How to remove the gate of wear-resistant alloy steel

In order to save the cleaning process of riser castings, it is usually necessary to remove the riser first. The method of cutting off the riser is not only limited by the casting material, but also affected by the location of the riser and the size of its connection with the casting. Therefore, different cutting methods should be selected according to the specific conditions of production.

First, the knocking method for brittle materials (such as iron castings) and small iron platform risers or iron castings with smaller riser diameter or gate cross-sectional area can be directly knocked down with a hammer. If the contact section between the pouring riser and the casting is too large to be directly knocked off, it is best to select the sawing direction at the root of the pouring riser, saw it to a suitable depth, and then hammer it at one side of the sawing groove, so as to cut off the pouring riser conveniently and prevent the casting from being damaged. Pay attention to the tapping point and direction when tapping.

Second, gas cutting, gas cutting is a cutting method that uses the huge heat generated by the mixed combustion of combustible gas and oxygen to melt metal. For high risers on castings, oxyacetylene flame is generally used for cutting. The cutting time is arranged at normal temperature after sand cleaning and before heat treatment; For parts that are easy to crack, they are usually cut after heat treatment or special heating; High manganese steel castings are usually cut after heat treatment; Chromium-nickel steel castings shall be cut immediately after sandblasting cleaning. No matter which cutting method is adopted, the cutting should be completed at one time without stopping in the middle, so as to avoid local stress concentration at the root of the riser and cause cracks in the casting. Castings with a riser diameter greater than 500mm should be placed in the kiln for heat preservation and slow cooling immediately after the riser is removed. Oxygen, improve the melting temperature of incision and enhance the slag discharge ability. The cutting residual allowance of the riser on the machined surface of casting is determined by the diameter or width of the riser. The positive allowance is 1 and 30 of the riser diameter or width, and the negative allowance is 1 and 200 of the riser diameter or width. The riser of non-machining surface should be cut as flat as possible, and it can be cut again when the allowance after cutting is too large. The gas cutting equipment is simple, low in cost and high in efficiency, and can be used for cutting at various positions. Therefore, it is widely used to cut the riser of low-carbon steel and low-alloy steel castings with carbon content below 0.25%.

Third, sawing, the riser of copper alloy or aluminum alloy casting, because of its good toughness, is not convenient to be hammered off, and is often sawed off with a hand saw or a chainsaw.

Fourth, plasma arc cutting, plasma arc is a highly compressed and highly ionized arc. It has the advantages of high temperature, high energy density and controllable arc column. Plasma arc can cut all kinds of metal or nonmetal materials. At present, it is mainly used for cutting stainless steel and alloy steel castings and risers.