What is 4130 material equivalent to?

4130 Material Equivalent: How to Specify the “Same Steel” Across GB / JIS / DIN-EN / GOST

When a drawing or legacy PO calls out AISI/SAE 4130 (UNS G41300), the real job isn’t just “finding 4130.” It’s making sure the chemistry window + delivery condition + test requirements match what your component actually needs (strength, impact, weldability, sour service limits, etc.). 4130 is a classic Cr-Mo low-alloy steel (roughly ~0.3%C, ~1%Cr, ~0.2%Mo), and it has several close equivalents worldwide.

Closest “Equivalent Grades

Where 4130 Commonly Appears in Standards

Below is a procurement-friendly view of standards where “4130” is commonly specified—especially relevant when you’re buying tubes, bars, or forging stock.

1) Chemical composition designation (baseline identity)

• SAE chemistry designation / UNS: 4130 is commonly tracked as UNS G41300 in specs and mill test reports. 

2) Tube & pipe forms (common for mechanical tubing / lines)

• ASTM A519 / A519M (seamless mechanical tubing): commonly lists Grade 4130. 

• ASTM A513 / A513M and ASME SA-513 (ERW mechanical tubing): may also reference 4130 chemistry options depending on edition/ordering format. 

• European tube routes often convert to 25CrMo4 (1.7218) under standards such as EN 10297-1 / EN 10216-2 depending on application and purchaser requirements. 

3) Bars / forgings / rings (typical upstream stock for machining)

• ASTM A29 / A29M and ASTM A322 are frequently used frameworks for hot-wrought bars (with grade tables and general requirements handled across these documents). 

• Aerospace / high-cleanliness material specs often call out 4130 under AMS families (see next).

4) Aerospace-quality 4130 (if cleanliness / QA is strict)

• SAE AMS6370S explicitly covers aircraft-quality 4130-type steel in bars/forgings/rings/stock. 

• 4130 is also widely referenced in aircraft material datasheets tied to AMS 6345 / 6346 / 6350.

5) Oil & gas / wellhead-style use (where toughness + SSC matters)

• 4130-type Cr-Mo steels are widely used for wellhead applications, but you must manage hardenability limits, section size, and sour-service rules. 

• For H₂S / sour service, specifications frequently require alignment with NACE MR0175 / ISO 15156, including hardness limits and sometimes SSC qualification. 

Three Practical Expansion Questions (and Straight Answers)

Q1) “If 4130 ≈ 25CrMo4 / 30CrMo / SCM430 / 30KhMA, can I swap them directly?”

Answer: Only if you control the whole technical package, not just the name. Equivalency tables are typically chemistry-based; your part performance is usually condition-based (Normalized vs Quenched & Tempered vs Annealed). Even within the “equivalent” family, manganese, silicon, and residual limits can shift, which affects hardenability, impact toughness, and weld procedure sensitivity. Use the equivalent grade as a starting point, then lock down: heat treatment, tensile/yield, hardness range, Charpy (if needed), and NDE. 

Q2) “Which standard should I reference when I’m buying tubes—A519, EN tube standards, or something else?”

Answer: Choose the standard that matches product form + intended use:

• If you’re buying seamless mechanical tubing, ASTM A519 is a common North American callout for Grade 4130. 

• If you’re buying to European supply chains, you’ll often buy 25CrMo4 (1.7218) under EN tube standards and specify delivery condition (e.g., +QT). 

• If the tubing is for pressure-containing service, you may need additional code alignment (design code, impact rules, traceability, etc.) beyond the material standard—so write the PO to include those supplemental requirements.

Q3) “What changes when the service is H₂S / sour, or when toughness is critical?”

Answer: Sour service is where “close equivalent” can get expensive—fast. Many sour-service requirements hinge on hardness caps and SSC resistance validation. A commonly referenced rule set (MR0175/ISO 15156 context) often drives a maximum hardness (e.g., 22 HRC in many low-alloy cases), with certain allowances (e.g., up to ~26 HRC in specific tubular contexts) only when qualified by SSC testing. That means your 4130/25CrMo4/SCM430 choice must be paired with the right heat treatment window and verified hardness and SSC requirements.