Cylinder series test, Mechanical Engineering

Assignment Help:

Cylinder Series Test

A series of round bars of various diameters are austenitized and quenched into oil or water. The bars are long sufficient hence the cooling of section at the middle of the length is not affected via the ends. After hardening every bar is cut in half and hardness measured on different points along a diameter. The graph in between distance and hardness from the centre is then prepared as in following figure. From such graph the diameter at that 50% of the structure is martensite is calculated. While such graph the diameter is plotted against bar diameter, this becomes possible to find out the bar diameter whether 50% martensite would form at the centre. This is termed as critical diameter for such quenching medium. Because the rate of cooling is less for oil quench after that for water quench, the critical diameter, of any type of steel will be less for oil quenching than for two water quenching. Quench severity is an index in which quantitatively explains the quenching situation. Such index indicated by H is explains as given ratio.

H = Heat transfer coefficient between steel and fluid/Thermal conductivity of steel

1409_Cylinder Series Test.png

Figure: Variation of Hardness along with Depth in Water-quenched Cylindrical Bars of (a) Plain Carbon Steel, (b) 1% Cr-V Alloy Steel

Obviously, when H → ¥, it shows the severest condition of quench, sense that surface of steel instantly reaches the quenching medium temperature. The critical diameter for that, an unrealizable and ideal situation is termed as ideal critical diameter. For infinite H-value ideal critical diameter and the critical diameter will be similar. For other H values the critical diameter will be slighter. Given figure illustrates the relationship in between ideal diameters and critical diameters for various H-values. Table no.10 illustrates relative values of H such can be acquired in different quench media beneath various condition along with value of one for still water as base.

1739_Cylinder Series Test1.png

Figure: Relation between Critical Diameter, Ideal Critical Diameter and Severity of Quench

Table no: Relative Quench Severities

Agitation of Quenching Medium

Movement of

Pieces

Severity of Quench

Air

Oil

Water

Brine

None

None

0.02

0.3

1.0

2.2

None

Moderate

-

0.4 - 0.6

1.5 - 3.0

-

None

Violent

-

0.6 - 0.8

3.0 - 6.0

7.5

Violentor spray

-

-

1.0 - 1.7

6.0 - 12.0

-


Related Discussions:- Cylinder series test

Force analysis, explain with suitable eg. static and dynamic force analysis...

explain with suitable eg. static and dynamic force analysis

Isentropic flow through the nozzle, Isentropic flow through the nozzle: ...

Isentropic flow through the nozzle: In an isentropic flow through the nozzle, air flows at rate of 600Kg/hr. At inlet to the nozzle, the pressure is 2Mpa and temperature is 1

THERMO, WHAT IS SPECIFIC HEAT

WHAT IS SPECIFIC HEAT

Feedwater controls for steam generator, Q. Feedwater Controls for Steam gen...

Q. Feedwater Controls for Steam generator? associated with that Steam Generator. The flow controllers utilize regular P.I.D. controllers, and their outputs are fed directly to

Determine the period of its oscillation, What are the various methods for c...

What are the various methods for calculation of Natural frequencies? Illustrate one of them. A cylinder of diameter 100 mm and mass 1 Kg floats vertically in a liquid of mass de

Carnot vapour cycle, how to understand what is carnot vapour cycle???please...

how to understand what is carnot vapour cycle???please understand me..??

Material requisition for quotation procedure, The Mechanical Design Enginee...

The Mechanical Design Engineer/Specialist shall be responsible for mechanical design calculations that are required to ensure that the end product complies with all applicable code

Explain about vertical vessels, Q. Explain about Vertical Vessels? Vert...

Q. Explain about Vertical Vessels? Vertical vessels shall normally be designed as self-supporting units, and shall resist overturn based upon wind or earthquake considerations.

Find the maximum allowable size of the milling cutter, Find the Maximum All...

Find the Maximum Allowable Size of the Milling Cutter  Find the maximum allowable size of the milling cutter if it is to rotate at 65 rpm while the cutting speed is 20 m/min.

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