Forging
Forged at roughly 420 – 500 °C with heated dies. The alloy fills deep cavities well, which is why it suits intricate suspension and steering parts.
Automotive forging and extrusion alloy
6151 T6 Aluminium for Automotive Parts
6151 is a heat-treatable Al-Mg-Si alloy with a deliberate chromium addition, developed mainly for intricate die forgings and also extruded into forging stock and bar. In T6 it gives tensile strength in the low 300s MPa, good corrosion resistance and excellent die-fill. Metline supplies 6151 extruded bar, forging stock and finished forged or machined parts for vehicle programmes worldwide.
- Alloy
- 6151 (UNS A96151)
- Temper
- T6, also T4 / T452
- Typical T6 strength
- Rm ≈ 330 / Rp0.2 ≈ 295 MPa
- Standards
- ASTM B247 · AMS 4125
What is 6151 aluminium?
6151 is a 6xxx alloy with higher silicon than 6061 and a chromium content of 0.15 – 0.35 %. The excess silicon improves fluidity of the metal in the die during hot forging, so thin ribs and deep pockets fill completely, while chromium controls grain growth during forging and solution treatment. After T6 heat treatment it develops moderate-to-high strength with good resistance to general and stress corrosion.
Most 6151 is used as forgings, which is why ASTM B247 and AMS 4125 (die forgings and rolled rings) are its main product specifications. In the automotive supply chain it appears as extruded or cast forging stock that is cut into slugs, forged, heat-treated and machined, and occasionally as extruded bar for machined parts.
Older catalogue pages sometimes quote 6151-T6 tensile strengths approaching 500 MPa. That is not realistic for this alloy: 6151-T6 sits close to 6061-T6. If a part genuinely needs 450 MPa or more, a 7xxx alloy or a high-strength 6xxx forging alloy with copper is the right starting point.
6151 chemical composition (wt %)
Registered Aluminum Association limits, used by ASTM B247:
| Element | Minimum | Maximum |
|---|---|---|
| Silicon (Si) | 0.6 | 1.2 |
| Iron (Fe) | — | 1.0 |
| Copper (Cu) | — | 0.35 |
| Manganese (Mn) | — | 0.20 |
| Magnesium (Mg) | 0.45 | 0.8 |
| Chromium (Cr) | 0.15 | 0.35 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Nominal composition is about 0.9 % Si, 0.6 % Mg and 0.25 % Cr. The high permitted iron is rarely used in full; low-iron melts give better toughness and machined finish.
6151 mechanical properties
| Condition | Tensile strength | Yield strength (0.2 %) | Elongation | Hardness |
|---|---|---|---|---|
| T6, typical (ASM) | about 330 MPa / 48 ksi | about 295 MPa / 43 ksi | about 17 % | about 100 HB |
| T6 die forging, ASTM B247 minimum (parallel to grain flow) | 303 MPa / 44 ksi | 255 MPa / 37 ksi | 10 % | — |
Properties across the grain flow are lower, so forging design aligns grain flow with the principal stress in arms and links. Extruded 6151 bar has properties close to the forging values when heat-treated to T6.
Physical properties (typical)
- Density
- 2.70 g/cm³
- Modulus of elasticity
- about 69 GPa
- Thermal conductivity (T6)
- about 175 W/m·K
- Electrical conductivity (T6)
- about 45 % IACS
- Melting range
- about 590 – 650 °C
6151 forms and specification
Supply options
- Extruded forging stock and bar
- Round bar for slug cutting, typically 20 – 200 mm diameter
- Die forgings
- Closed-die parts to drawing, heat-treated to T6 and machined if required
- Profiles
- Simple solid sections in T6 for machined components, to drawing
- Length
- Mill lengths or cut slugs and blanks
- Standards
- ASTM B247, AMS 4125 (forgings); ASTM B221 for extruded bar; drawing-specific OEM specifications
Forging, heat treatment and machining
Heat treatment
Solution treatment around 510 – 525 °C, rapid water quench, then artificial ageing at about 165 – 175 °C for several hours to reach T6.
Machining
Machines well in T6, with short chips and a good finish using sharp carbide tooling.
Corrosion
Good resistance in road environments; anodising or painting adds protection in salt-spray zones.
Automotive uses of 6151
- Suspension links and knuckle components where intricate forged shapes are needed
- Steering and brake parts: brackets, levers and mounting arms
- Driveline and engine accessories: pulleys, brackets and housings machined from forgings
- Motorcycle and bicycle parts: clamps, yokes and cranks
For body structure and interior trim, extrusion alloys such as 6063, 6106 or 6005A are more suitable than 6151.
6151 compared with 6061 and 6082 forgings
| Property | 6151-T6 | 6061-T6 | 6082-T6 |
|---|---|---|---|
| Typical tensile strength | about 330 MPa | about 310 MPa | about 310 – 340 MPa |
| Die-fill in intricate forgings | Excellent | Good | Good |
| Main market | North American forgings | Global | Europe |
How to order 6151 from Metline
- SpecifyAlloy and temper (6151-T6), form (bar, slug, forging), drawing or size, quantity and annual volume.
- Confirm the standardASTM B247 or AMS 4125 for forgings, ASTM B221 for extruded bar, or your OEM specification.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectMaterial is cut, heat-treated as specified, inspected for dimensions and properties, and packed for export.
- Document and shipEach lot ships with an EN 10204 3.1 mill test certificate, lot traceability and a packing list, in seaworthy export packing. Third-party inspection can be arranged on request.
References and standards
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- SAE AMS 4125 – Aluminum Alloy Die Forgings and Rolled or Forged Rings, 6151-T6
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
6151 aluminium (aluminum): frequently asked questions
What is 6151 aluminium mainly used for?
Intricate closed-die forgings that need good die-fill, moderate strength and corrosion resistance, such as suspension, steering and accessory parts.
How strong is 6151-T6?
Typical tensile strength is about 330 MPa and yield about 295 MPa. ASTM B247 minimums for T6 die forgings are 303 MPa tensile and 255 MPa yield parallel to grain flow.
Is 6151 the same as 6061?
No. 6151 has more silicon, less magnesium, no required copper and more chromium. Strength is similar, but 6151 fills complex forging dies more easily.
Can 6151 be extruded into profiles?
Yes, mainly as round bar and simple solid sections for forging stock and machined parts; it is not a typical alloy for thin-wall hollow profiles.
Do you ship 6151 internationally?
Yes. Metline supplies 6151 bar and parts worldwide with EN 10204 3.1 certificates and export packing.
Need 6151 forging stock or parts?
Send the form, size or drawing, temper and quantity. We will reply with options, certification and delivered pricing.
