AISI4140 Steel Plate Applications & Ordering Guide
AISI/SAE 4140 (UNS G41400; ASTM A29 / A829 plate practice) is specified for industrial fabrications where the drawing or material list names this grade. This applications page explains where the grade is used, what service conditions drive selection, and which certificate details belong on the purchase order. Gangsteel supplies AISI/SAE 4140 with EN 10204 mill test certificates.
Typical Applications and Service Conditions
AISI/SAE 4140 plate is ordered for pressure equipment, process vessels, heat-exchanger related fabrications, structural members under the governing code, and project packages that call the grade by name. Match the mill test certificate grade mark to the calculation sheet; do not treat near-equivalents as automatic substitutes.
Service drivers include the design temperature and pressure of the governing code (ASME, EN/PED, class society, or project specification), weld procedure qualification needs, toughness or creep allowables where applicable, and inspection scope. Delivery condition Annealed, normalized, or quenched and tempered per order; A829 lists hardness by condition should be stated explicitly on the purchase order.
Industry Use Cases
Pressure equipment and process: shells, heads, and related platework when drawings name AISI/SAE 4140. Power and energy: boiler and heat-recovery fabrications under the ordered edition. Marine / offshore (when classed): only when the society material list names this exact grade stamp. Always keep heat-number traceability on cut pieces.
Chemical Composition - Supporting Data (AISI/SAE 4140)
Standard AISI 4140 heat analysis. Plate orders often cite ASTM A829 Grade 4140 - confirm condition (annealed/normalized/QT) on the PO.
| Element / rule | Requirement |
|---|
| C | 0.38-0.43 |
| Mn | 0.75-1.00 |
| Si | 0.15-0.35 |
| Cr | 0.80-1.10 |
| Mo | 0.15-0.25 |
| P, max | 0.035 |
| S, max | 0.040 |
Mechanical Properties - Supporting Data (AISI/SAE 4140)
Confirm thickness, specimen orientation, and any supplementary impact, UT, or hardness requirements on the PO.
| Property | Requirement |
|---|
| Annealed tensile (typical handbook) | ~655 MPa |
| Annealed yield (typical handbook) | ~415 MPa |
| Annealed elongation (typical) | ~25% |
| A829 annealed hardness, max | 240 HBW |
| A829 normalized hardness, max (t<=38 mm) | 320 HBW |
| Note | Final QT properties are temper-dependent - use MTC values for design |
Related / Near-Equivalent Grades
Near-equivalents are for cross-reference only. They are not automatic code substitutes. Substitution requires engineer approval and matching certificate scope.
| System | Grade | Note |
|---|
| DIN | 42CrMo4 / 1.7225 | Near European twin |
| JIS | SCM440 | Near Japanese twin |
| GB | 42CrMo | Near Chinese twin |
Frequently Asked Questions
Where is AISI/SAE 4140 typically applied?
AISI/SAE 4140 is applied where design documents, class material lists, or purchaser specs name this grade for pressure, process, structural, or marine fabrications as applicable. Match the MTC marking to the drawing.
What service conditions drive selection of AISI/SAE 4140?
Design temperature and pressure, toughness or creep allowables, weldability, corrosion or process media, and the governing code edition drive selection. Delivery condition Annealed, normalized, or quenched and tempered per order; A829 lists hardness by condition must align with the ordered specification.
Can a near-equivalent replace AISI/SAE 4140 on an applications drawing?
Not without redesign and written approval. Near-equivalents differ in chemistry, heat treatment, impact temperature, or product form. Commercial swaps create non-conformance when the dossier names AISI/SAE 4140.
What fabrication notes matter for AISI/SAE 4140?
Use approved WPS/PQR packages for the thickness and filler, control heat input, and preserve heat-number traceability on cut pieces. State any supplementary UT, PMI, or impact tests on the purchase order.
What certificate and marking should an applications PO demand?
EN 10204 3.1 is standard; 3.2 when a purchaser-appointed inspector witnesses tests. The MTC should show heat analysis, tensile results, delivery condition, and heat number aligned with AISI/SAE 4140.
How should I RFQ AISI/SAE 4140 plate from Gangsteel for a project?
Send AISI/SAE 4140 (UNS G41400; ASTM A29 / A829 plate practice), thickness x width x length (or nesting list), quantity, delivery condition, optional NDT/PMI, certificate type, destination, and any dual-mark needs. Note the end use when special flatness or cut-to-size packaging is required.
Ordering and Mill Certificates
State grade AISI/SAE 4140 (UNS G41400; ASTM A29 / A829 plate practice), dimensions, quantity, delivery condition, optional NDT/PMI, and certificate (EN 10204 3.1 standard; 3.2 when third-party inspection is ordered). Gangsteel supplies export plate and related products with mill test certificates. Contact Gangsteel for stock and mill production RFQs.
