文献翻译材料的处理和特性Word文件下载.docx

1、Many of the projects or products made in the machine shop have little or no value until they are heat-treated. This article includes only the most elementary information about the heat treatment of steel. Heat treatment can also be done on many of the nonferrous metals such as aluminum, copper and b

2、rass. The procedures are different, however, and will not be considered here. The procedures of heat treatment of steel include hardening, tempering, annealing, and case hardening.Hardening Hardening is a process of heating and cooling steel to increase its hardness and tensile strength, to reduce i

3、ts ductility, and to obtain a fine grain structure. The procedure includes heating the metal above its critical point or temperature, followed by rapid cooling. As steel is heated, a physical and chemical change takes place between the iron and carbon. The critical point, or critical temperature, is

4、 the point at which the steel has the most desirable characteristics. When steel reaches this temperaturesomewhere between 1,400 and l600Fthe change is ideal to make for a hard, strong material if ft is cooled quickly. If the metal cools slowly, it changes back to its original state. By plunging the

5、 hot metal into water, oil, or brine （quenching）, the desirable characteristics are retained. The metal is very hard and strong and less ductile than before.Heating is done in a furnace fired by gas, oil, or electricity. A device called a pyrometer is attached to the furnace. This accurately registe

6、rs the exact temperature in the furnace. The temperature of the metal can also be determined by observing its colour. You can make use of the colours when heat-treating simple metal parts and tools. Colours are not very accurate, however. Even the expert heat-treater will be off as much as 20F from

7、the true temperature.The hardening procedure is:1. Point of stoves to reach the appropriate temperature 2. The metal into stoves, heating it to the critical temperature for carbon tool steel, in order to achieve this temperature, each one-inch thick about 20-30 minutes. In order to quench temperatur

8、es reached are hot, each one-inch thick about food warming 10-15 minutes. 3. Choose the appropriate coolant. Certain steels in the water cooling, while others steels in oil or water to cool. Water-carbon steel hardening is the most widely used coolant. Because water prices cheap effect. Saline water

9、 is usually added to the 9% in the ordinary salt produced. Saline help to achieve a more uniform hardness for the whole parts faster cooling. Some oil will quench slower pace. Most quench oil is mineral oil 4. Remove with tongs heated metal to vote people coolant. Thick metal coolant to enable rapid

10、 and uniformly cool. If this is the final piece of thin （like knives or leaves）, to quench her while coolant to be Qiaoqu. If side cooling faster than the other side, it will produce a certain Qiaoqu. 5. The normal hardening tool steel will stiffen Biancui and have high tensile strength. It will als

11、o have to stress. If left in this state, which would make the metal occurred within stress cracks.Flashback arrestors a lower hardness and intensity and enhance resilience approach. It can eliminate the brittleness quench her. Crowded in the hardening of the metal to stiffen after a change in person

12、al ways. Flashback is to re-heating the metal to a low or moderate temperature, and then Jileng or in the air cooling. When metal crowded heating, but also changes in their colour. These colours called tempering color. These can be observed from time to know what colour to the temperature. Of course

13、, a more precise method is observation of high-temperature. Many parts and products are to the overall backfire. Others are part of the flashback, and the remainder are still in the hardening state.Tempering method is as follows : 1. The flashback to the overall, the entire working to put stoves Lan

14、e. Further heating to the appropriate temperature to achieve the required strength and resilience. Remove the metal and rapid cooling. 2. Small cutting tools for the flashback :A. The entire machine tool hardening, using emery cloth to remove oxide skin B. Of a piece of scrap metal to Chek thermal h

15、eating degree. C. On the metal cutting tools, the edge of blade Department placed outside this Chek hot metal D. Observer crowded color, when appropriate tool edge of blade colors to the Department, it Jileng.Anneal anneal is to soften the steel to eliminate internal stress approach. This will enabl

16、e the steel easier processing. Steel heated to a temperature above the threshold and then slowly cooling. The most commonly used method is to heat the steel to stoves have it revealed. Then turn the stoves for metal slowly cooling. Another method is to use metal clay packs up and heating it to the c

17、ritical temperature, then remove from stove, let it cool slowly.Case is harder to quantify black metal case, the surface or the interior floors. Through carbon added to a low-carbon steel surface, a heat treatment to the surface it can stiffen, and the center, that is, core and the Department remain

18、s soft resilience.There are many ways to measure the surface. In industry, the use of melting of cyanide （which called cyanidation）. Another method is carburization industrial law. This is a one of the ways to use carbon from the。Dead, piston sales and other must withstand vibration and wear a lot o

19、f parts of the Act can be used for processing. However, the law must not be used for any benefit to himself the final.Mechanical properties of metalMechanical performance is material plus loads role in the emerging identity of the measure. In other words, the mechanical properties of metals is in a

20、role of power or more power, with the intensity. They know the intensity of metal performance can build a solid security structure, the intensity is carrying a payload of metal （external forces） without fracture capacity.Intensity characteristics usually refer to the tensile strength, Kangwan intens

21、ity, and compressive strength, Kangniu intensity, and beam intensity, fatigue strength and impact strength. 1. Stress is a material internal resistance deformation capacity through additional load to measure stress 2. Response by the stress arising from the deformation. Response to the size of each

22、cm deformation to express 3. Metal fracture or deformation in a flexible, external forces back to their original shape when removed. Rubber-band is what is the best example of flexibility. Rubber arm, if knob loosened, it would revert to the original shape. However, if more than a rubber arm was, it

23、 would break. Flexible metal also have the same character. 4. Limit is flexible material in stretch, added stress is not removed after they return to the former state of deformation of the greatest stress. . Flexible modules within the limits of flexibility in the volume stress and pull over. Must s

24、tress role in the deformation of materials smaller, higher volume flexible modules. Through more flexible modules of the size, we can easily identify the relative supply of different materials. For many machines and structures, chemical or cut is very important. 6. Tensile strength is the resistance

25、 of the metal to pull it off the outside. It is more important to identify the target metal one. 7. Compressive strength is the resistance of metal crushing capacity. On the role of load direction, and stretch compression precisely the opposite. Most metals have a high tensile strength and compressi

26、ve strength. However, the brittleness materials such as cast iron high compressive strength, but only a medium tensile strength 8. Kangwan intensity resistance is the role of external forces cause components along the loading direction bending or curving nature. Indeed, the bending stress is a combi

27、nation of pulling stress and pressure stress 9. Kangniu intensity is caused by the metal components to reverse the capacity to resist external forces 10. Sheared intensity refers to the size of the two components in the opposite direction of equal role, how strong its capability to resist 11. Fatigu

28、e strength is the resistance of various materials to the rapidly changing nature of the stress. For example piston rod or axle withstand the pressure for change is widening stress. Both sides of the winding up of tinsel fatigue fracture is another example. 12. Intensity of the impact resistance of m

29、etals is often rapid and sudden increase in load payload capacity. The impact of higher metal intensity, the energy needed to break on older. Welding will seriously affect the impact intensity, because the impact of structural strength is a sensitive nature. 13. Resilience is metal fracture, bending

30、 or reverse without breaks or damage. Resilience high metals, such as copper or wrought iron, with the load increase is the gradual damage or fracture. Resilience and low metals such as cast iron, when carrying heavy, will suddenly rupture and damage. 14. Hardness is steel or penetration resistance

31、Yahen nature. Hardness is usually used in the standard payload Gangqiu role of the designer to express Yahen area, or used in a particular load role of the indenter specialized formed to express the depth. 15. Cryogenic nature expressed in very low temperature environment in the role of metal stress performance changes. In addition to the crystal structure and processing conditions are ve