工程训练知识点英文.docx

1、工程训练知识点英文Knowledge Point 1: Engineering Materials and Heat Treatment A material ? Material: metal materials, non-metallic materials; ? Metallic materials: ferrous metals, non-ferrous metals; ? Material properties: performance (mechanical properties, physical properties and chemical properties, etc.)

2、 and process performance (casting properties, weldability, Pressure processing performance, cutting and heat treatment performance); ? Mastered common carbon steel (carbon steel Q235, 45 high-quality carbon structural steel, carbon tool steel T8, T12), alloy steel (in On the basis of carbon steel al

3、loying elements added, making the performance of the material increase or have special properties) and cast iron (HT200, KTH330-08) of Classification, grade, performance, applications. Second, the heat treatment of steel ? Heat treatment concept ? Heat treatment of steel are the basic process: annea

4、ling, normalizing, quenching and tempering. 1, the annealing - heated to a certain temperature, the furnace was cooled after the incubation. 2, the normalizing - heated to a certain temperature, the cooling after the heat in the air. 3, the quenching - is heated to a temperature above the critical t

5、emperature, the rapid cooling after the heat (i.e., greater than the critical cooling rate). 4 and tempering - after quenching the workpiece reheated to a temperature below the critical point, slow cooling after prolonged incubation. Can be divided into: tempering (150 250 ) The purpose is to elimin

6、ate and reduce stress and brittleness of hardened steel to improve the toughness, the part having a higher Hardness (58 64HRC). Mainly used for a variety of workers, the amount of molds and rolling bearings, etc., as with T12 steel saw blade, file, etc., generally Are used after quenching and temper

7、ing. tempering (350 500 ) decreased the hardness of the workpiece after tempering, but steel can obtain a higher elastic limit and strength (35 45HRC). Mainly used for heat treatment of various springs. tempering (500 650 ) usually steel after quenching and tempering, called quenching. After quenchi

8、ng parts, both Has a certain strength, hardness, but also has a certain plasticity and toughness, that better mechanical properties (25 35HRC). Mainly used for shafts, gear Wheel, connecting rod and other important structural components. Such as various types of shafts, gears, connecting rods such a

9、s the use of carbon steel, after quenching and tempering can be achieved using Performance requirements. General with the tempering temperature, strength and hardness of steel decreased, while the plastic toughness rise. Knowledge Point 2: Casting Casting is metal smelting, manufacturing and molten

10、metal is poured into the mold and parts adapted to the shape of the mold, after the solidification get a Casting molding method and the performance of a given shape. Castings are generally not high dimensional accuracy, surface roughness of the rough must be approved cutting After processing in orde

11、r to become parts. If you do not ask for the part surface, can also be used directly. First, the characteristics and applications of casting 1, features 1) and the shape of the cavity may be made of casting very complex castings, in particular a blank having a lumen, such as various housings, gas Cy

12、linder block, cylinder head, etc. 2) casting adaptable and can be used a variety of materials, such as non-ferrous metals, ferrous metals, iron and steel, etc., but in black Color metal-based; produce different size and quality of the castings, such as the wall thickness can be less than 1mm, the qu

13、ality of castings can light To a few grams, weighing hundreds of tons of castings. Low 3) casting production costs, less investment in equipment, low raw material prices, and wide sources. So casting is widely used in machinery manufacturing, but the casting is difficult to precisely control the pro

14、duction process; casting of Chemical composition and organization is not very uniform, coarse grains, loose tissue, often pores, slag, sand holes and other defects, making High mechanical performance than forging shortcomings. But with new technology, continuous development of new materials, the qua

15、lity of the casting is also rising. 2, the application Mainly used in the low speed gear box and the various non-load bearing or the like. Such as the machine bed, gearbox, gearbox, hand wheels, Internal combustion engine cylinder block, cylinder head, the train wheels, pulleys, vise clamp holder an

16、d so on. Many casting production methods can be divided into two categories: sand casting; special casting. Second, the type (core) sand - sand core performance requirements than ordinary sand higher overall performance. Third, the casting process 1, casting the main process parameters to determine

17、Shrinking margin the draft angle of the allowance of the height of the size of the draft angle of the wall, molding method, the mold Sample materials and surface roughness and so on. cast holes, slots and core cast rounded head 2, the molding process The process must take into account the main probl

18、em is the sub-surface and pouring system modeling, they directly affect the quality and raw castings Yield rate. 1) to determine the sub-surface is the sub-surface of the upper and lower contact surface of the sand. Parting surface to determine principles: parting surface should be selected at the a

19、ppearance of the largest cross-section; should make important face-down on the casting process or in a vertical position; should make all or most of the sand casting in the same box, in order to reduce the wrong box and improve casting accuracy. 2) to determine the gating system Pouring liquid metal

20、 into the system refers to the mold channel, and can be smoothly introduced into the liquid metal mold, should be conducive to retaining Residue and exhaust, and to control the order of solidification of the casting. Such as gating system opened well, easy to produce castings poured insufficient, sh

21、rinkage, Cold shuts, cracks and inclusions and other defects. Typical gating system generally includes: puddle - pouring of the liquid metal buffer the impact force-fitting and separation of the slag. sprue - connecting the vertical channel of the outer gate and runner, using its height so that the

22、molten metal to produce a certain static pressure And quickly filled cavity. runner - connecting sprue and runner, is located above the runner, steady flow of liquid metal, the metal fluid level Steady inflow to the cavity through the sprue and runner assigned to each liquid metal and slag from the

23、role. Within runner - channel directly connected to the cavity, the cavity can be controlled liquid metal flows into the position, speed and direction. Riser: mainly from feeding effect. But also both exhaust, scum and observe the flow of liquid metal and so on. General Security On top of the wall t

24、hickness. Fourth, smelting equipment Cast - cupola; steel - EAF; non-ferrous metals - crucible furnace. V. Special Casting 1, metal casting 2, investment casting 3, pressure casting 4, centrifugal casting centrifugal casting is under the effect of centrifugal force, so dense, no shrinkage, porosity,

25、 slag eyes, etc. Defects, and therefore better mechanical properties. Foundry casting hollow rotating body does not need cores and gating system, casting does not need to fill riser Shrink, labor and material, high productivity, good quality and low cost. Six modeling technique Seven, modeling metho

26、ds Modeling methods are hand molding and machine modeling. Manual modeling methods: entire mold two box modeling, parting two box modeling, styling and false Washa box modeling, live a block shape, scraper Modeling, three box shape. Eight, making the core The main role of the lumen forming the core

27、of the casting. Nine, pouring temperature Pouring temperature is low, the liquid metal poor mobility, easy pour enough cold shuts, porosity and other defects; pouring temperature is too high, Casting shrink large, easy to produce shrinkage, cracks, coarse grains and sticky sand and other defects. Su

28、itable pouring temperature should be based casting alloys Type, size and shape of the casting is determined. Knowledge Point 3: Pressure Processing First, the pressure processing characteristics and application Forging press working part of metal, which is an external force applied to the blank, to

29、produce plastic, changing the shape and size and improving the performance, In forming method for manufacturing mechanical parts, the workpiece or blank. It is the forging and stamping in general. 1, features After forging metal materials, its organization and performance have been improved, especia

30、lly cast structure. After forging, or by press working, the internal Defects such as micro cracks, porosity, shrinkage defects get pressed together, so that the structure of dense, fine grain, greatly improving the mechanical properties. And castings, Compared weldment, forging process generally onl

31、y get rough shape simpler parts. 2, the application Those who bear the heavy load of machine parts, such as spindles, crankshafts, gears and so on. The main method of metal pressure processing are rolling, drawing, extruding, forging freedom, forging and sheet metal stamping. Forging equipment is un

32、der pressure and working (mold) with the role of part or all of the blank to produce the plastic deformation, to achieve certain geometric foot Size, shape and quality of forging processing methods. By forming methods, free forging and forging model can be divided into two categories forging. Second, the metal is heated General malleable metallic materials commonly used to measure plasticity and deformation resist