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

Determine the maximum stress developed in the beam, Determine the maximum s...

Determine the maximum stress developed in the beam: An I section in Figure is utilized as a beam. The beam is subjected to a bending moment of 2.5 kN m at its neutral axis. De

Determine the maximum uniformly distributed load, Determine the maximum uni...

Determine the maximum uniformly distributed load: A timber beam 150 mm wide & 300 mm deep is supported simply over a span of 4 m. determine the maximum uniformly distribute

Autocad help menu-options buttons-coordinate system, AUTOCAD HELP MENU ...

AUTOCAD HELP MENU In this section it will show the Drawing objects its will have some predifined oblects that will help , with some Lectures  notes .It also having options as s

Thermodynamics., First law of thermodynamics applied to flow process

First law of thermodynamics applied to flow process

Urine preservatives - specimen collection, Urine preservatives - Specimen c...

Urine preservatives - Specimen collection: Urine preservatives : preservatives have different roles but are usually added to reduce bacterial action or chemical decompo

Brittle fracture, Dear Sir I would to know what is the min. time required...

Dear Sir I would to know what is the min. time required for carbon steel tube A214 @ zero C to 50 C

Road under special conditions, Road under Special Conditions: Roads pa...

Road under Special Conditions: Roads passing through difficult terrain and environmental conditions require special attention in design, construction and maintenance. The foll

Evaluate the natural frequency, (a) Evaluate the natural frequency of syste...

(a) Evaluate the natural frequency of system shown in figure and show that it will be equal to (b) calculate equivalent stiffness of two springs connected in parallel.

Explain the lip clearance angle - angle of drills, Normal 0 fal...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Calculated the diameter of an aluninium shaft , Calculated the diameter of ...

Calculated the diameter of an aluninium shaft: Calculated the diameter of an aluninium shaft that is designed to store the similar amount of strain energy per unit volume as a

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