A metal strength chart is useful only when the numbers are read in the right context. “Strong” can refer to resistance to pulling, permanent bending, crushing, wear, impact, or repeated loading. A steel shaft, aluminum drone bracket, stainless steel housing, and titanium aerospace fitting may all require high performance, but not necessarily the same property. Yield strength may control whether a bracket permanently bends. Tensile strength may matter for a tension-loaded tie rod. Specific strength can drive lightweight design, while hardness can matter most for a wear surface. Density, stiffness, corrosion resistance, temperature, machinability, and cost complete the decision. The best material is therefore not simply the strongest metal in a list, but the alloy and condition that meets the part’s real failure risks and manufacturing constraints.
What Does a Metal Strength Chart Measure?
A metal strength chart normally compares tensile strength, yield strength, density, hardness, and sometimes elastic modulus. These terms describe different behaviors. Tensile strength of metals, also called ultimate tensile strength, is the maximum stress a specimen can withstand during a tensile test before fracture. It is often the value behind searches such as breaking strength of steel, steel ultimate strength, or steel tensile strength psi. For reference, 1 ksi is approximately 6.895 MPa. However, a part may become unusable before it reaches its breaking point because it has already yielded, distorted, cracked under fatigue, or lost alignment with mating components.
Tensile Strength and Breaking Strength of Steel
Steel tensile strength can range widely because “steel” includes low-carbon grades, alloy steels, tool steels, stainless steels, and heat-treated steels. Mild steel may have an ultimate tensile strength around 400–550 MPa, while quenched and tempered alloy steels can exceed 1,000 MPa. The tensile yield strength of steel is usually lower than its ultimate tensile strength. This gap reflects the difference between the onset of permanent deformation and final fracture. A tensile strength chart should therefore identify the alloy, form, and treatment condition rather than presenting one number for all steel. AISI 4140, for example, can show very different results when annealed, normalized, or oil-quenched and tempered.
Yield Strength, Hardness, Toughness, and Stiffness
Steel yield strength, yield stress of steel, and Fy of steel describe the stress at which permanent deformation begins. This is usually more important than fracture strength for structural brackets, frames, mounting plates, flanges, and housings that must keep their geometry during service. Hardness measures resistance to localized indentation or abrasion; it is not the same as strength. Toughness describes the ability to absorb energy before fracturing, while elastic modulus describes stiffness, or how much a material elastically deflects under load. A high hardness material can resist wear but still be vulnerable to brittle fracture or impact damage. This is why a metals hardness chart should be read alongside tensile, yield, and impact data rather than treated as a complete measure of metallic strength.
Metal Strength Chart: Common Metals and Alloys Compared
The metal strength chart below provides representative room-temperature values for common engineering materials. These are not universal design limits. Alloy grade, temper, heat treatment, section thickness, product form, direction of testing, and specification standard can all change the result. For example, the yield strength of aluminum depends strongly on temper, while copper strength changes substantially with cold work. Use these figures for early material screening, then confirm final values through the applicable standard, supplier certificate, and part-specific validation.
| Material | Typical Tensile Strength | Typical Yield Strength | Densidad | Módulo de elasticidad | Hardness Range | Resistencia a la corrosión | Aplicaciones típicas |
|---|---|---|---|---|---|---|---|
| Mild / low-carbon steel | 370–550 MPa | 235–300 MPa | 7.85 g/cm³ | ~200 GPa | 100–160 HB | Low without coating | Brackets, bases, welded structures |
| A36 structural steel | 400–550 MPa | ≥250 MPa | 7.85 g/cm³ | ~200 GPa | 120–160 HB | Low without coating | Plates, frames, fixtures |
| 4140 alloy steel, heat-treated range | 950–1,400 MPa | 650–1,170 MPa | 7.85 g/cm³ | 205 GPa | 28–42 HRC | Moderada | Shafts, gears, high-load pins |
| 4340 alloy steel, heat-treated range | 1,080–1,600 MPa | 930–1,400 MPa | 7.85 g/cm³ | 205 GPa | 30–45 HRC | Moderada | Aircraft fittings, heavy-duty shafts |
| 304 stainless steel, annealed | 505–750 MPa | 205–310 MPa | 8.00 g/cm³ | 193 GPa | 150–200 HB | Bueno | Food equipment, housings, fittings |
| 316 stainless steel, annealed | 515–620 MPa | 205–290 MPa | 8.00 g/cm³ | 193 GPa | 150–200 HB | Muy buena | Marine and chemical equipment |
| 6061-T6 aluminum | ~310 MPa | ~276 MPa | 2.70 g/cm³ | 68.9 GPa | ~95 HB | Bueno | Brackets, housings, fixtures |
| 7075-T6 aluminum | ~572 MPa | ~503 MPa | 2.81 g/cm³ | 71.7 GPa | ~150 HB | Fair to good | High-strength lightweight parts |
| Ti-6Al-4V titanium | 900–1,000 MPa | 830–900 MPa | 4.43 g/cm³ | ~114 GPa | 32–36 HRC | excelente | Aerospace, medical, performance parts |
| C110 copper | 210–350 MPa | 33–205 MPa | 8.93 g/cm³ | 110 GPa | 40–80 HB | Bueno | Busbars, heat-transfer parts |
| C360 brass | 338–470 MPa | 124–360 MPa | 8.50 g/cm³ | 97 GPa | 55–100 HB | Bueno | Precision-turned fittings |
| Inconel 718, precipitation hardened | 1,275–1,400 MPa | 1,030–1,100 MPa | 8.19 g/cm³ | ~200 GPa | 36–44 HRC | excelente | High-temperature aerospace parts |
Representative values above are drawn from material data for specific conditions, including 6061-T6, 7075-T6, Ti-6Al-4V, annealed 304/316 stainless steel, C360 brass, and precipitation-hardened Inconel 718.
Steel Strength: Why Steel Remains a Leading Structural Material
Steel strength remains the reference point for many structural and industrial designs because steel combines useful tensile strength, high stiffness, broad availability, and practical cost. When people ask “how strong is steel?” or search for the strongest steel, the answer depends on the steel family and condition. Mild steel is economical and weldable, but it is not selected for maximum hardness or wear resistance. Alloy steel can provide much higher strength after heat treatment. Tool steel can achieve high hardness for tooling and wear surfaces, though it may sacrifice toughness or machinability. Stainless steel provides corrosion resistance, but its strength is not automatically higher than that of alloy steel.
The strongest type of steel is not one fixed grade. For maximum tensile strength, selected high-strength alloy steels, maraging steels, and tool steels can outperform ordinary structural steel. For hot service, Grade 91 steel and ASTM A217 Grade C12A are designed around high-temperature strength and creep resistance rather than being direct replacements for room-temperature structural steels. Their minimum tensile strength, heat treatment, operating temperature, weld procedures, and code requirements must be checked against the relevant ASTM or ASME specification. A high tensile strength material is valuable only when its ductility, toughness, corrosion resistance, welding requirements, and machining route also match the design.
Is Aluminum Stronger Than Steel?
Steel is usually stronger and much stiffer than aluminum when comparing common grades on an absolute basis. It also deflects less under the same load because its elastic modulus is roughly three times higher than that of aluminum. However, aluminum is far lighter. This is why the question “is aluminum stronger than steel?” needs a more precise answer: steel generally wins in absolute strength and stiffness, while high-strength aluminum can be more attractive where low mass matters.
| Material | Resistencia a la tracción | Límite de fluencia | Densidad | Approx. Specific Tensile Strength | Módulo de elasticidad | Mecanizabilidad | Aplicaciones típicas de CNC |
|---|---|---|---|---|---|---|---|
| 6061-T6 aluminum | 310 MPa | 276 MPa | 2.70 g/cm³ | 115 | 68.9 GPa | excelente | Housings, brackets, fixtures |
| 7075-T6 aluminum | 572 MPa | 503 MPa | 2.81 g/cm³ | 204 | 71.7 GPa | Bueno | Lightweight high-load parts |
| Acero dulce | 400–550 MPa | 235–300 MPa | 7.85 g/cm³ | 51–70 | ~200 GPa | Bueno | Bases, brackets, welded parts |
| Acero aleado 4140 | ~1,140 MPa | ~965 MPa | 7.85 g/cm³ | 145 | 205 GPa | Fair | Shafts, gears, pins |
| Acero inoxidable 304 | ~505 MPa | ~215 MPa | 8.00 g/cm³ | 63 | 193 GPa | Fair | Corrosion-resistant housings |
| Ti-6Al-4V titanium | ~950 MPa | ~880 MPa | 4.43 g/cm³ | 214 | ~114 GPa | Desafiante | Aerospace and medical parts |
6061-T6 is commonly chosen for general CNC brackets, mounting plates, enclosures, and fixtures because it balances strength, corrosion resistance, availability, and machinability. 7075-T6 has substantially higher strength, but lower corrosion resistance and weaker welding suitability can limit its use. Titanium offers excellent strength-to-weight performance, yet its cost and machining difficulty are higher.
Specific Strength Formula and Strength-to-Weight Ratio
The specific strength formula is simple: specific strength = strength ÷ density. In preliminary screening, designers often divide tensile or yield strength by density to compare how much load-bearing capability a material provides per unit mass. This is why aluminum, titanium, magnesium alloys, and certain high-strength steels can all be attractive for lightweight assemblies. A material with lower absolute strength can still be a better choice when mass reduction is critical.
For example, 7075-T6 aluminum has much lower absolute stiffness than steel, but its low density gives it a strong strength-to-weight ratio. Ti-6Al-4V combines high tensile strength with a density of about 4.43 g/cm³, making it especially relevant in aerospace, motorsport, medical, and compact robotics components. High-specific-strength steel also has a place where stiffness, durability, cost, and machining reliability are more important than minimum mass. For Alloy 2319 aluminum, specific strength must be evaluated by the exact product form and temper; it should not be treated as one universal value. Strength-to-weight calculations are useful screening tools, but they do not replace buckling analysis, deflection checks, fatigue testing, or design safety factors.
Metal Density Chart: Heavy Metals vs Lightweight Metals
Density and strength are separate properties. A heavy metal may be dense without being the best structural choice, while a lightweight alloy may provide better performance in a mass-sensitive design. Copper is heavier than steel by density, and platinum is much denser than steel, but neither fact proves that they are stronger in every loading condition. The heaviest metals list is therefore useful for weight calculations, radiation shielding, balance weights, and thermal applications, not as a ranking of engineering strength.
| Metal or Alloy | Typical Density | Relative Weight | Typical Strength Category | Common Applications |
|---|---|---|---|---|
| Magnesio | 1.74 g/cm³ | Very light | Bajo a medio | Lightweight housings, mobility parts |
| Aluminum alloy | 2.70–2.81 g/cm³ | Ligero | Medio a alto | Frames, housings, brackets |
| Aleación de titanio | 4.43 g/cm³ | Medium-light | Alto | Aerospace, medical, chemical service |
| Acero al carbono / aleado | 7.85 g/cm³ | Medium-heavy | Medium to very high | Structures, gears, shafts |
| Acero inoxidable | ~8.00 g/cm³ | Medium-heavy | Medio a alto | Corrosion-resistant parts |
| Latón | ~8.50 g/cm³ | Pesado | Medio | Fittings, turned components |
| Cobre | 8.93 g/cm³ | Pesado | Bajo a medio | Electrical and thermal parts |
| Inconel 718 | 8.19 g/cm³ | Pesado | Muy alto | High-temperature components |
| Lead | 11.34 g/cm³ | Very heavy | Low structural strength | Shielding, ballast |
| Tungsten | ~19.3 g/cm³ | Extremely heavy | High hardness, application-dependent toughness | Counterweights, high-temperature tools |
| Platinum | 21.45 g/cm³ | Extremely heavy | Application-dependent | Catalysis, electrodes, specialty uses |
Lead, tungsten, and platinum are all much denser than common structural metals. Tungsten has a density near 19.3 g/cm³, while platinum is about 21.45 g/cm³; density alone should never be interpreted as tensile strength or impact resistance.
Metal Hardness vs Strength for Wear and Machining
A metals hardness chart is particularly useful when a part faces abrasion, sliding contact, indentation, or repeated surface loading. Hardened alloy steel and tool steel are often selected for dies, punch components, gear teeth, wear pads, and bearing-contact surfaces because they can retain hardness under load. However, high hardness generally increases cutting forces, reduces tool life, and makes final machining more difficult. Heat-treated steel may require carbide tooling, rigid workholding, controlled coolant, slower finishing operations, and sometimes grinding after machining.
Stainless steel can work-harden during cutting, so poor tool engagement can create heat and rapidly damage cutting edges. Titanium has high strength and low thermal conductivity, which concentrates heat near the cutting zone and requires conservative machining strategy. Aluminum is much easier to mill and drill, while brass is a highly practical material for precision turning because it machines cleanly and has excellent chip control. C110 copper offers excellent electrical and thermal conductivity, but it is softer and can be less efficient to machine than free-cutting brass. Hardness should therefore be selected for its functional purpose, not simply because a hard material sounds like a stronger one.
How to Choose High-Strength Metals for CNC Machining
Load Type and Failure Mode
Start by defining whether the part sees tension, bending, compression, shear, impact, or repeated fatigue loading. A threaded rod may be governed by tensile and fatigue strength. A pin may be governed by shear strength. A thin housing may be controlled by stiffness and local bending rather than ultimate tensile strength. Shafts, gears, suspension components, and robotic arms also need attention to cyclic stress, surface finish, and stress concentration around keyways, grooves, threads, and sharp transitions.
Geometry, Surface Condition, and Environment
Sharp internal corners, deep pockets, holes near edges, thin walls, and abrupt section changes can raise local stress beyond the average calculated value. Surface scratches, machining marks, corrosion pits, and unrelieved residual stress can reduce fatigue life. In wet, marine, chemical, or high-temperature service, material selection should also account for corrosion resistance, galvanic compatibility, oxidation, and thermal stability. Stainless steel, titanium, aluminum, carbon steel, and nickel alloys may all be suitable, but for different environments and different budgets.
Manufacturing Cost and Process Route
Material choice affects more than strength. It also changes tool wear, cycle time, fixturing, inspection, available stock, surface finishing, and delivery time. A material with high tensile strength may need special machining steps or post-machining heat treatment. For complex prismatic parts, Servicios de fresado CNC can support pockets, side holes, ribs, contours, and mounting faces. Cylindrical shafts, collars, bushings, threads, and grooves may be better suited to Servicios de torneado CNC. The final choice should balance part performance with total manufacturing risk.
Common Mistakes When Comparing Metal Strength
The first mistake is comparing annealed, cold-worked, and heat-treated materials as though they were identical. The second is treating hardness as tensile strength. The third is ignoring yield strength even when the part must maintain accurate shape and alignment. The fourth is overlooking fatigue: a component can fail under repeated stress far below its listed ultimate strength. The fifth is ignoring density and stiffness when deflection or vibration matters. The sixth is selecting the highest-strength alloy without checking corrosion resistance, galvanic contact, or operating temperature.
Another common mistake is using generic web values as final design data. Material charts are helpful for screening, but design release should use the material grade, temper, section size, applicable specification, supplier certificate, and engineering validation plan. It is also misleading to compare metal with non-metal examples such as diamond, silk, or carbon fiber as though all properties are directly equivalent. Material selection should remain focused on the real design requirement: strength, stiffness, wear, conductivity, corrosion resistance, weight, cost, or manufacturability.
How Tuofa CNC Germany Helps Match Material Strength to Part Performance
tuofa cnc germany can support material selection as part of a practical manufacturing review for custom parts. When a customer submits 2D drawings or 3D models, the review can consider the intended load path, wall thickness, thin features, deep holes, threads, undercuts, slots, critical tolerances, and required surface condition. Material selection is then evaluated together with the manufacturing route instead of being treated as a separate purchasing decision.
For example, Servicios de mecanizado CNC can support early feasibility checks for parts that need a balance between strength and production cost. Aluminum CNC machining may fit lightweight housings and brackets, while stainless steel CNC machining can be better for corrosion-resistant parts. For compact, high-strength components, titanium CNC machining may be appropriate. Surface expectations should also be planned early because surface finishing services can affect appearance, corrosion protection, dimensions, and thread masking requirements.
Conclusión
A useful metal strength chart does not identify one universally strongest metal. It helps engineers compare the properties that matter for a defined part and service condition. Steel strength is valuable when high stiffness, broad availability, and cost efficiency are priorities. Aluminum is often the better choice where weight reduction and easy CNC machining matter. Titanium offers excellent specific strength and corrosion resistance, while stainless steel and nickel alloys can be preferable in corrosive or elevated-temperature environments.
The strongest metals are not always the best engineering materials. The correct decision depends on tensile strength, yield strength, hardness, toughness, density, stiffness, fatigue resistance, corrosion resistance, machining behavior, and overall cost. Use metal strength comparison tables for early screening, then validate the final choice with certified data, engineering analysis, prototypes, and real application requirements.
Preguntas Frecuentes
What metal is stronger than steel?
Some titanium alloys, nickel superalloys, tool steels, and heat-treated alloy steels can exceed ordinary carbon steel in selected strength measures. However, steel is a broad category, so the comparison must specify the exact grade, heat treatment, temperature, and loading condition.
Is aluminum stronger than steel?
Steel is usually stronger and stiffer in absolute terms. Aluminum is much lighter, and high-strength grades such as 7075-T6 can provide an excellent strength-to-weight ratio for lightweight structures, aerospace components, and performance parts.
What is the strongest type of steel?
There is no single strongest steel for every application. High-strength alloy steels, maraging steels, hardened tool steels, and specialized stainless steels can each lead in different areas such as tensile strength, hardness, corrosion resistance, or high-temperature performance.
What is the specific strength formula for metals?
Specific strength is commonly calculated as strength divided by density. It is useful for comparing lightweight materials, but the chosen strength value must be clearly defined as tensile strength, yield strength, or another relevant property under a stated material condition.