Density of brass: values, influencing factors, applications and measurement methods
The density of brass is one of the important indicators for evaluating its performance and application value. As an alloy material widely used in electronics, electrical, mechanical processing and other fields, brass is widely used due to its corrosion resistance, strong conductivity and easy processing.
In precision CNC machining, mastering the density of brass not only helps to control the weight of parts, but also to grasp the performance and quality of brass parts.
We focus on high-precision metal processing, deeply understand the characteristics of various materials, and ensure that every product has both quality and reliability. This article will give you a comprehensive understanding of the density of brass and its value in engineering applications.
1.What is brass?
Brass is an alloy material composed of copper and zinc. According to different uses and needs, the ratio of copper and zinc in brass can be adjusted to change its physical and chemical properties. The simplest brass is a copper-zinc binary alloy, called simple brass or ordinary brass. By changing the ratio of copper and zinc, brass materials with different properties and uses can be obtained.
2.Definition and range of brass density
Brass is an alloy composed of copper and zinc, and sometimes contains other elements such as lead, tin, manganese, iron and nickel to form special brass. Generally speaking, the density of brass ranges from 8.40 to 8.80 g/cm3, which is between the density of pure copper (8.92 g/cm3) and pure zinc (7.14 g/cm3). It is worth noting that the density of brass is not fixed, but is affected by many factors such as its composition ratio and manufacturing process.
Below is a table comparing the density of brass to other common metals, all in g/cm³ (grams per cubic centimeter):
| Metal Name | Density (g/cm³) | Remarks |
| Brass | 8.4 – 8.8 | Copper-zinc alloy; density varies slightly with composition |
| Pure Copper | 8.92 | High density, excellent electrical conductivity |
| Aluminum | 2.70 | Lightweight, commonly used in aviation and lightweight structures |
| Zinc | 7.14 | One of the important alloying elements in brass |
| Iron | 7.87 | Basic industrial metal |
| Stainless Steel | 7.75 – 8.05 | Specific density depends on the grade |
| Carbon Steel | 7.85 | Often used in structural components |
| Lead | 11.34 | High density, used for shielding, shock absorption, etc. |
| Silver | 10.49 | Precious metal, extremely high electrical conductivity |
| Gold | 19.32 | Extremely high density, easy to identify, precious metal |
| Nickel | 8.90 | Strong corrosion resistance, commonly used in alloys |
| Titanium | 4.51 | Lightweight and high strength, widely used in aviation and medical fields |
| Magnesium | 1.74 | One of the lightest metals, flammable |
| Tin | 7.31 | Commonly used in solders |
| Chromium | 7.19 | Often used in electroplating, strong corrosion resistance |
| Manganese | 7.21 | Added to steel to increase hardness |
| Tungsten | 19.25 | Density almost the same as gold, used in high-temperature alloys |
| Molybdenum | 10.22 | High melting point metal, used in heat-resistant alloys |
| Cobalt | 8.90 | High-temperature alloy material, common in batteries |
| Beryllium | 1.85 | Ultra-light, commonly used in aerospace and nuclear industries |
3.Why understanding the density of brass is crucial for manufacturing and engineering applications
(1) Material selection:
The density of brass affects its applicability in different applications. Understanding density helps engineers and manufacturers select the right material to meet the needs of a specific project.
(2) Design calculations:
When designing structures and manufacturing mechanical components, accurate density data is a key parameter for weight, strength, and stability calculations.
(3) Cost control:
Density is directly related to the weight of the material, which in turn affects transportation and manufacturing costs. By understanding the density of brass, manufacturers can more accurately estimate material costs.
(4) Planning usage scenarios:
The density of brass is closely related to its physical and mechanical properties (such as wear resistance, strength, etc.). Understanding these properties can help predict how the material will perform in different environments.
(5) Quality testing:
During the manufacturing process, density can be measured to detect the purity and consistency of the material and ensure that the product quality meets the standards.
4.Classification and density of common brass
(1) Ordinary brass:
It is composed of copper and zinc, and its density varies with the zinc content. Common brass such as H68 brass (68% copper and 32% zinc) has a density of about 8.5 g/cm³, has good plasticity and hot and cold processing properties, and is widely used in electrical components, decorations, etc.
(2) Lead brass:
Lead is added to improve cutting performance, and the density is slightly lower. For example, HPb59-1 (59% copper and 1% lead) has a density of about 8.3 g/cm³ and is often used to make watch parts and bearings, etc.
Cast mechanical properties and machinability of typical SeBiLOY series brasses and lead brasses:
| Material | Tensile Strength/MPa | Yield Strength/MPa | Elongation/% | Relative Machinability/% |
| C89510 Bismuth – Selenium Brass | 209 | 136 | 12 | 75 |
| C83600 Lead Brass | 255 | 117 | 30 | 84 |
| C89520 Bismuth – Selenium Brass | 215 | 145 | 10 | 85 |
| C84400 Lead Brass | 241 | 47 | 28 | 90 |
| C89550 Bismuth – Selenium Brass | 332 | 200 | 8 | 75 |
| C85800 Lead Brass | 332 | 192 | 9 | 80 |
(3) Tin brass:
Tin is added to improve corrosion resistance, especially seawater corrosion resistance, and is called “naval brass”. For example, HSn70-1 has a density of about 8.45 g/cm³ and is often used in the manufacture of ships and marine equipment.
(4) Manganese brass:
Manganese is added to improve strength and corrosion resistance. For example, HMn58-2 has a density of about 8.5 g/cm³, is suitable for hot and cold pressure processing, and is widely used in the manufacture of high-strength structural parts.
(5) Aluminum brass:
Aluminum-containing brass has high strength and wear resistance, such as HAl77-2, which has a density of about 8.6 g/cm³ and is often used to manufacture durable mechanical parts and bearings.
The density of brass varies slightly due to its different component ratios, giving it unique performance advantages in different industrial applications.
5.Factors affecting the density of brass
(1) Component ratio
The main components of brass are copper and zinc, and the ratio of the two directly affects the density of brass. When the copper content is high, the density of brass is close to that of pure copper; conversely, when the zinc content is high, the density of brass is close to that of pure zinc.
For example, the density of H62 brass (62% copper, 38% zinc) is about 8.60 g/cm3, while the density of H70 brass (70% copper, 30% zinc) is slightly higher, about 8.70 g/cm3.
(2) Alloying elements
In addition to copper and zinc, other alloying elements such as lead, tin, manganese, iron and nickel may be added to brass, and the addition of these elements will further change the density of brass.
For example, the density of lead brass may be slightly lower than that of ordinary brass because the density of lead is lower (11.34 g/cm3), but its addition can improve the cutting performance of brass.
(3) Manufacturing process
The manufacturing process of brass will also affect its density. The density of cast brass and machined brass may be different.
Cast brass may form some pores during the cooling process, resulting in a slightly lower density than processed brass. Processed brass has a denser internal structure through rolling, extrusion and other processes, so its density is relatively high.
6.Relationship between brass density and performance
(1) Density and mechanical properties
The density of brass is usually between 8.4-8.8 g/cm3, and its mechanical properties such as tensile strength and yield strength are affected by density.
For example, brass alloys with higher density usually have higher strength and hardness due to their denser internal structure, but may have slightly worse ductility.
Moderately dense brass such as HMn57-3-1 (density of about 8.4 g/cm³) has good ductility while maintaining good strength, and is suitable for manufacturing parts that require a certain strength and plasticity.
As the zinc content in simple brass increases, the strength and hardness of brass continue to increase, while the density, electrical conductivity and thermal conductivity continue to decrease. Single-phase α brass has good processing properties, and its plasticity increases with the increase of zinc content, reaching a maximum value before the appearance of β’ phase.
(2) Density and physical properties
Density also affects the physical properties of brass, such as electrical conductivity and thermal conductivity. A denser brass structure usually has better electrical conductivity and thermal conductivity because a more compact atomic arrangement helps electrons and heat energy to be transferred more efficiently.
However, as the temperature rises, the density of brass decreases due to thermal expansion and contraction, which may slightly affect its electrical and thermal conductivity.
(3) Density and corrosion resistance
The density of brass has a certain effect on its corrosion resistance. Brass with higher density, due to its denser structure, can more effectively prevent the penetration of corrosive media, thereby improving corrosion resistance.
For example, in marine or chemical environments, brass alloys with higher density can exhibit better corrosion resistance, which is related to its compact structure and can effectively resist the erosion of corrosive media such as chloride ions.
7.Several methods for measuring the density of brass
(1) Archimedean principle method:
By measuring the difference between the weight of the brass sample in air and the weight when completely immersed in water, the weight of the water displaced by the sample is calculated, and then its volume is obtained. Finally, the density is calculated using the following formula: density = mass/displaced volume.
(2) Densitometer method:
Using a densitometer specially designed to measure the density of liquids, the brass sample is processed into a regular shape and then placed in the container, and the density value is directly read. This method is simple and fast and suitable for rapid measurement.
(3) Pycnometer method:
Using a pycnometer with a known volume, the weight of the empty bottle, the total weight after being filled with water, and the total weight of the brass sample placed in the bottle and filled with water are measured respectively, and the weight of the water displaced by the brass sample is calculated, so as to obtain its volume and calculate the density.
(4) Displacement method:
Record the initial water level in a container filled with water, record the height of the water level rise after placing the fully submerged brass sample, calculate the volume of the sample after the water level rises, and combine the mass to calculate the density.
8.Application considerations of brass density
(1) Select brass type according to application
In different application fields, it is crucial to select the right type of brass. Ordinary brass is mainly used to manufacture valves, water pipes, etc. Its density is moderate and can meet the requirements of general mechanical properties. In situations where higher strength and corrosion resistance are required, such as shipbuilding and chemical equipment, special brass will be selected, and its density may vary due to the addition of other elements.
(2) The influence of density on processing technology
The density of brass also has a significant impact on its processing technology, such as casting, forging and machining. Brass with higher density has poor fluidity during casting and requires higher casting temperature and pressure. Brass with lower density has better fluidity, but may affect its mechanical strength.
In addition, during machining, differences in density will also affect cutting force and tool wear. Therefore, understanding the density of brass can help optimize the processing technology and improve production efficiency and product quality.
(3) The use of brass in other fields
Brass is also widely used in electronics, electrical and electronic, architectural decoration and musical instrument manufacturing due to its good mechanical properties and beautiful appearance. In these applications, the density and color of brass are important considerations when selecting materials.
For example, in the electrical and electronic industries, high copper content brass with good conductivity should be given priority; in musical instrument manufacturing, brass of a specific density can affect the tone and sound quality of the instrument.
9.Summary
In summary, the density of brass, as one of its basic physical properties, has an important impact on its performance and application. By deeply studying the definition, influencing factors, measurement methods and application considerations of brass density, more comprehensive and in-depth support can be provided for the research and production application of brass materials.
FAQs:
What is the density of brass?
The density is about 8.4–8.8g/cm³, with a common range of 8.4–8.7g/cm³.
Why does the density range vary?
It depends on the ratio of elements such as copper and zinc and whether it contains alloy components such as tin and aluminum; the higher the copper content, the greater the density.
What are the differences in density between different types of brass?
Yellow brass is about 8.47g/cm³, red brass is about 8.75g/cm³, and naval brass is about 8.4–8.7g/cm³.
How to measure the density of brass?
It is usually measured by the Archimedean method, density meter, or “mass ÷ volume” method.
What role does brass density play in engineering design?
It is related to material selection, weight calculation, and finished product quality control; density affects strength, corrosion resistance, and cost calculation.
How does the density of brass compare to other metals?
Slightly lower than pure copper (8.92g/cm³), higher than zinc (7.14g/cm³) and aluminum (2.7g/cm³), and slightly higher than steel.
How does brass density affect performance?
Brass with high density is usually harder, more wear-resistant, and has better conductivity and density; but its plasticity will be slightly reduced.