Category: Casting And Welding

This process was developed by Carthias in France and mainly used for ornamental products. A definite amount of metal is poured into an open ended mould, and a close-fitting core is forced into the cavity, causing the metal to be forced into the mould cavities with some pressure. The core is removed as soon as…

This is a special type permanent mould casting in which hollow casting is prepared without core since solidification of molten metal starts from mould surface towards centre. The molten metal is kept inside the mould cavity for a pre-determined time for solidification of particular thickness and then the mould is turned down. The rest of…

In this casting method, metallic moulds are used which can withstand the high temperatures of molten metal. The permanent mould is made into two parts; both parts are hinged at one end and clamped at other end. Mould is pre-heated before filling the molten metal. After solidification mould is opened and casting is removed. Again…

Following sand testing are used in foundry. Moisture Content Test: To find the moisture content in sand, moisture teller equipment is used. It consists of cast iron pan and an infrared heater bulb fitted in a shade. Twenty grams of sand is taken in a pan and it is exposed in infrared heater for 2–3 min.…

Core is a sand body specially prepared in a core box and it is used to form a cavity/hole/recess or projection in a casting for different purposes. As core is surrounded by liquid metal from all the sides, it has to have better characteristics than the moulds. Better raw sand and binder are used for…

Sometime, it is impossible to use core print to support the core. In this case, a metallic support is used which is known as chaplet. Chaplet is made of same material as the material of casting. It gets fused with molten metal. Chaplets are placed in a mould between the mould face and the core…

Chills are used to improve the directional solidification with faster heat conduction by metallic chills; solidification is initiated and accelerated at desired locations. The thinner section of a casting solidifies earlier in comparison to thicker section, which results in distortion, internal stress set up, crack etc. Chills increase the solidification rate in thicker section and…

A network of passage of molten metal from pouring basin to mould cavity is known as gating system. It consists of pouring basin, downsprue, skim bob, runner, gate, riser, etc. A good gating system should have the following properties: Types of Gates Figure 20.16 Types of Gating Systems Risers Risers are provided in mould to feed…

At first, pattern is placed on moulding board, which fits the flask being used. The lower moulding box is placed on the board with the pin down as shown in Figure 20.15 (a). Moulding sand, which has previously been tempered, is filled over the pattern. The sand should be pressed around the pattern with the fingers…