Views: 157 Author: Site Editor Publish Time: 2017-02-10 Origin: www.fuchun-casting.com
Each and every component in an automobile has significance. Modern day vehicles have become a great deal more complex and have many more electronic parts than the muscle cars of the past. Although there are many complex parts included in modern automobiles, some of the parts are a mainstay — common and essential for every vehicle. Some of the important components include:
Engine: One of the most important components of a vehicle includes the engine. This is the most important component of an automobile. Different types of fuels are used by engines like diesel, ethanol, gasoline, and now even electricity. The performance of a vehicle depends on its engine and it is the heart of every car.
Gear Box (Transmission): This is also known as transmission which has a number of gears in it. These gears transfer the engine’s power to the wheels of the vehicle. There are many types of gearbox parts in different cars. A transmission is available in two types: the manual and the automatic models. As the speed of the vehicle varies, the gears can be switched from one ratio to another. The power of the engine is transferred to the wheels of the vehicle with the help of the gears. Nowadays, most of the vehicles have automatic gears or transmissions. The gear box is one of the most difficult parts of the vehicle to work on.
Brakes: Another extremely important component of a vehicle is the brakes which help reduce and halt the speed of the vehicle. When the brakes are applied, a hydraulic fluid is transmitted through the steel pipes to the wheels of the vehicles. Obviously, the failure of this system may lead to some serious accidents. Though previously the entire system used to work upon human intervention, nowadays sensors are being installed in cars so that the car itself can sense the necessity of braking and take action. Whether you have a manual or sensor braking system, it is very important to maintain the break parts such as break pads.
Drive Axle: Another important component includes the drive axle which helps propels the vehicle. Think of it as a large bar connecting the two wheels. The drive axle allow the vehicle's operator to turn the wheels and control the vehicle. This is one of the largest auto parts in every car.
Oil Filters: Filters are essential in removing dust and abrasive particles from the engine oil. Such particles can harm the engine and prevent proper functioning. Oil filters are mainly used to segregate the engine oil from unwanted debris and dust particles. Most of the oil filters are classified as high efficiency filters as it segregates abrasive materials from the engine oil.
Chassis: The automotive chassis is the frame of the vehicle which supports the various parts such as engine, brakes, steering, axle, tires and so forth. If the engine is the heart of the vehicle, the chassis is the skeleton. It is the most important structure of the vehicle. Automotive chassis are usually made of light steel material or other sturdy materials like aluminum. The chassis keeps the vehicle stiff and tensile. It ensures low vibration and noise in the entire vehicle. There are various types of chassis used in vehicles which include the backbone chassis, ladder chassis and the monochrome chassis. These days most of the vehicles use steel plated chassis as it ensures strength and durability.
This is where a batch of steel meets more than one specification or grade. It is a way of allowing melting shops to produce stainless steel more efficiently by restricting the number of different types of steel. The chemical composition and mechanical properties of the steel can meet more than one grade within the same standard or across a number of standards. This also allows stockholders to minimise stock levels.
For example, it is common for 1.4401 and 1.4404 (316 and 316L) to be dual certified - that is the carbon content is less than 0.030%. Steel certified to both European and US standards is also common.
There are many different types of surface finish on stainless steel. Some of these originate from the mill but many are applied later during processing, for example polished, brushed, blasted, etched and coloured finishes.
The importance of surface finish in determining the corrosion resistance of the stainless steel surface cannot be overemphasised. A rough surface finish can effectively lower the corrosion resistance to that of a lower grade of stainless steel.
Various types of stainless steel are used across the whole temperature range from ambient to 1100 deg C. The choice of grade depends on several factors:
In the European standards, a distinction is made between stainless steels and heat-resisting steels. However, this distinction is often blurred and it is useful to consider them as one range of steels.
Increasing amounts of Chromium and silicon impart greater oxidation resistance. Increasing amounts of Nickel impart greater carburisation resistance.
Austenitic stainless steels are extensively used for service down to as low as liquid helium temperature (-269 deg C). This is largely due to the lack of a clearly defined transition from ductile to brittle fracture in impact toughness testing.
Toughness is measured by impacting a small sample with a swinging hammer. The distance which the hammer swings after impact is a measure of the toughness. The shorter the distance, the tougher the steel as the energy of the hammer is absorbed by the sample. Toughness is measured in Joules (J). Minimum values of toughness are specified for different applications. A value of 40 J is regarded as reasonable for most service conditions.
Steels with ferritic or martensitic structures show a sudden change from ductile (safe) to brittle (unsafe) fracture over a small temperature difference. Even the best of these steels show this behaviour at temperatures higher than -100 deg C and in many cases only just below zero.
In contrast austenitic steels only show a gradual fall in the impact toughness value and are still well above 100 J at -196 deg C.
Another factor in affecting the choice of steel at low temperature is the ability to resist transformation from austenite to martensite.
It is commonly stated that “stainless steel is non-magnetic”. This is not strictly true and the real situation is rather more complicated. The degree of magnetic response or magnetic permeability is derived from the microstructure of the steel. A totally non-magnetic material has a relative magnetic permeability of 1. Austenitic structures are totally non-magnetic and so a 100% austenitic stainless steel would have a permeability of 1. In practice this is not achieved. There is always a small amount of ferrite and/or martensite in the steel and so permeability values are always above 1. Typical values for standard austenitic stainless steels can be in the order of 1.05 – 1.1.
It is possible for the magnetic permeability of austenitic steels to be changed during processing. For example, cold work and welding are liable to increase the amount of martensite and ferrite respectively in the steel. A familiar example is in a stainless steel sink where the flat drainer has little magnetic response whereas the pressed bowl has a higher response due to the formation of martensite particularly in the corners.
In practical terms, austenitic stainless steels are used for “non-magnetic” applications, for example magnetic resonance imaging (MRI). In these cases, it is often necessary to agree a maximum magnetic permeability between customer and supplier. It can be as low as 1.004.
Martensitic, ferritic, duplex and precipitation hardening steels are magnetic.