Abstract: A method for preparing a negative pressure film-covering frozen sand mold includes: directly obtaining a mold cavity of a sand mold through numerically controlled machining of a frozen sand blank; covering a surface, brushed with a thermal insulation coating, of the mold cavity of the sand mold with a softened thin film, and covering an outer surface of the sand mold with a back film to seal a sand box; fixing the frozen sand mold in an air extraction sand box with a vacuum chamber, and extracting air through a vacuum pump, so that the thin film tightly adheres to the sand mold through vacuum suction force; and closing the box to obtain an integral sand mold, and pouring a casting at room temperature or low temperature under negative pressure. The method is environment-friendly, and the prepared frozen sand mold has high strength and is convenient for sand cleaning.

Abstract: A method for preparing a negative pressure film-covering frozen sand mold includes: directly obtaining a mold cavity of a sand mold through numerically controlled machining of a frozen sand blank; covering a surface, brushed with a thermal insulation coating, of the mold cavity of the sand mold with a softened thin film, and covering an outer surface of the sand mold with a back film to seal a sand box; fixing the frozen sand mold in an air extraction sand box with a vacuum chamber, and extracting air through a vacuum pump, so that the thin film tightly adheres to the sand mold through vacuum suction force; and closing the box to obtain an integral sand mold, and pouring a casting at room temperature or low temperature under negative pressure. The method is environment-friendly, and the prepared frozen sand mold has high strength and is convenient for sand cleaning.

Abstract: A TiB2 rod, and a method of fabrication therefore are is provided. It may be used to producing a TiB2 coating on the tip surfaces of a resistance spot welding (RSW) electrode, such as may be of a type for welding applications in automotive, and electronic industries. There may be a rod of material for coating the tips of welding rods that includes TiB2 ceramic having good electrical and thermal conductivities and a high melting temperature. The new TiB2 rod may be used to produce a TiB2 coating on an electrode tip surfaces by ESD, which may tend to be low in cost and which may tend to produce a higher electrode life as compared to an embodiment of TiC coating.