SAE 4130 Tubing
SAE 4130 and AISI 4130 are the same steel. The SAE name appears most often in automotive and motorsport documents, and SAE is also the body that publishes the AMS aerospace material specifications for this alloy.
The SAE Numbering System for Alloy Steel
The SAE four-digit numbering system encodes alloy information: the first digit indicates the major alloying category (4 = molybdenum-containing alloys; when combined with chromium, the prefix '41' identifies chromium-molybdenum steels), and the final two digits indicate nominal carbon in hundredths of a percent (30 = approximately 0.30%). SAE 4130 therefore identifies: chromium-molybdenum alloy steel with approximately 0.30% nominal carbon.
| SAE Grade | Alloy Family | Nominal Carbon |
|---|---|---|
| 4130 | Chromium-Molybdenum | ~0.30% |
| 4140 | Chromium-Molybdenum | ~0.40% |
| 4340 | Nickel-Chromium-Molybdenum | ~0.40% |
| Note | Exact limits per applicable specification — verify MTC |
SAE 4130 in Automotive and Motorsport Context
Although the SAE system originated in the automotive context, SAE 4130 tubing is used across aerospace, motorsport, and general engineering. In motorsport, it is the standard material for roll cage construction because the SAE 4130 designation — and the resulting strength characteristics in normalised condition — is explicitly referenced in NHRA, FIA, and SCCA rulebooks. Engineers referencing 'SAE 4130' on a blueprint are invoking this well-established designation regardless of the industry.
Procurement Using SAE 4130
As with AISI 4130, the SAE designation alone does not define the product form or testing requirements. A complete procurement specification for SAE 4130 tubing requires the product standard (e.g., ASTM A519), manufacturing form (Cold Drawn Seamless), dimensions (OD and wall), condition (Normalized, Annealed), and documentation (MTC 3.1). Providing only 'SAE 4130' on a purchase order will require the supplier to request clarification before quoting.
SAE Grade, AMS Specification and ASTM Standard
Three kinds of document refer to 4130, and they do different jobs.
| Document | What it defines | Example |
|---|---|---|
| SAE grade | Chemical composition of the steel | SAE 4130 |
| ASTM standard | A commercial product form with its tolerances and tests | ASTM A519, seamless mechanical tubing |
| AMS specification | An aerospace product with condition, properties and quality requirements | AMS 6360 and AMS-T-6736 for 4130 tubing |
A rulebook that says "SAE 4130" is naming the material. A drawing that says "AMS-T-6736" is naming a complete aerospace product, with required mechanical properties and inspection. The second is far more demanding than the first, so quote the exact document your project names. Aircraft requirements are discussed under 4130 aircraft tubing, and the commercial standard under ASTM A519 4130 tubing.
Frequently Asked Questions
Is SAE 4130 the same as AISI 4130?
Yes. The SAE and AISI numbering systems for steel grades are historically coordinated and produce identical designations. SAE 4130 and AISI 4130 refer to the same alloy composition.
Why does a motorsport rulebook specify SAE 4130 rather than AISI 4130?
Motorsport governing bodies (NHRA, FIA, etc.) adopted the SAE designation because SAE has historically been more closely associated with automotive and racing engineering contexts. The material itself is identical regardless of which designation prefix is used.
Is SAE 4130 tubing different from ASTM A519 4130 tubing?
SAE 4130 is the grade; ASTM A519 is a tubing standard that uses that grade. A519 Grade 4130 tube is made from SAE 4130 steel.
What is an AMS specification?
An aerospace material specification published by SAE, defining a product's condition, properties and quality requirements.
Request SAE 4130 Tubing Quotation
Supply your SAE 4130 specification including product standard, dimensions, condition, and MTC requirement.
- Grade: SAE 4130
- Product Standard (ASTM A519 / AMS-T-6736)
- OD and Wall Thickness
- Condition
- Footage / Tonnage
- MTC Requirement
- Delivery Location