risers, Electrical Engineering

Risers:

Riser Design : A riser or a feeder head is a passage of sand made in the cope to permit the molten metal to rise above the highest point in the casting after the mould cavity is filled up. Risers serve a dual function. They compensate for solidification shrinkage which is a very common casting defect and are a heaf source so that they freeze last and promote directional solidification.

Types of Risers : There are two types risers :Top or open risers and side or blind risers.

Riser shape and Size : The metal in the riser should remain in the molten state for a longer time than in the mould cavity.

It means a heaf looses in riser should therefore be kept to a minimum. It means a riser most freeze more slowly than the casting. Those there shape should be such as to give volume-to-surface-area ratio a maximum value. This ratio is maximum for a sphere. Therefore this is the ideal shape of a riser.

As regards the height of the riser, it must be fall enough to ensure that any pipe formed in it does not penetrate the casting.

Melting Furnaces for Ferrous Metals : Various types of melting furnaces are used in different foundary shops, depending upon the quality of metal to be melted of a time and the nature of work that is carried out in the shop. Converters, open hearth and electric furnaces for melting iron and steel are the example of some melting furnaces.

Posted Date: 2/8/2013 5:09:46 AM | Location : United States







Related Discussions:- risers, Assignment Help, Ask Question on risers, Get Answer, Expert's Help, risers Discussions

Write discussion on risers
Your posts are moderated
Related Questions
Mainframes Computers larger than minicomputer more power  operating at very high speed  called  mainframes.  They  can processes 64  bit data.  Such computers are used  in defe

A quantizer has 130 quantum levels that exactly span the extremes of a symmetrically ?uctuating message with step size δv = 0.04 V. Determine the following: (a) |f(t)|max.

Determine phase - voltage and power: A balanced star connected load is supplied from a symmetrical 3-phase 440 Volt system. The current in each of the phase is 40 Amp and lags

When MT 2 is Negative  and g is positive In this  case  gate  current  flows  through  junctions P 2 N 2   electrons  are injected from  N 2   layer to  P 2   a result  junct

What are the advantages of modern ac generators and Integrated Drive Generators? There are two questions here. I''d really like it if somebody could help me. I''m an AE student.

Q. DTL AND TTL LOGIC CIRCUITs? Bipolar transistorswere the first solid-state switching devices commonly used to implement digital logic circuits in the 1950s and 1960s. These c

radiation pattern optimization of a planar array antenna using BBO

Q. Explain state-variable techniques? The matrix formulations associated with state-variable techniques have largely replaced the block-diagram formulations. Computer software

Q. Need of Microphone in telephone hand set? Microphone: For all practical purposes, microphone is transmitter for telephone. The microphone converts acoustical signals in the

the depletion layer in the pn junction is caused by