The design of the coating for diesel engine is as follows:
1 choose the type of coating.
It is the first problem to be solved whether the spray coating and spray welding layer have the principle difference in the upper part of the design or application.
(1) the spraying is mainly used for the workpiece with low binding strength, small impact load, friction and wear of lubricating metal, no deformation, failure to destroy heat treatment conditions, and larger circular workpiece, such as a variety of straight shaft and crankshaft journal, bearing, shaft bearing, diesel engine cylinder main bearing seat hole, cylinder liner, etc. The technology is better than the spray welding for the parent material. In addition to the general steel, it can also be used for some non sprayed materials, such as copper, aluminum and its alloys, and even plaster, plastic and wood can also be sprayed on the metal.
2. Spray welding should be used when the strength is high, or with abrasive wear, impact load, and wear medium. The spray welding is generally applicable to occasions where the thickness of the coating is not more than 2 mm, and the area of the spray welding is not too high. For small size workpiece, or large in size, it is only needed in some local spray welding, especially at the sharp corner. Spray welding is the most suitable for wear-resistant treatment.
Selection of 2 alloy powder.
It is necessary to choose the suitable gold powder according to the working condition and failure reason of the workpiece so as to obtain the best comprehensive effect.
3 coating thickness design.
The thickness of the coating can be determined according to the limit wear and machining allowance allowed by the workpiece. The processing allowance is usually about 0.2 millimeters. The thickness of the coating is generally not more than 1 millimeters. It is easy to shrink too much when the thickness is too thick. The spray welding layer can be slightly thicker but not more than 2 milli meters. It is not only difficult in process but also economically too thick. It's not good.
4 make technical conditions.
The main technical conditions include the designation of the type of coating, the thickness of the coating and the grade of the alloy powder, the specific requirements for the quality of the coating, the requirements for the processing after the spray, and the specific requirements and quality requirements for the heat treatment, and the requirements for the combination of the strength and the experimental methods.
