ME 328 HARDENABILITY LABJOMINEY END QUENCH TESTSEYI ADENIYANEMAIL: OAA302@MAIL.USASK.CA

SAFETYGeneral SOP must be adhered to

All phones switched off

Good housekeeping

Emergency exit doors

All students must appear in appropriate PPE

HARDENABILITY Hardenability is the ability of an alloy to be hardened by the formation of martensite

as a result of a given heat treatment.

Hardenability test is used to determine the influence of alloy composition on the

ability of steel alloy to transform to martensite for a particular quenching treatment.

Remember: Hardenability is not Hardness!

JOMINY END QUENCH TEST

TEST PROCEDURE1. The specimen is austenitized at a prescribed temperature for a prescribed time.

2. The specimen is quickly removed from the furnace.

3. Then it is placed into Jominy End Quench unit.

4. The lower end is quenched by a jet of water with the specific flow at 24˚C.

5. After cooling to the room temperature, the specimen is ground along the length.

6. The Rockwell hardness measurements are made: 1/16 in intervals for the first 1/2

in and 1/8 in intervals for the remaining 1.5 in.

7. The hardenability curve is obtained when the hardness is plotted as a function of

position from the quench end.

HARDENABILITY CURVECooling rate decreases,

hardness decreases

(100% Martensite)Quench end is cooled most rapidly, maximum hardness

EFFECT OF ALLOY COMPOSITION ON STEEL

Plain Steel (0.4% wt Carbon)

Alloy steels (0.4% wt Carbon),

different alloying element

Identical hardness at quenched end

Hardness is function of carbon content

Low hardenabilityHardness drops sharply after

a short Jominy distance

Gradual decreases in hardness

More hardenability

Quenched end(Cooling rate 600˚C) 100% Martensite

Pearlite with proeutectoid Ferrite

Mixture of Martensite and Bainite

Effect of Carbon Content

The hardness at any Jominy position increases with the concentration of

Carbon

The hardenability curves depend on :carbon content

Microstructure and Indentation point on the Sample Specimen

1045 Steel (300 gf)Reading Distance

from end (mm)

D1 D2 D ave. VHN Approx. HRC

1 1.6 29.34 28.63

2 3.2 30.75 30.68

3 4.8 32.27 31.66

4 6.4 40.67 38.68

5 8 43.14 42.81

6 9.6 44.22 44.36

7 11.2 44.38 44.9

8 12.8 45.83 45.49

9 16 45.82 45.71

10 19.2 46.3 46.71

11 22.4 46.49 46.44

12 25.6 46.69 46.42

13 28.8 47.68 45.79

14 32 47.24 47.38

15 35.2 47.71 46.69

16 38.4 47.38 48.12

17 41.6

18 44.8

19 48

TABLE OF VALUES