Simple history
Metal plastic processing technology appeared in the history of metallurgy. The products that have been discovered are the first 5 millennium BC. The earliest iron made of iron is the earliest of the first 4 millennium BC. China has found the earliest iron artifacts in the middle of the business episode unearthed in Hebei Province (about 13th century bodies in the first 13th century). Research proves that these natural metal products are forged. The ancient China Metallurgical Technology is more advanced in Europe, but is ignored by casting techniques and neglects metal plastic processing, which has never developed rolling production. The production process described in the "Tiantong Opening" described in Song Yingxing (1587 ~?) In the Ming Dynasty, the production process described in the "Tiangong Opening" described in the Ming Dynasty, but the long-term stay in the manual stage later. After the industry revolution, Europe's metallurgical industry quickly moved to modernization. By using dynamic machinery, metal plastic processing is also turned to modern major industrial production. In 1766, a boreal rolling mill appeared in 1836, a two-roller and three-rolling mill driven by a steam engine occurred. China's modern metallurgical technology (including plastic processing technology) is introduced by Europe. China's modern rolling mill is the earliest is the latte (rolling steel) plant from the Fuzhou Shipping Bureau in the 1871. In the future, there is a small and medium-sized mill in the 800mm rail mill built in 1894 and the subsequent Shanghai, Tianjin, Taiyuan and other places. After 1931, Japan was built in Anshan, Liaoning, has built a large-scale rolling mill and small mills of Benxi, Fushun and Dalian. In 1949, with the development of large-scale socialist economic construction, the rolling steel and non-ferrous metal processing industries were developed. By 1997, China's steel has reached 107.56 million t, and the steel production has reached 97 million T, ranking first in the world. Non-ferrous metal production reached 5.81 million t. Various types of rolling mills and metal processing plants have formed a system and reasonable layout.
Variety of plastic processing
Metal plastic processing, according to the process and deformed mode of the workpiece during processing, the basic plastic processing method has forging, rolling, extrusion, Several classes such as draw, draw, bend, cut, cut.
Forging
A processing method of compression deformation by a forging hammer of a forging press, there is free forging and die forging. Free forging does not require special molds, relying on the compression of the workpiece of the flat anvil, so that the workpiece is upset or eliminated, the processing accuracy is low, the productivity is not high, mainly used for single piece such as shaft, crank and connecting rods. Small batch production. The modifications of the die forging, the desformation of the next mold cavity, the components that can be machined and the size of the shape, suitable for large amounts of production, the productivity is also high, and it is a mechanical parts manufacturing to achieve less cutting or no An important way for machining.
rolling
causes compression deformation by rolling the rolling between two or more rotary rolls, so that the cross-sectional area is reduced and the shape change, and the longitudinal length increases. Processing method. According to the motion relationship between the rolls and the rolling, there are three ways of rolling, cross rolling and oblique rolling.
Squeeze
Make the blank inserted into the extruded cylinder, under the thrust of the rear end extrusion shaft, the mold hole of the front end of the extruded tube A processing method having the same shape of the extruded mold shape and dimension is obtained. Squeeze has two basic ways of positive extrusion and reverse extrusion. The direction of motion of the extrusion shaft is consistent with the direction of the metal flow extruded in the mold hole; when the reverse extrusion, the direction of motion of the extrusion shaft is opposite to the metal flow direction extruded from the mold hole. Extrusion method can be processed in a variety of complex section solid profiles, bars, hollow profiles and pipes. It is a colored metal profile, the main production method of pipe.
Pulling
Clamping the metal blanks passing through the drawing die, pulled out from the mold hole. A method of processing with the same shape and dimension is obtained. Pulling is generally carried out in cold state. Wires and pipes with small size. As a metal line having a diameter of 0.015 mm, the diameter is 0.25 mm pipe. The drawing article has a high dimensional precision, high surface finish, high strength (strong due to strong cold processing). Things, pipes, and profiles of various sections can be produced, which are widely used in wires, cables, metal network cables and various pipe production.
Degeneration
is also called stamping, relying on the punch to generate the metal sheet into the concave mold to produce a puller deformation, and obtain various cups, barrels and shells A processing method of body. Stamping is generally carried out at room temperature, and its products are mainly used in various housing parts, such as airplane skin, automotive cover, bullet case, instrument parts, and daily utensils.
Bend
Under the action of bending moment, a sheet of processing is made of a sheet or a tube, a bar, and a bar material.
Shear
The blank produces shear under the action of shear. A common processing method for punching the plate and the cutting of sheets and profiles.
Characteristics of plastic processing
Metal plastic processing with metal casting, cutting, welding, etc., there is a feature:
(1) metal plasticity Under the premise of processing of metal overall, it rely on plastics deformation material transfer to realize the shape and size of the workpiece, and does not produce chips, so the utilization rate is much higher.
(2) During plastic processing, in addition to the size and shape, the tissue and performance of the metal can also improve and improve, especially for casting, and the plastic processing will cause its structure to dense, thick Crystal crush refinement and uniform, thereby improving performance. In addition, the streamline generated by plastic flow can also improve its performance.
(3) Plastic processing process facilitates the continuous, automation of the production process, is suitable for mass production, such as rolling, drawing processing, etc., and thus labor productivity is high.
(4) The size precision and surface quality of the plastic processing product are high.
(5) The equipment is large and the energy consumption is high.
Application
Metal plastic processing Due to the above characteristics, not only the raw material consumption is less, high production efficiency, stable product quality, and effectively improves metal tissue performance. These technologies and economic unique and advantages have made it a very important means in metal processing, so it has a very important position in the national economy. For example, in the production of steel materials, in addition to a small part of the casting method directly produced into parts, more than 90% of the total output of steel and the total output of the non-ferrous metal need to be plastically processed, in order to meet mechanical manufacturing, transportation , Electric telecommunications, chemical, building materials, instrumentation, aerospace, national defense military, civil hardware and household appliances and other departments; and plastic processing itself is also an important processing method that often uses many departments directly manufacturing parts, such as automobile manufacturing, Many parts of ship manufacturing, aerospace, and civilian hardware and other departments must be manufactured by plastic processing. Therefore, metal plastic processing has a very important status in the national economy.
Plastic Processing Metal
According to the motion mechanism of metal crystal structure, research control and improve thermodynamics and mechanical conditions, in order to effectively carry out metal plastic forming professional basic theory discipline . The main research task of this discipline is to explore the appropriate thermodynamics and mechanical conditions for the metal and its alloys to produce plastic deformation under external force, seek to improve deformation performance, reduce deformation resistance (see metal deformed resistance), to avoid defects, reach after deformation The optimal crystalline state and performance process conditions for obtaining optimal internal and external quality products and reaches the target of energy saving. The main research contents of plastic machining metallics include:
(1) metal plastic deformation mechanism. The mechanism of the metal and its alloy produces plastic deformation under external force, study the effects and leading effects of internal and external conditional factors in the process of plastic deformation;
(2) metal yield Deformation resistance. The physical and mechanical conditions of the single crystalline metal are converted from the elastic deformation state to the plastic deformation state, and the force deformation resistance produced by the metal resisting plastic deformation changes with the development of the transformation;
(3 Thermodynamic conditions for metal plastic deformation. The effects of deformation temperature, deformation, deformation speed on metallic plasticity, deformation resistance, and crystalline tissue state;
(4) Changes in metal plastic deformation and tissue properties. The laws of metal tissue performance during plastic deformation are studied, and the product has achieved good performance;
(5) plasticity and breakage of metals. The ability to study the metal under certain conditions without creating a fracture, which promotes the conditions of metal to achieve the best plastic state and improve its plasticity;
(6) uneven deformation and residual stress. The causes of uneven deformation and expansion and the cause of adverse consequences were studied and the residual stress caused by the causes of reducing measures to prevent uneven deformation. Metal Plastic Processing Mechanics
Analysis of Mechanical Basic Theory of Mechanical Behavior and Law in Plastic Processing Deformation. The research task is to analyze the stress strain state and the deformation of the stress strain distribution law, determine the physical mechanical equation of the deformed material, and establish the analysis of the analysis of deformation and force parameters according to the basic equation of deformation mechanics and the characteristics of the plastic processing deformation process. In order to properly select the plastic processing deformed method, a reasonable process procedure, optimize design tool molds and processing equipment, analyze, and solve the product defect.
Plastic machining mechanics is based on the basic theory and method of plastic mechanics, and gradually formed with the development of metal plastic processing technology. In recent years, the requirements for the size accuracy of the processing products are increasingly strict, and the automatic control and adjustment of the production process is growing. These need to be more accurately grasp of metal deformation rules, more accurately calculate the power and elastic deformation of tools and equipment, which. It is more powerful to promote the continuous improvement of plastic machining mechanics. Especially in recent years, the development of electronic computing technology has also created conditions for the progress of plastic machining mechanics.
Multi-analytical methods for plastic machining mechanics have a wide range of applications: Engineering solution (see deformation mechanics engineering solution), slip line solution (see deformation mechanics slip line solution), upper bound law And finite element solution (see a finite element solution of deformation mechanics), and the like. With the development of electronic computing technology, various numerical calculations are attached, with nonlinear finite element method and composite parsing method.
Additionally, the experimental mechanical method of plastic processing, such as plasticity, optoplastic method, cloud line diaphragm, etc. also have new research progress.
The development trend of current plastic machining mechanics is:
(1) Research provides a more accurate deformation resistance model and formation equation for various actual materials under various deformation conditions;
(2) Type the type and different mechanism of workpiece and tool contact surface friction in plastic deformation, establish a more exact friction model;
(3) studies can reflect complexity More precise solution and simple practical calculation methods for the forming process.