Bending fatigue Bending fatigue is the most common form of fatigue failure. Shot blasting/shot peening is most effective in overcoming this failure because the surface of the part is the area where the tensile stress is concentrated. Cantilever beam under a bending load. The bending deformation of the beam causes its surface to be in an outwardly tensile tensile stress state. Any change in the radius or geometry of the surface layer will cause an increase in tensile stress. This is the most damaging fatigue load scenario with completely reverse bending and the part being subjected to tensile and compressive stress cross-crossing stresses. The tensile stress portion in the alternating stress causes fatigue crack formation and elongation. gear Gear reinforcement is a very typical and common application. Gears of any size and form can be improved by shot blasting/shot peening to improve the bending fatigue properties of the root of the tooth profile. The meshing of the teeth is similar to that of the cantilever beam. The load formed by the tooth surface contact produces a bending stress at the root position below the contact point Gears are usually shot blasting/shot peening after hardening. The increased surface hardness increases the compressive stress level proportionally. According to the process parameters, the maximum residual compressive stress of the gear after carburizing and shot blasting/shot peening can be in the range of 170-230 ksi (1170-1600 MPa). For enhanced carburizing gears, usually steel balls with a higher hardness (55-62 HRC). If you want to have less influence on the tooth surface, you can use a steel ball with a lower hardness (45-52 HRC), which will produce a compressive stress level of about 50% of the high hardness of the pellet. Introducing a compressive stress by hammering, grinding, honing, and vibrating varnish near the tooth surface line is the best way to enhance the fatigue resistance of gears. After the surface finishing treatment, the contact stress can be further reduced. Care must be taken not to cover more than 10% of the shot peening layer. The finishing of the shot peening small dents allows the contact load to be spread over a large surface area, which further reduces the contact stress. In the partial gear manufacturing process, after the controllable shot blasting/shot peening gear, the fatigue strength can be increased by 30% or more after 1,000,000 cycles. The following organization/specification standards confirm the use of controlled shot peening, a significant increase in flank bending load Lloyd's Register: 20% increase DNV: 20% increase ANSI/AGMA 6032-A94 Marine Gear Specifications: 15% increase link The connecting rod is an important part of the engine that transmits power. It changes the reciprocating motion of the piston into a rotational motion of the zone shaft and transmits the force acting on the piston group to the crankshaft. The connecting rod is mainly subjected to the alternating load generated by the gas pressure and the reciprocating inertial force. Therefore, when designing the connecting rod, it should first ensure that it has sufficient fatigue strength and structural rigidity. Obviously, in order to increase the strength and rigidity of the connecting rod, it is not possible to simply increase the structural size. As the weight of the connecting rod increases, the inertial force increases accordingly. Therefore, an important requirement of the connecting rod design is to ensure sufficient strength and rigidity under the lightest possible structure. That is, the lightweight design of the connecting rod is the ultimate design goal. The stress concentration of the connecting rod, that is, the most frequently occurring part, is transferred to the rounded corners on both sides of the I-beam near the center of the large hole. The index of the fatigue safety factor of the connecting rod is used to meet the design requirements of strength and stiffness, and the lightest economic optimization scheme is to carry out any boring machine processing before forging, casting or powder metallurgy connecting rod. Shot blasting/shot peening, which avoids the extra cost of shielding holes. No additional pre-treatment or post-treatment of the connecting rod is required before and after strengthening. Next page Installed on the washbasin, used to put cold water, hot water or a mixture of hot and cold water. Its structure includes: screw lift type, metal ball valve type, ceramic spool type, etc. The valve body is made of brass, chrome-plated, gold-plated and various metal lacquers. The shape is various, the handle has a single, double handle of the points. Some basin faucets are equipped with a drop lever, which can be lifted directly to open the washbasin drain and eliminate sewage. Wash Basin Faucet,Waterfall Basin Tap,Jaquar Wash Basin Tap,Jaquar Basin Tap Kaiping Jianfa Sanitary Ware Co.,Ltd. , https://www.jfsanitary.com
Shot peening to prevent bending fatigue of automobile parts