Hi guys in this lecture we study the bearing material its properties and applications so lets go the details information,
Bearing Material, Its Properties and Applications
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| Bearing |
The most liked bearing material is Babbitt or white metal.
There are two variation of Babbitt
1) Lead base
2)Tin base
Depending upon major alloying element.
They are used in the form of strip or thin lining about 0.5 mm thick applied to steel shells. Babbitt's have very good conformability and embeddability.
Tin base Babbitt's have finer corrosion resistance and easily bond to steel shells.
High cost and shortage of tin are major limitations. Babbitt's weather lead base or tin base are essentially weak and strength reduce rapidly with increasing temperature. Their use is further compact due to poor fatigue strength.
The bearing materials are copper lead , aluminum alloys bronze and plastics. compared with Babbitt's bronze is stronger and cheaper and withstand high pressures. It has excellent casting and machining characteristics. They produce as single solid units. The main drawback of bronze bearing is their tendency to stick the surface at high temperatures.
What is bearing steel material?
Bearing steel is a type of steel specifically designed and optimized for use in bearings, which are mechanical components used to reduce friction between moving parts and support loads. The main characteristics of bearing steel include high hardness, wear resistance, and strong fatigue strength.
The composition of bearing steel typically includes high levels of carbon and chromium, along with other alloying elements like manganese, silicon, and sometimes molybdenum. These alloying elements contribute to the steel's properties, ensuring it can withstand the demanding conditions within bearings, such as high loads, repeated impacts, and continuous rotation.
Bearing steels are heat-treated to achieve the desired combination of hardness and toughness. Common grades of bearing steel include AISI 52100 (also known as SAE 52100), which is a chromium steel alloy that is widely used for making ball bearings due to its excellent hardness and wear resistance.
The production of bearing steel involves precise control over the chemical composition and manufacturing processes to ensure uniform properties and high performance in bearing applications. This steel is essential for the reliable and efficient operation of various types of bearings used across industries ranging from automotive and aerospace to industrial machinery and appliances.
What is the raw material of bearings?
Raw materials used in manufacturing bearings
Bearing Steel:
The primary material used for bearing components is specialized bearing steel, such as AISI 52100 (also known as SAE 52100). This steel is alloyed with high levels of chromium and carbon to provide excellent hardness, wear resistance, and fatigue strength.
Alloying Elements:
Bearing steel may also contain other alloying elements such as manganese, silicon, and molybdenum. These elements help improve specific properties like hardenability and toughness.
Rolling Element Materials:
For rolling element bearings (e.g., ball bearings, roller bearings), the rolling elements themselves can be made from different materials. Common materials include chrome steel (for balls) and through-hardened steel (for rollers).
Cage Material:
The cage that retains and separates the rolling elements in a bearing can be made from materials like brass, steel, or engineered polymers such as nylon or PEEK (polyether ether ketone).
Lubricants:
Although not a structural raw material, lubricants play a crucial role in bearing performance. Various types of lubricants, including oils and greases, are used to reduce friction and wear between bearing components.
Seals and Shields:
Bearings often incorporate seals or shields to protect against contaminants and retain lubrication. These components are typically made from rubber, plastic, or metal.
These raw materials undergo precise manufacturing processes, including forging, machining, heat treatment, and surface finishing, to produce bearings with the required performance characteristics for specific applications. The quality and selection of raw materials are critical to ensuring the reliability and longevity of bearings under various operating conditions.
What are the 5 types of bearings?
Following are types of bearing,
Ball Bearings:
Ball bearings are the most common type of bearings and use balls to separate the bearing races (inner and outer rings). These balls enable smooth rotation with minimal friction. Ball bearings can handle both radial and thrust (axial) loads.
Roller Bearings:
Roller bearings use cylindrical, tapered, or spherical rollers instead of balls to separate the races. This type of bearing can support heavier loads and is suitable for applications requiring high radial or axial load capacity.
a) Cylindrical Roller Bearings: These bearings have cylindrical rollers that provide good radial load capacity.
b) Tapered Roller Bearings:
Tapered rollers are used in these bearings, allowing them to support both radial and axial loads.
c) Spherical Roller Bearings:
Spherical rollers accommodate misalignment and heavy loads due to their self-aligning capability.
Needle Bearings:
Needle roller bearings use long, thin rollers (needles) that have a high length-to-diameter ratio. These bearings are compact and suitable for applications with limited space and high radial load requirements.
Thrust Bearings:
Thrust bearings are designed to support axial loads (parallel to the shaft's direction). They come in various configurations, including ball thrust bearings, roller thrust bearings, and thrust needle bearings.
Plain Bearings (Sleeve Bearings):
They have sliding surfaces that facilitate motion between the bearing surfaces. Plain bearings are used in applications where low friction and simple design are priorities.
These bearing types can further be categorized into subtypes and specialized designs based on factors like load capacity, speed capability, environmental conditions, and specific application requirements. Each type of bearing has unique characteristics that make it suitable for different industrial and mechanical applications.
Properties of a good bearing material-
1) It should high compressive strength to hold high pressures without deformation.
2) Bearing material should have capacity to yield and adopt its structure to that journal.
3)The dirt particles is lubricating oil tend to jam the gap space and if hard may cut scratch on the surface of bearing.The bearing material material should soft to allow these particles to get embedded in lining and avoid trouble.
4) In application like engine Bearing, the immoderate temperature causes oxidation of lubrication oil and form corrosive acids.
5) The bearing material should have sufficient corrosion resistance.
Applications Oof Bearing Material-
1) Grade 69 is used for under water applications and also used for gland packings.
2) Grade 60 is used for electric motor, centrifugal pump, dynamos and other speed applications.
3) Grade 6 used for heavy duty applications turbines and gross heads of steam engines.
4) Grade 5 used for railway carriages.
Chemical composition of these grades are given in table.
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| Grades |
So in this lecture we study bearing material, properties, applications and other information hope you understand well.
Any queries comment below. Thanks for reading.
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