PEI plastics (polyetherimide plastics) is an amber transparent solid. It has an inherent flame retardancy and low smoke concentration without adding any additives. The oxygen index is 47%, and the combustion level is ul94-v-0, and the density is 1.28~1.42 g/cm3.
PEI plastics has a strong thermal stability, and even the non-enhanced PEI plastics still has good toughness and strength.Therefore, the high thermal stability of PEI plasticsis used to make high temperature heat-resistant devices.
PEI plastics has excellent mechanical properties, electrical insulation performance, radiation resistance, high temperature resistance and abrasion resistance, and can be used by microwave.The PEI plastics also has good flame retardancy, chemical resistance and electrical insulation.Vitrification transformation temperature is very high, up to 215 ℃.PEI plastics also has a very low shrinkage rate and good mechanical properties.Adding fiberglass, carbon fiber or other fillings to enhance the purpose of modification;And other engineering plastics of heat-resistant polymer alloys, can be in 160 ~ 180 ℃ under the working temperature of use for a long time.
The long-term use of polyether amines in the us underwriters laboratory is 338T and 356T (according to the grade), and the combustion rating reaches UL94V - 0 (10 mille thickness).The oxygen index is 47, and the polyetherimide is in line with the requirements of the aircraft for the requirements of the FAA's flame retardant and thermal release material standards.It has a glass transition temperature of 419F and is allowed to be used intermittently under 392F, at higher temperatures, resulting in a short-term shift.Under 356T, the tensile temperature and flexural modulus were above 41 and 2068MPa respectively.The material reinforced with Glass Fiber and carbon fiber has higher strength and rigidity under the transition temperature of glass.
PEI plastics long-term resistance to creep under high temperature and stress allows it to replace metals and other materials in many structural devices.PEI plastics shows good performance in variable temperature, humidity and frequency.The low dissipation factor at GHz frequency makes the polyetherimide have high microwave wearability.Its ionic pollutant is low, at 250F100 % R.H.And 207kPa after 120 hours of water extraction with the conductivity, at 20 megaohm, it can be used as an electronic sensor element insulation.
PEI plastics is a fine coating and film forming material which can be used for the coating and film of electronic industry, and can be used in manufacturing aperture < 0.1 mu m, with high permeability microporous diaphragm.It can also be used as high temperature adhesive and high strength fiber.
Application field
Since PEI plastics has excellent comprehensive and balanced performance, PEI plastics has been applied to the departments of electronics, motor and aviation, and used as metal substitute materials for traditional products and cultural life supplies.Using PEI plastics instead of metal to make optical fiber connector, PEI plastics can optimize the structure of the component, simplify its manufacturing and assembly steps, and maintain a more precise size.Used in automobile industry, such as high temperature fittings for manufacturing, the high power lamp and light, control the car cabin outside temperature sensor (air conditioning temperature sensor) and the control of air and fuel mixture temperature sensor (effective combustion temperature sensor).Also can be used for high temperature erosion of lubricating oil vacuum pump impeller, distilling apparatus that operate at 180 ℃ of ground glass joints (following), the lighting of anti fog light reflector.
Pei Plastic Rod,Polyetherimide Plastic Rod,Esd Pei Plastic Rod,Conductive Pei Plastic Rod Dongguan Noegem Plastic Products Co.,Ltd , http://www.noegempLastic.com
/*728*90 created on 2018/5/16*/ var cpro_id = "u3440131"; Home>Bearing Knowledge>Influencing SKF Bearing Grinding Metamorphic Elements Affecting SKF bearing grinding enthalpy layer elements
There are two main factors affecting the SKF bearing grinding enthalpy layer; the effect of SKF bearing grinding force and grinding heat. /*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';
1. Grinding force is in the grinding process; the outer surface of the workpiece will be affected by the cutting force, tightening force and friction force of the grinding wheel. Especially the effect of the latter two; the outer surface of the workpiece constitutes a strong directional plastic deformation Layer and work hardening layer. These metamorphic layers must affect the change of residual stress in the outer layer.
(1) The cold plastic deformation layer is 6206 bearing during the grinding process; each moment the abrasive grain is equivalent to a cutting edge. However, in many cases, the rake angle of the cutting edge is negative; the abrasive grain is in addition to the cutting effect; The workpiece is subjected to a kneading effect (ploughing effect); the surface of the workpiece is left with a significant plastic deformation layer. The degree of deformation of the deformation layer will increase with the degree of grinding of the grinding wheel and the increase of the grinding feed. Big.
(2) Thermoplastic deformation (or high temperature deformation) The instantaneous temperature of the layer grinding heat on the outside of the work; the 6206-2RS1 bearing makes the elastic limit of the outer surface of the workpiece at a certain depth sharply decrease; even the degree of elasticity is not visible. Under the effect of grinding force; especially the effect of tightening force and friction; the spontaneous expansion caused by the base metal; the outer surface is tightened (more plough); the plastic deformation is formed on the outer surface. The high temperature plastic deformation is in the grinding process. In the case of constant; increase with the increase of the external temperature of the workpiece.
(3) The work hardening layer can sometimes be found by microhardness method and metallographic method; the hardness of the outer layer is increased due to processing deformation.
2, grinding heat in the grinding process; grinding wheel and workpiece touch area; cost a lot of energy; a lot of grinding heat occurs; part of the instantaneous high temperature forming the grinding zone. Using linear motion heat source heat transfer theory formula derivation, SKF bearing calculation or the instantaneous temperature under the conditions of the infrared method and the thermocouple method; the instantaneous temperature in the grinding zone can be as high as 1000-1500 ° C in the range of 0.1 to 0. 001 ms. High-temperature oxidation of the outer surface of the work surface with a certain depth of appearance; amorphous arrangement, high temperature tempering, secondary quenching; and even burn cracking and other changes.
(1) The effect of the outer surface of the SKF bearing on the surface of the steel and the oxygen in the air; the thin layer of iron oxide which is extremely thin (20-30 nm). It is worth noting that the thickness of the oxide layer and the surface grinding The total thickness test results are in a corresponding relationship. This indicates that the thickness of the oxide layer is directly related to the grinding process; it is an important mark of the grinding quality.
(2) The amorphous state arranges the instantaneous high temperature of the grinding zone to make the workpiece surface reach the molten state; the molten metal molecular flow is uniformly applied to the work surface; and is cooled by the base metal at a very fast speed; Very thin layer of amorphous arrangement. It has high hardness and resistance; but it only needs about 10nm; it is very simple to be removed in fine grinding.
(3) The instantaneous high temperature in the grinding zone of the high temperature tempering layer can be heated to a temperature higher than the tempering heating temperature of the workpiece at a certain depth (10 ~ 100nm). In the case of not reaching the austenitizing temperature; The improvement of the heating temperature; the appearance of the layer will be re-tempered or high-temperature tempering corresponding to the heating temperature; the hardness of the 6206-2RS1 bearing will also decrease. The higher the heating temperature, the more fierce the hardness is.
(4) Two-layer quenching layer of SKF bearing When the instantaneous high temperature of the grinding zone heats the outer surface of the workpiece to above the austenitizing temperature (Ac1); the austenitizing of the layer is arranged in the subsequent cooling process; It is quenched from the head into a martensite arrangement. However, any workpiece with secondary quenching burns must have a very high hardness tempering layer under the secondary quenching layer.
(5) Grinding cracks Secondary quenching burns will change the stress of the outer surface of the workpiece. The secondary quenching zone is under pressure; the maximum tensile stress exists in the high temperature tempering zone below; here is the most likely crack center The local .6206 bearing crack is most simply conveyed along the original austenite grain boundary. Severe burns will cause the entire grinding surface to appear cracks (more cracks) to form the workpiece.
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Source: China Bearing Network Time: 2017-11-02