Alloy Steel dealers in UAE

AISI 4130 / 25CrMo4 / EN18

AISI 4130 (25CrMo4, EN18) — chromium-molybdenum alloy steel combining good strength, weldability, and toughness for oil & gas, aerospace, and structural engineering applications.

Industries Served

Oil & Gas
Aerospace & Defense
Automotive
Petrochemical
Heavy Engineering
Power Generation
Manufacturing

Applications

  • Downhole drilling tools, crossovers, and sub-assemblies for UAE and GCC oil & gas operations
  • High-pressure hydraulic tubing and pressure vessel components in petrochemical plant
  • Aerospace structural members, fuselage frames, and aircraft undercarriage components
  • Gearboxes, drive shafts, and power transmission components in automotive and heavy machinery
  • Valve bodies, bonnets, and pressure-retaining components in oil field surface equipment
  • Racing and performance automotive components where weldability and high strength-to-weight ratio are critical
  • Structural forgings for pressure vessels and flanges in upstream oil & gas production
  • Cylinder barrels and ram bodies for hydraulic equipment in construction and industrial machinery
  • Rifle barrels, gun components, and defence industry structural applications (AMS 6345 / 6370)
  • Motorsport chassis, roll cages, and suspension components requiring TIG weldability and high fatigue resistance

Chemical Composition

0.3 %
C

Carbon

0.28 – 0.33 %

0.25 %
Si

Silicon

0.15 – 0.35 %

0.55 %
Mn

Manganese

0.4 – 0.7 %

P

Phosphorus

≤ 0.025 %

S

Sulphur

≤ 0.025 %

1.05 %
Cr

Chromium

0.9 – 1.2 %

0.2 %
Mo

Molybdenum

0.15 – 0.25 %

Typical value Range (min–max) Minimum (≥) Maximum (≤) Hover / tap for notes

Standard

ASTM A29 / A29M — current edition

Available Forms

Round Bar

Diameter range 10–500 mm. Hot-rolled or cold-drawn; peeled/ground bar available on request. Applicable standards: ASTM A29, EN ISO 683-2. Common for shafts, fasteners, and machined components.

Hot Rolled Bar

Flat, square, or rectangular sections from 10 to 150 mm thickness produced by hot rolling. As-rolled surface finish. Applicable for structural and engineering applications where close dimensional tolerance is not required.

Hot Forged Bar

Produced by open-die hot forging, 50–500 mm diameter / section. Improved (grain-refined) structure vs rolled bar. Used for large-section components, heavy shafts, and high-integrity downhole tooling. Supplied in Q&T or normalised condition.

Forging

Custom open-die, closed-die, and ring forgings — all sizes on request. EN 10204 3.1 and 3.2 certified. Lead times apply. For flanges, pressure vessel components, valve bodies, and aerospace structural parts.

Designations & Equivalents

StandardDesignationNotes
AISI / SAEAISI 4130
DIN25CrMo4
EN / Werkstoff1.7218Werkstoff-Nr.
BS708M25BS / EN (UK) designation per BS 970.
BSEN18Legacy BS 970 designation (superseded).
JISSCM430
ASTMA29 Grade 4130
ASMESA-29 Grade 4130
UNSG41300
AMSAMS 6370 / AMS 6345Aerospace specifications — AMS 6370 (bar) / AMS 6345 (tube).

Compliance & Certification

StandardStatusNotes
EN 10204 3.1SuitableEN 10204 3.1 Mill Test Certificate supplied as standard with all material.
EN 10204 3.2ConditionalEN 10204 3.2 third-party inspection available on request.
NACE MR0175 / ISO 15156Requires ConfirmationCompliant when hardness controlled to 22 HRC max — specify at order stage; hardness confirmed on MTC. AMS 6370 / AMS 6345 available for aerospace-specified material on request.
NACE MR0103Requires ConfirmationRefinery sour service — compliance subject to hardness control; confirm requirement at order stage.

Specifications

Mechanical Properties

Values are minimums unless noted; hardness is a maximum.

PropertyAISI 4130 / 25CrMo4 / EN18 — ASTM A29 / A29M — Quenched & Tempered (Q&T)DefaultAISI 4130 / 25CrMo4 / EN18 — EN ISO 683-2 — NormalisedAISI 4130 / 25CrMo4 / EN18 — EN ISO 683-2 — Annealed
Tensile Strength (UTS)range700–850 MPaTypical: 775 MPaCondition: Room temp, longitudinalNotes: Per ASTM A29 / EN ISO 683-2. Values for 25 mm dia. bar. Larger sections show lower values.620 MPaTypical: 700 MPaCondition: Room temp, longitudinalNotes: Per EN ISO 683-2 normalised condition.585 MPaTypical: 655 MPaCondition: Room temp, longitudinalNotes: Per EN ISO 683-2 annealed condition.
Yield Strength (0.2% Proof Stress)range590–740 MPaTypical: 655 MPaCondition: Room temp, longitudinalNotes: 0.2% offset method.415 MPaTypical: 500 MPaCondition: Room temp, longitudinal380 MPaTypical: 450 MPaCondition: Room temp, longitudinal
Elongationmin15 %Typical: 18 %Condition: 50 mm gauge lengthNotes: Minimum 15% per EN ISO 683-2 Q&T.18 %Typical: 22 %Condition: 50 mm gauge lengthNotes: Minimum 18%.20 %Typical: 25 %Condition: 50 mm gauge length
Reduction of Areamin55 %Typical: 63 %Condition: LongitudinalNotes: Minimum 55%.55 %Typical: 65 %Condition: Longitudinal60 %Typical: 70 %Condition: Longitudinal
Hardnessrange200–255 HBTypical: 228 HBCondition: Surface, BrinellNotes: Approx. 20–27 HRC. NACE MR0175 requires max 22 HRC (248 HB) for sour service.170–220 HBTypical: 195 HBCondition: Surface, BrinellNotes: Typical normalised range.156–197 HBTypical: 178 HBCondition: Surface, BrinellNotes: Maximum 197 HB per EN ISO 683-2 annealed.
Impact Energy (Charpy)min40 JTypical: 55 JCondition: Room temp, V-notchNotes: Longitudinal. [VERIFY — values vary by section size and tempering temperature]Notes: Not typically specified for normalised condition.Notes: Not typically specified for annealed condition.

Physical Properties

PropertyAISI 4130 / 25CrMo4 / EN18 — ASTM A29 / A29M — Quenched & Tempered (Q&T)DefaultAISI 4130 / 25CrMo4 / EN18 — EN ISO 683-2 — NormalisedAISI 4130 / 25CrMo4 / EN18 — EN ISO 683-2 — Annealed
Density20°C7.85 g/cm37.85 g/cm37.85 g/cm3
Modulus of Elasticity25°C210 GPa210 GPa210 GPa
Thermal Conductivity100°C42.3 W/m·K42.3 W/m·K42.3 W/m·K
Coefficient of Thermal Expansion20–100°C12.2 um/m·°C12.2 um/m·°C12.2 um/m·°C
Specific Heat Capacity20°C477 J/kg·K477 J/kg·K477 J/kg·K
Melting Point / RangeSolidus1420 °C1420 °C1420 °C
ENGINEERING NOTES
Weldability
Good

4130 / 25CrMo4 has excellent weldability compared to higher-carbon Cr-Mo grades. In sections up to 12 mm, it can typically be welded without preheat. For sections above 12 mm, preheat to 150–200°C is recommended. Post-weld heat treatment (PWHT) at 620–680°C is advisable for critical applications or heavy sections to relieve residual stress and restore toughness. Use low-hydrogen consumables throughout. In the normalised or annealed condition, TIG welding (GTAW) without preheat is widely practised in aerospace and motorsport fabrication. For oil & gas sour service joints, apply NACE MR0175 hardness controls post-PWHT. Recommended filler metals: ER80S-D2 is the primary GTAW (TIG) wire and can be used without preheat on thin sections, with ER80S-B2 preferred for Q&T parent metal; ER80S-D2 is also used for GMAW (MIG) structural and oil field fabrication; E8018-B2 low-hydrogen stick electrode is used for SMAW positional welding on heavier sections (preheat required >12 mm).

Machinability
Good

Best machined in the annealed condition (approx. 156–197 HB). In Q&T condition (200–255 HB), carbide tooling is recommended. Machinability approximately 70% of AISI 1212 free-machining steel — marginally better than 4140 due to lower carbon content. Sequence: rough machine in annealed condition, harden and temper, finish machine to final dimensions.

Overview

AISI 4130 (DIN 25CrMo4, Werkstoff-Nr. 1.7218, BS 708M25, legacy EN18) is a chromium-molybdenum low-alloy engineering steel containing 0.90–1.20% chromium and 0.15–0.25% molybdenum, with a lower carbon content (0.28–0.33%) than its more common counterpart 4140. This reduced carbon level gives 4130 a significant advantage in weldability — it can be welded in thinner sections without preheat — while still delivering tensile strengths of 700–850 MPa in the quenched and tempered condition. The grade exhibits excellent toughness, good fatigue resistance, and reliable through-hardening in sections up to approximately 65 mm, making it the preferred alloy steel for aerospace structural components, high-pressure tubing, oil country tubular goods (OCTG), and applications where both strength and field weldability are critical requirements.

Nifty Alloys supplies AISI 4130 / 25CrMo4 from stock in Dubai, UAE, in round bar, hot rolled bar, hot forged bar, and custom forgings. All material is supplied with EN 10204 3.1 Mill Test Certificates as standard — confirming chemical composition, mechanical properties, and full traceability to mill source. EN 10204 3.2 third-party inspection is available on request for critical project requirements. We deliver across the UAE within 24–48 hours and export to Saudi Arabia, Kuwait, Qatar, Oman, and Bahrain. Contact our team for same-day quotation and current stock availability.

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AISI 4130 (25CrMo4 / EN18) is widely used wherever high strength, weldability, and toughness must be combined. Key applications in UAE and GCC include downhole drilling tools and crossovers in oil & gas operations; high-pressure hydraulic tubing and pressure vessel components in petrochemical plants; aerospace structural members and aircraft undercarriage parts (per AMS 6345 / AMS 6370); valve bodies and flanges for surface wellhead equipment; and custom forgings for upstream oil & gas applications. In motorsport and high-performance automotive, 4130 steel tube is the standard chassis and roll cage material because it can be TIG welded without preheat and achieves excellent strength-to-weight ratios.

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