Question

What are different types of gates? Explain them with the help of sketches stating the relative merits and demerits of each.

Answer 1

the ca are used to feed molben metal into Different types of gates are- 6 Top gate 1. cope Бол " A top gate some times also called as Drop gat because s Top gabe. the molten metal just chops on the sand in the bottom of the mould, sgt in generally located in cope. Merits :- 0 Genuation of favorabe temperature gradients to enable directional solidification from the - casting towards the gats which serves as rise to - It is used for ferraus material. ③ Time required to fill the cauity in comparitively less so it can be used for material howing low fludity. Demerits :- o Droppicy metal can erode the mould suface - leading to casting difect. ③ There is a lot of furbulenco.

& Bottom gates sgt is located in drag paction of mould. - cope Drain "In bottom gate liquid metal rapidly fills baltom cauty portion of acanity and rises stedily and gently up mould walls baltom gate. Merits In compaision to top gale, baltom gates involves little tubulence and sand erosion. ③ at produces good casting surfaces . It in genually used for non-ferrous alloys, I Demuits 1 It creates unfavourable tempuatu gradien and makes difficults to achiew directional Solidification. " lo 4 freezing takes place from boltom, it could I chake the metal flow before the mould is full @ filling time of canity in relatively high.'

6 Parting line y in this type some portion of the mould cawty is below the parting line and some paction is about parting line. I Canity above parting line will be filled by assuming bottom gate and parting line below partion will be filled by top gate. Thus combining characteristics of both top gate and bottom gate