Show general properties of castings, Mechanical Engineering

Assignment Help:

Q. Show General Properties of Castings?

1. Fe-Cr (10-30%Cr) alloys offer good resistance to oxidation, low strength at elevated temps, restricted to use in oxidizing or reducing conditions that involves low static loads and uniform heating.  Chromium content depends on anticipated service temperature.

2. Fe-Cr-Ni (> 13% Cr, > 7% Ni, {%Cr > %Ni}) alloys are similar to above except they have greater strength and ductility than the straight Cr alloys. These alloys are also used to withstand greater loads and moderate changes in temperature, and in oxidizing and reducing gases that are high in sulphur content.

3. Fe-Ni-Cr (> 25% Ni, > 10% Cr, {%Ni > %Cr}) alloys are used where there is no appreciable content of sulphur, they do not carburize or become brittle and do not take up nitrogen in nitriding atmospheres. The service life of castings, increases with increasing Ni content in carburizing or nitriding atmospheres used extensively under conditions of severe temperature fluctuations.

4. Nickel-base (³ 50% Ni, appreciable amounts of Cr, cobalt (Co), and refractory metals, little or no Fe, possibly some Al and Ti) heat resistant alloys have superior corrosion resistance and mechanical properties superior to other alloys.  50Cr-50Ni and 60Cr-40Ni are used for supports and other firebox fittings due to their resistance to hot-slag corrosion in boilers that fire oil high in vanadium content.  Hot slag high in vanadium pentoxide (V2O5) is extremely destructive to most other heat-resistant alloys.

5. Cobalt-base alloys (³ 50% Co, plus appreciable Cr and refractory metals) have good high-temperature mechanical properties.  They are not as strong as Ni-base alloys in short-time tests but are competitive in combined strength and corrosion resistance with Ni-base alloys at high temperatures and for long periods of operation.


Related Discussions:- Show general properties of castings

Fermenter dimensions and mechanical design, Once the total volume of an ind...

Once the total volume of an individual vessel has been established the detailed dimensions or mechanical design can be performed. Much of this is based on "Rules of Thumb"  built f

Corrosion - erosion allowance, Q. Corrosion - Erosion Allowance? The re...

Q. Corrosion - Erosion Allowance? The required design life shall be based on written agreement between the user and the Engineering Contractor. Allowance specified shall be ba

Advantage of electro chemical machining, Advantage of Electro Chemical Mach...

Advantage of Electro Chemical Machining 1. As the tool does not come in contact with the work there for tool wear is practically nil. 2. The metal removal is faster rate.

Describe the elements of polyhedral objects, Describe the Elements of Polyh...

Describe the Elements of Polyhedral objects Objects that are often encountered in engineering applications can be classified as either polyhedral or curved objects. A polyhedr

Find the maximum shear stress - stepped circular bar, Find the maximum shea...

Find the maximum shear stress - stepped circular bar: A stepped circular bar ABC 4 m long fixed at one of the end 'A' is subjected to a torque of 10 kN-m. If the portion AB is

Mechanics of solid, determine crippling load for T section dims 12cm??12cm?...

determine crippling load for T section dims 12cm??12cm??2m and of length 6m it used as colum with one of its end fixed and other hinged E=2??10 power 5 N/mm2

CUPOLA FURNACE, With the help of neat diagrams explain various parts of Cup...

With the help of neat diagrams explain various parts of Cupola. Define its operation. How the thermal efficiency of Cupola calculated?

Annealing temp, hiw can i fix the maximum temp of the aluminium

hiw can i fix the maximum temp of the aluminium

Characteristics of adhesives and adhesive joints, Characteristics of Adhesi...

Characteristics of Adhesives and Adhesive Joints While an adhesive joint is created this has to show individual or several of given properties. (a) Mechanical strength again

Thermal reservoir - thermodynamics, Thermal Reservoir - Thermodynamics: ...

Thermal Reservoir - Thermodynamics: Thermal Reservoir. A thermal reservoir is the part of environment that can exchange heat energy with system. It has adequately large capa

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd