In today’s manufacturing industry, CNC machining technology is crucial, and the selection of metal materials is the key to the success of machining projects. Hard metals and soft metals have different properties and have their own advantages and disadvantages in different application scenarios. Understanding their characteristics, differences, and selection methods is of great significance to your CNC machining projects . Next, I will take you to an in-depth understanding of these two types of metals so that you can make wise decisions in practical applications.
What Are Hard Metals And Soft Metals
First of all, we need to clarify the essential difference between hard metal and soft metal. It is not just the surface feature of hardness, but also the level of microstructure and chemical composition. Hard metal atoms are tightly arranged, with strong bonding force, high hardness, high strength and wear resistance , while soft metal atoms are relatively loosely arranged, which makes them outstanding in ductility and plasticity. This inherent difference lays the foundation for their different performances in CNC machining .
Hard Metals Generally Refer To Materials With High Hardness, Strength And Wear Resistance :
Tungsten Steel : The main component is tungsten carbide WC, containing a small amount of cobalt Co as a binder, and the hardness can reach 89-94HRA), cobalt-chromium alloy : the cobalt content is about 60%-65%, the chromium content is about 25%-30%, and it also contains molybdenum, nickel and other elements, with good wear resistance and corrosion resistance .
Tool Steel : It has a high carbon content and also contains alloy elements such as tungsten, molybdenum, chromium, and vanadium, which can improve hardness and wear resistance .
Stainless Steel : Contains elements such as chromium and nickel. The chromium content is generally above 10.5%, which can form a dense oxide film and improve corrosion resistance .
Titanium Alloy : The main component is titanium Ti, and it also contains alloy elements such as aluminum and vanadium. For example, Ti-6Al-4V is a common titanium alloy with high strength, low density and good corrosion resistance .
These metals we are familiar with are often used to manufacture components that withstand high pressure and high wear environments, such as cutting tools (the tool life of carbide tools is 3-5 times longer than that of ordinary high-speed steel tools when cutting steel), molds (injection molds made of hard metal can withstand hundreds of thousands or even millions of injection cycles), and aircraft engine parts (titanium alloys are used for engine blades and can work reliably under high temperature and high pressure).
Soft Materials Usually Refer To Materials With Lower Metal Hardness, Better Ductility And Plasticity :
Aluminium : Aluminum with high purity has an elongation of 20% – 40% and a density of about 2.7g/cm³. It is a light metal .
Cuivre : The electrical conductivity is as high as 5.96×10⁷ S/m, and the thermal conductivity is about 401W/(m·K), which has good electrical and thermal conductivity .
Brass : Copper-zinc alloy, the zinc content is generally between 10% – 40%, with good machinability and corrosion resistance) etc.
Soft metals are widely used in electronic product casings (such as aluminum alloy mobile phone casings, which are light and easy to process), automotive heat dissipation components (copper radiators can quickly dissipate heat to ensure the normal operating temperature of the engine) and decorative parts (such as brass ornaments, which have a good appearance and texture).
Principal Features Of Hard Metal
Hard metals are widely used in industrial manufacturing and high-tech fields due to their excellent mechanical properties, wear resistance, fatigue strength and thermal properties. These characteristics make hard metals an ideal choice for cutting tools, mold manufacturing and aerospace.
Mechanical Properties
Most people know that hard metals are very strong and hard , and can withstand great pressure and friction. Let’s take tungsten steel as an example. Its hardness can be as high as 89-94HRA, which is much higher than ordinary metals. This is due to the compact crystal structure and alloy element strengthening, such as the high hardness of tungsten carbide particles and the cobalt binder that tightly binds them, making the overall performance excellent.
In the manufacturing of precision molds, we use hard metals to ensure the long-term shape and size stability of the molds . For example, the use of carbide inserts in automobile cover stamping molds can increase the mold life from hundreds of thousands of times to millions of times, effectively ensuring processing accuracy and surface quality.
Wear Resistance And Fatigue Performance
Hard metal has excellent wear resistance and performs well in high-wear environments. When cutting metal, using hard metal tools can effectively resist wear and reduce the frequency of replacement. At the same time, it has high fatigue strength and can withstand repeated loading and unloading cycles without cracking or breaking.
I have read a study that shows that under the same fatigue test, the fatigue life of carbide tools is several times higher than that of ordinary high-speed steel tools. For example, engine crankshafts (commonly made of alloy steel, surface quenching and other treatments to improve hardness and wear resistance) and gears (carburizing and quenching are used to improve surface hardness and fatigue strength) are subjected to alternating loads for a long time, so the high fatigue strength of hard metal is crucial.
Thermal Properties
Hard metals are generally resistant to high temperatures and have stable mechanical properties at high temperatures.
I remember that the melting point of titanium alloy can be as high as 1668°C, and it has good high-temperature strength and hardness. In the field of aerospace, the turbine blades of aircraft engines are made of titanium alloy, which can work reliably in harsh environments of high temperature and high pressure. Its thermal expansion coefficient is relatively small (about 8.6×10⁻⁶/°C for titanium alloy), and its size changes little when the temperature changes, which is conducive to ensuring the processing accuracy and component matching accuracy.
Applications typiques
In the field of cutting tools, carbide tools can efficiently cut various metal materials due to their high hardness and wear resistance. If we need to process ordinary carbon steel, it is recommended to use carbide tools , which can increase the cutting speed by 2-5 times compared with high-speed steel tools, thus improving processing efficiency and quality.
In mold manufacturing, hard metals can be used in injection molds, die-casting molds, etc. to withstand high-pressure impact and friction of plastic or metal melts.
In the aerospace field, for example, titanium alloys can be used to manufacture engine components, fuselage structural parts, etc., meeting the requirements of high strength, high temperature resistance, and lightweight. I remember that the Boeing 787 passenger aircraft uses a large amount of titanium alloys to reduce the structural weight .
Principal Characteristics Of Soft Metal
Soft metals are well-known for their superior machinability, electrical and thermal conductivity, and good mechanical properties, and are widely used in the fields of electronics, electrical and structural manufacturing. These characteristics make soft metals the preferred material for electrical components, radiators, building materials, and some lightweight equipment, and can meet the needs of high-efficiency processing and stable performance.
Mechanical Properties
Although soft metals have low hardness, they have good ductility and toughness. Let’s take aluminum as an example. Its elongation can reach 20% – 40%. It can be extruded into aluminum profiles for use in building doors and windows (broken bridge aluminum doors and windows use aluminum alloy profiles, which are light, corrosion-resistant, and strong enough to meet building requirements), automobile frames (aluminum alloy body frames can reduce the weight of the entire vehicle, improve handling performance and fuel economy) and other fields.
The toughness of soft metal makes it difficult to break when impacted and can absorb energy. For example, car bumpers are made of aluminum alloy, which can effectively cushion collisions and protect the safety of vehicles and passengers.
Machinability
In my opinion, soft metals have good machinability and are very convenient for cutting, forging, stamping and other processes. They have low hardness and small cutting force, so higher cutting speeds and feed rates can be used to improve processing efficiency.
For example, in the manufacture of electronic products, we can often see parts such as housings and circuit boards made of aluminum and copper. Mobile phone housings made of aluminum alloy can be quickly manufactured into complex shapes through precision CNC machining, with easy-to-control surface quality, reduced production costs and processing difficulty, and 30% – 50% higher production efficiency than machining hard metal housings.
Electrical And Thermal Conductivity
Many soft metals have good electrical and thermal conductivity. The copper we are familiar with is an excellent conductive metal with an electrical conductivity of up to 5.96×10⁷ S/m. It is widely used in wires and cables (in power transmission, copper cables have good conductivity and can reduce power loss), electronic components (such as the conductive lines of printed circuit boards), and other fields.
Not only copper, aluminum also has excellent thermal conductivity , with a thermal conductivity of about 237W/(m·K). It is often used to manufacture heat sinks (computer CPU heat sinks are made of aluminum alloy materials, which can quickly dissipate heat and ensure that the CPU is within the normal operating temperature range) and other heat dissipation components.
Applications typiques
In the automotive industry, aluminum alloys are used extensively to manufacture engine blocks (aluminum alloy blocks are about 30% lighter than cast iron blocks and have better heat dissipation performance), wheels (aluminum alloy wheels are beautiful, lightweight, and meet strength requirements), and other components to reduce the weight of the car and meet strength and thermal conductivity requirements.
In the field of consumer electronics, aluminum and magnesium alloys are often used to manufacture the casings of mobile phones, laptops and other devices. For example, the casing of Apple laptops is made of aluminum alloy, which not only has a good appearance and texture, but also can shield electromagnetic interference. Its machinability enables it to produce stylish and lightweight product designs.
In the construction field, aluminum alloy doors and windows are light, corrosion-resistant, and beautiful, which improve the energy-saving effect and overall quality of buildings. For example, modern high-rise buildings widely use thermally insulated aluminum doors and windows, which effectively reduce building energy consumption.
Comparative Analysis Of Hard Metal And Soft Metal
There are obvious differences between hard metals and soft metals in terms of hardness, strength, processing performance, cost and application scenarios. Hard metals are known for their high hardness and high strength, and are suitable for extreme environments and high-precision applications, but the processing cost is high. Soft metals have excellent processability and cost advantages, and are suitable for large-scale industrial production.
By comparing, we can help us choose materials more scientifically to meet the needs of different application scenarios :
Dureté And Strength Comparison
The hardness and strength of hard metals are significantly higher than those of soft metals. We have tested and found that the hardness of cemented carbide can reach 80-94HRA, while the hardness of ordinary aluminum alloys is usually between 30-100HB. This difference makes hard metal perform well in high-pressure and high-wear environments . This allows it to cut high-hardness workpiece materials in metal cutting .
Soft metals are prone to wear and damage. However, soft metals have better toughness, can absorb more energy when impacted, and are not prone to brittle fracture. For example, aluminum can have an elongation of 20% – 40%. This elongation reflects the toughness of aluminum during stretching, indicating that aluminum can deform to a certain extent without breaking. In some occasions that require high impact toughness (such as anti-seismic components), soft metals have advantages.
Processing Performance Comparison
Generally speaking, hard metal processing is difficult and requires special tools and processes. Because of its high hardness, high heat during cutting, rapid tool wear, low cutting speed and feed rate, and effective cooling and lubrication system are required. For example, when processing titanium alloy, the cutting speed is usually 50% – 80% lower than that of processing soft metals, and titanium-containing tool coatings (such as TiN coatings) are required to increase tool life.
Soft metals have good processing performance, can use high cutting parameters, and have high processing efficiency, but they are prone to problems such as chip entanglement and difficult to control surface roughness. For example, when we process aluminum alloys, chips are easy to entangle the tool, which can be solved by optimizing the tool geometry (using a large rake angle, sharp cutting edge) and using chip breakers.
Cost And Application Scenarios
they are irreplaceable in high-end and critical application fields , such as aerospace, high-end mold manufacturing, etc. Soft metals are low-cost and economical to process, and are widely used in large-scale production fields that are not particularly demanding on performance and are cost-sensitive , such as automotive parts and consumer electronics housings.
We all know that when a car is manufactured, its engine will be composed of key pistons, crankshafts and other hard alloy or high-strength alloy steel components , while non-critical brackets, housings and other components will use soft metals such as aluminum alloys. For example , the use of aluminum alloy brackets and housings can reduce costs by about 20% – 30% compared to steel , thereby reducing costs while meeting performance requirements .
Comment To Choose Til Right Metal For CNC Machining
Choosing metals suitable for CNC machining requires comprehensive consideration of application scenario requirements, cost and efficiency, processing equipment and technical requirements, etc. Hard metals are suitable for high-performance fields due to their excellent wear resistance and strength, while soft metals are suitable for mass production applications due to their good machinability and cost advantages.
The following is a table I made to help you analyze how to scientifically select metal materials from multiple aspects :
| Factor | Hard Metal | Soft Metal |
| Application scenario requirements | – Suitable for high temperature, high pressure and high wear environment. – Examples: aircraft engine blades (titanium alloy), industrial cutting tools (cemented carbide). | – Suitable for scenes with complex shapes, light weight but low strength requirements. – Examples: electronic housing (aluminum alloy), automotive interior parts (magnesium alloy). |
| Material Cost | 5-10 times that of ordinary aluminum alloy . | 50%-70% cheaper than hard metals . |
| Processing Cost | – High tool cost: Carbide tools are 2-3 times more expensive than high-speed steel tools. – Long processing time: The processing time is 2-3 times that of soft metals . | – High processing speed: cutting speed up to 1000-3000 m/min . – Reduce production cost by about 15%-25% and shorten production cycle. |
| Mechanical Properties | – High hardness and strength: The hardness of cemented carbide reaches 80-94HRA , suitable for high loads and harsh conditions. | – Better toughness: For example, the elongation of aluminum alloy can reach 20%-40% , which is suitable for scenarios with high requirements for impact toughness. |
| Wear Resistance And Fatigue Performance | – Excellent wear resistance, suitable for long-term use in high friction conditions, such as engine crankshafts and gear parts. | – Less wear resistance, but performs well in scenarios where stress is not frequent. |
| Processing Difficulty | – Difficult cutting: low cutting speed and efficient cooling system are required (coolant pressure can reach 10-20 MPa ). | – Excellent processing performance: It can be completed using ordinary CNC machine tools, but the tool design needs to be optimized to reduce the chip entanglement problem. |
| Equipment Requirements | – High-end equipment: high-speed cutting machine tools (spindle speed 20,000 rpm ), and high-performance tools such as diamond-coated tools are required. | – Ordinary CNC machine tools can meet the processing requirements, and the equipment cost is relatively low. |
| Typical Application Scenarios | – Aerospace: such as titanium alloys for turbine blades and fuselage structures. – High-end molds: such as cemented carbide molds. | – Consumer electronics: such as aluminum alloy housings. – Automobiles: such as aluminum alloy brackets and magnesium alloy parts to reduce weight and costs. |
| Processing Efficiency | – Long processing time, suitable for high value-added, small batch production. | – Fast processing speed, suitable for large-scale batch production, improving efficiency and reducing costs. |
| Economical | – Long-term economical: high-performance applications in high-end fields can offset high costs and are suitable for critical components and high-precision requirements. | – Short-term economic efficiency: low cost, high efficiency, suitable for scenarios with low performance requirements, and widely used in the production of general mechanical parts. |
FAQ
Is Gold A hard Or Soft Metal?
Gold is a soft metal. I remember that its Brinell hardness is only about 25 HB , which is softer than most metals. The gold jewelry we often see is easily scratched because the hardness of pure gold is very low. However, gold has very good ductility. For example, 1 gram of gold can be stretched into a 3,000-meter-long gold wire or hammered into a 1-square-meter gold foil.
Is Silver A Hard Or Soft Metal?
Silver is a soft metal with a Brinell hardness of about 24 HB , which is similar to gold, but slightly harder. Pure silver is also easily scratched and may wear out over time. However, silver is also very ductile. For example, 1 gram of silver can be stretched into more than 2,000 meters of silver wire .
Ce qu'il faut faire Is Til Hardest Metal In Til World?
The hardest metal in the world is chromium. Its Mohs hardness is as high as 8.5 and its Brinell hardness is 700 HB , which is much higher than ordinary metals. I once read that chromium can still maintain extremely high hardness under high temperature conditions, so it is widely used in the manufacture of cutting tools and wear-resistant coatings .
Is Titanium A Hard Or Soft Metal?
Titanium is a hard metal, but it has a good balance between hardness and toughness. The Brinell hardness of titanium is usually between 200-400 HB , and the tensile strength of titanium alloys, such as the commonly used Ti-6Al-4V, can reach 950 MPa .
Ce qu'il faut faire Is Til Softest Metal In Til World?
The softest metal in the world is cesium. Its Brinell hardness is only 0.2 HB , and it can be scratched with a fingernail. The melting point of cesium is also very low, about 28.5°C , and it will become liquid at a slightly higher room temperature in the summer. I remember that cesium is very chemically active and will react violently immediately when it comes into contact with water. Although this metal is soft, its application is irreplaceable in some high-tech fields, such as atomic clocks.
Ce qu'il faut faire Is Til Différence Bentre Hard Copper And Soft Copper?
The difference between hard copper and soft copper lies in their processing methods and usage scenarios. Hard copper has not been annealed, has high strength, and its tensile strength can reach more than 200 MPa , which is suitable for use in places where high strength is required. After annealing, the ductility of soft copper is significantly improved, and the elongation can reach 40%-50% , which is more suitable for use in places that require bending and forming. I personally prefer to use soft copper to make parts with complex shapes, which is easier to process.
If Til Hardeur Of A Metal Increases, What Happens To Its Brittleness?
Increased hardness usually means increased brittleness. I remember once processing high carbon steel. After hardening, the hardness was as high as 60 HRC , but it broke easily when impacted. The reason is simple. The hardening process restricts the movement of crystal dislocations inside the material, and the plastic deformation capacity is greatly reduced.
Conclusion
Hard metal and soft metal have their own characteristics in CNC processing. Hard metal is suitable for high precision and extreme environments due to its high strength, wear resistance and high temperature resistance, while soft metal is more suitable for large-scale production and lightweight design due to its good machinability and low cost. In actual selection, we need to choose according to comprehensive factors such as specific application scenarios, processing efficiency and economy to help our projects be successfully completed.