Category: Casting And Welding

Bellows: This is used to blow out loose sand from the cavities and surface of the mould. Slick: Slick is used for repairing moulds. It is a small double-ended tool having a flat on one end and a spoon on the other. It is also available in various shapes. Lifters: Lifters are used for smoothing and cleaning out…

Refractoriness: Refractoriness is a property of moulding sand due to which it can withstand high temperature of molten metal without fusing and burning. Permeability: Permeability is ability of moulding sand to escape vapour and gases formed during pouring the molten metal into the mould cavity. Due to lack of permeability there may be casting defects like blowhole,…

Mould making is a process of creating a replica of casting with the help of patterns and moulding sand. The cavity, produced in sand body, facilitates the molten metal to solidify and to take the shape of the cavity. Various types of moulding sands used in a foundry are classified as follows: Green Sand: Green sand…

Solid Pattern/Single Piece Pattern: A single piece pattern is used for a simple casting. In this pattern, no joint or partition is used. It can be moulded in a single moulding box as shown in Figure 20.4. Figure 20.4 Single Piece Pattern Split Pattern: If design of the pattern is not simple, it is difficult to withdraw as a…

The surface finish of the casting product may not be as good as required, therefore, extra dimensions in the pattern are provided. The extra dimensions or extra materials provided for the pattern are known as allowances. The following allowances are provided for pattern making: Draft Allowance: To exit out the pattern from the mould easily, the…

Pattern is a replica of the product, which is to be manufactured through casting. It is used to make a mould cavity of required shape and size. Various types of pattern materials such as wood, aluminium, steel, plastic, and cast iron are used in sand casting. The selection of pattern materials is based on their…

Sand is the most suitable material for expandable mould. It has sufficient properties of moulding materials such as refractoriness, permeability, flowability, adhesiveness, cohesiveness, etc. Sand casting is the most versatile and common form of casting. In this method, a mould of sand with binding materials and water is prepared in which molten metal is poured…

A model of mould used in sand casting is shown in Figure 20.2. Moulding material that is packed around the pattern to provide the mould cavity is green sand. The various parts of mould can be defined as follows: Figure 20.2 A Model of Mould Used in Sand Casting Flask: It is a rigid box which opens at top…

Casting process can be classified on the basis of expandable mould and multiple-use mould as shown in Figure 20.1. Expandable mould is destroyed after solidification of the casting. But, multiple-use mould can be used to make many castings. Expandable mould is used for very complicated casting design. In this process, production rate is lower than the multiple-use…

Casting is an ancient manufacturing process. It had been used during 4,000–5,300 B.C. for manufacturing of copper arrowheads. In the field of casting, a number of modern technologies have been developed such as die casting, permanent mould casting, vacuum casting, continuous casting, electromagnetic casting, etc., but sand casting is one of the oldest casting technologies…