The requirement of smelting NTN bearing steel material

Sheet metal pieces of fixture design on automatic lathe turning 3 cr13 stainless steel parts. Processing technology and equipment selection of auto longeron G76 thread cutting composite cycle instruction coordinate system and the movement direction. Introduction gantry wedm decoding simulation program design based on UG CAD/CAM software function under the new type of mouse design and manufacture of machine tool association: towards a 'high-quality goods service brand association' to continue efforts to inverter principle introduction seiko introduced low-power high ripple suppression voltage stabilizer rolling wheel sand mixer operation procedures. Bearing superfinishing machine tool equipment developed by breakthrough metal cutting processing of waste liquor of citic juki made heavy double column vertical lathe, with neat one cylinder head valve seat and catheter hole processing technology AC610M/AC630M precision turning platform of typical CAM nc milling programming function. Application of world machine tool industry development direction of the whole analysis how to solve the Pro/E engineering drawing in Chinese characters garbled problem after turn AutoCAD. Detection technology in the application prospect of car manufacturing structure material friction wear lubrication bearing corrosion strength capacity alloy bearing NTN bearing directly connect with part load bearing with relative motion to reduce friction and wear bearing friction material request all kinds of requirements. Friction coefficient wear-resisting meet with enough the compressive strength, fatigue strength ability to withstand shock bearing alloy thickness of 0. 0130. 13 mm sticky load speed bearing gap is too small surface roughness note carefully selected material matching to prevent poor lubrication. Bearing on the bearing seat, with the shaft directly contact part of the load bearing shaft and have relative motion. About 5% of chromium and contains a small amount of manganese and silicon hypereutectoid steel. Chromium heat treatment can improve performance, increase the hardenability, uniformity, tempering stability, and can improve the anti-corrosion properties of steel and grinding performance. 65% when, after quenching can increase the retained austenite in the steel, reduce hardness and dimensional stability, increase the inhomogeneity of carbide lower impact toughness and fatigue strength of steel. To this end, the chromium content of high carbon chromium bearing steel general control under,65%1. Only strict control of the bearing steel chemical composition, can through the heat treatment process to satisfy the bearing performance of the organization and hardness. Second, the size of the high precision demands of rolling bearing steel steel dimension precision is higher, this is because most of the bearing parts, it takes pressure molding. In order to save material and improve labor productivity, the vast majority of NTN bearing ring have been forging forming, steel ball is through cold heading or hot forming, small size of the roller is also through the cold heading forming. If the size of the steel precision is not high, will not be able to accurately calculate the expected size and weight, and cannot ensure the quality of bearing parts, also easy to cause damage of equipment and dies. Three, particularly strict purity requirements of steel purity refers to contain nonmetallic inclusion in steel, the higher the purity, the less the non-metallic inclusions in steel. Harmful oxide and silicate inclusions in bearing steel bearing early fatigue is the main cause of peeling, significantly reduce the bearing life. Especially brittle inclusion most harmful, because in the process of peeling off easily from the metal substrate, seriously affect the quality of bearing parts after finishing surface. Therefore, in order to improve the service life and reliability of the bearing, must reduce the content of inclusions in bearing steel. Four, the strict macrostructure and microstructure, At high magnification) Organization for bearing steel macrostructure is refers to the general loose, loose and flat body center, microscopy ( At high magnification) Organizations including steel annealing, carbide network, ribbon and liquid, etc. The dangers of carbide liquid chromatography were hard and brittle, it is the same as the brittle inclusion. Carbide network to reduce the impact toughness of steel, and made it the organization is not uniform, easy to deformation and cracking during quenching. Banded carbide annealing and quenching tempering and contact fatigue strength. Low and high power of the organization's performance and service life of the advantages and disadvantages of NTN bearing has a great influence, so, in standard bearing materials have strict requirements on low and high power organization. Five, particularly strict surface flaws and internal requirements for bearing steel, surface defects including cracks, slag inclusion, burr, scarring, scale, etc. , internal defects including shrinkage cavity, bubbles, white spots, such as severe osteoporosis and segregation. These defects for the processing, the bearing performance and life of bearing has a great influence, explicitly stipulated in the standard NTN bearing materials don't allow these defects. Six, particularly strict carbide inhomogeneity requirements in bearing steel, if there is a serious uneven distribution of carbide, is in the process of heat treatment process is easy to cause tissue and uneven hardness, the organization of the steel inhomogeneity has a larger effect on contact fatigue strength. In addition, serious inhomogeneity carbide bearing parts during quenching cooling could produce cracks, carbide non-uniformity also can reduce the service life of bearing, therefore, in the bearing material standard, with different specifications of the steel have clear special requirements. Seven, particularly strict surface decarburization layer requirements in NTN bearing material standard has strict rules on steel surface decarburization layer, if the surface decarburization layer beyond the prescribed scope of the standard, and before the heat treatment process, and there is no clear away all the, is in the process of heat treatment quenching is prone to quenching crack, cause scrap parts. Eight, other requirements for bearing steel in bearing steel material standard of smelting method, hardness, fracture, oxygen content and annealing residual elements, spark test, delivery status, identity, and so on have strict requirements.