, 6345, 6348, 6360 (carbon range written in the standard titles)
- Spec ② ASTM A829 (plate. SSAB mill material, heat analysis)
⚖Density
7.83 g/cm³
One source / reference[2]
Value converted from MIL-HDBK-5J's 0.283 lb/in³ (listed in the table as a value common to low alloy steels). For reference: SIJ's 1.7218 (EN 25CrMo4) is 7.86
Calculate weight in 4130 →💪Mechanical properties
“Reference” values are not specified minimums from the standard but figures published by makers and others.
| Condition | Tensile MPa | Yield MPa | Elong. % | Hardness | Type of value |
|---|---|---|---|---|---|
| Normalized and tempered (stress relieved). Sheet, strip and tube, thickness 0.188in (4.78mm) or less. AMS 6360, 6373, 6374, AMS-T-6736, AMS-S-18729 | ≥ 655 (95ksi) | ≥ 517 (75ksi) | Per MIL-HDBK-5J Table 2.3.1.0(d) (sheet 8–18 depending on thickness, tube 10–15) | — | Design value (MIL-HDBK-5J, S-basis) One source / reference[2] |
| Normalized and tempered (stress relieved). Sheet, strip and tube, thickness over 0.188in (4.78mm) | ≥ 621 (90ksi) | ≥ 483 (70ksi) | Per MIL-HDBK-5J Table 2.3.1.0(d) | — | Design value (MIL-HDBK-5J, S-basis) One source / reference[2] |
| Quenched and tempered. Tube (AMS 6361, AMS-T-6736), wall thickness 0.188in or less, Ftu 125ksi class | ≥ 862 (125ksi) | ≥ 689 (100ksi) | ≥ 17 (round bar specimen 4D, Table 2.3.1.0(e)) | — | Design value (MIL-HDBK-5J, S-basis) One source / reference[2] |
| Quenched and tempered. Tube (AMS 6362, AMS-T-6736), wall thickness 0.188in or less, Ftu 150ksi class | ≥ 1034 (150ksi) | ≥ 931 (135ksi) | ≥ 14 (round bar specimen 4D, Table 2.3.1.0(e)) | — | Design value (MIL-HDBK-5J, S-basis) One source / reference[2] |
| Quenched and tempered. Tube (AMS-T-6736), full wall thickness, Ftu 180ksi class. The maximum diameter that can be fully hardened is 0.5in for round bar (Table 2.3.0.2) | ≥ 1241 (180ksi) | ≥ 1138 (165ksi) | ≥ 12 (round bar specimen 4D, Table 2.3.1.0(e)) | — | Design value (MIL-HDBK-5J, S-basis) One source / reference[2] |
1 MPa ≈ 145 psi (0.145 ksi). Hardness conversion · unit converter
🔧Machinability notes (as stated in the sources)
- MIL-HDBK-5J (alloy steels in general): a two-stage approach is common, with rough machining in the annealed or hot-finished condition and finishing after the final heat treatment for dimensional accuracy. After heat treatment the material is hard, so sharp tools, appropriate feeds and speeds, and ample cutting fluid are needed. Free-machining (sulfur- or lead-added) steels lose much of their transverse properties and are not recommended for high-stress aircraft parts[2]
- Sandvik Coromant: low alloy steels (alloying elements under 5%) are ISO P. Machinability is determined by alloy content and heat treatment (hardness). Hardened steels above about 45HRC fall into ISO H[4]
📚Sources
Primary sources (public documents from makers, industry associations and standards bodies), numbered where each value is cited. Many are in Japanese.
- sae.org https://www.sae.org/standards/content/ams6370/
- everyspec.com https://everyspec.com/MIL-HDBK/MIL-HDBK-0001-0099/MIL_HDBK_5J_139/
- saemobilus.sae.org https://saemobilus.sae.org/standards/j404_200901-chemical-compositions-sae-alloy-steels
- sandvik.coromant.com https://www.sandvik.coromant.com/en-us/knowledge/materials/workpiece-materials
- kyocera.co.jp https://www.kyocera.co.jp/prdct/tool/wp-content/uploads/2014/07/2024-2026_A.pdf
- sumitool.com https://www.sumitool.com/downloads/cutting-tools/general-catalog/assets/pdf/a.pdf
- sae.org https://www.sae.org/standards/content/ams6350r/
- sae.org https://www.sae.org/standards/content/ams6360m/
- ssab.com https://www.ssab.com/en-ca/brands-and-products/commercial-steel/chemistry/astm-a829
- kyocera.co.jp https://www.kyocera.co.jp/prdct/tool/wp-content/uploads/2016/06/R_2016.pdf
- mitsubishicarbide.net https://www.mitsubishicarbide.net/contents/mhg/ru/manual/material_cross_reference.pdf
- saarstahl.com https://www.saarstahl.com/app/uploads/2024/03/20160318114702-25CrMo4-.pdf
- cms.sij.si https://cms.sij.si/storage/47/file4747.pdf
- saemobilus.sae.org https://saemobilus.sae.org/standards/ams6345f-steel-sheet-strip-plate-095cr-020mo-028-033c…
- saemobilus.sae.org https://saemobilus.sae.org/standards/ams6348-steel-bars-095cr-020mo-028-033c-sae-4130-norm…
- sae.org https://www.sae.org/standards/content/ams6351/
Other materials
Aerospace steel