Mainly in the lower jaw plate, especially in the next 1/3 of the most serious wear and tear, the upper is less wear and tear. Tooth surface of the tooth after grinding to lose the ability to tear, can not be used. Under the scanning electron microscope, it was found that the surface of the tooth plate was extruded into a concavo-convex shape, and then the abrasive was pressed to form a pressure-bonded surface. On the grinding surface, a lot of abrasive filaments were observed, See the tooth surface micro-cracks.
(1) reason analysis: wear is normal, but in a short time jaw plate wear failure, it is not normal.
The main reasons are:
① material properties such as fragility, hardness, material size, density, etc. have changed, and the shredder did not make timely adjustments;
② the angle between the movable jaw plate and the fixed jaw plate door is increased by more than the normal range (18 ° ~ 22 °)
③ eccentric shaft speed too fast, moving jaw plate swing too many times, has been shredded the material too late to all the discharge, resulting in tearing cavity clogging phenomenon, accelerated jaw plate wear;
④ jaw plate material is not suited to their own strength and wear resistance, poor impact resistance or jaw plate and body surface contact is not smooth.
① for each batch of machine into the material sampling, found that the nature of the material have a more substantial fluctuations, the timely adjustment of the main parameters of the shredder, such as clamp angle, eccentric shaft speed, output and motor power, so that with the machine Shredded material to adapt to reduce the wear of the jaw plate.
② new jaw plate to keep tight, and to ensure that the jaw plate and the body (moving, static jaw) surface contact smooth. Can be padded between the two surfaces of a layer of pliers, plywood, cement mortar and other plastic materials better. The assembly of the jaw and jaw is required to align the crest of one jaw to the jaw of the other jaw, ie the movable jaw is in a substantially engaged state with the fixed jaw.
③ jaw plate to use high hardness material to resist the extrusion micro-cutting failure; use a sufficient toughness of the material to resist the impact of chisel impact fatigue failure. Usually use manganese containing 12% to 14% of high manganese steel (ZGMn13) cast into a jaw plate. Small metal shredders can also be made with white cast iron jaw plate, while the tooth plate structure to improve and reduce the relative sliding of the material and the tooth plate. As the jaw plate is usually made up and down symmetrical shape, it can be in the minor repair when the lower part of the jaw has been worn up over use. Large metal shredder jaw plate is made of a few pieces, can be used interchangeably to extend the life of the jaw plate.
④ has a mine shredding process of cement enterprises, the mine can be crushed and the cement plant crushed the same type of wear jaw plate to each other to replace the new jaw plate to continue to play a role, without having to abandon the old.
⑤ For the wear and tear of the jaw plate, can be used surfacing method, so that tooth recovery. Repair can be used arc welding, can also be used automatic submerged arc welding.
A) Mn13 cast steel jaw plate repair. Commonly used electrode for the D256, D266, D276, D277 and so on. Selection of special wear-resistant electrode, the effect is better, such as WC tungsten carbide electrode, TDO 3 heat-resistant wear-resistant electrode. Surfacing should take "small current, small bead, discontinuous" surfacing method, that is, a certain length of the weld in the red bar that is quickly hammer with a hammer to reduce the shrinkage stress, with the welding with water, rapid cooling, Improved abrasion resistance.
B) Repair of non-Mn13 material jaws. Can be used to fill the welding wire welding materials, such as 50Cr3, 13Cr13 and so have achieved good results.