Materials Education Training and Learning

(METaL)

PRACTICAL METALLURGY

Notes by Dr J Spittle

Practical Metallurgy Course Assessment (55%)

Name:

2

Metallographic investigations

1) On the iron carbon phase diagram below mark the position of the steel grades EN1A (0.1wt% C), EN8 (0.45wt% C), 0.76 wt% C and 1.0 wt% C.

4 marks

2) Using the lever rule calculate the predicted microstructure of each grade in the two-phase region just below the Eutectoid temperature (excluding 1.0 wt% C as this requires different calculations).

Grade Total Ferrite Total Cementite Pro-eutectoid ferrite

Pearlite

EN1A – 0.1 wt%.C

EN8 0.4 wt%.C

0.76 wt%.C

12 marks

3

3) Sketch and label the microstructures of the each steel grade in the area below.

EN1A EN8

EN8WQ 0.8 wt%.C

1.0 wt%.C

10 marks

4) Make observational comments of the microstructures commenting on different phases and the effect of grain size on mechanical/other properties

10 marks

4

Mechanical Testing

5) From the data gained from the tensile tests produce tensile curves for each of the steel samples. 16 marks

6) Using the tensile curves extrapolate data to complete the table below

Sample Yield Stress UTS Strain to FailureEN1A EN8 0.8 wt.%.C1.0 wt.%.C

12 marks7) Using data from the hardness tests complete the table below

Sample Hardness (Hv)EN1A EN8 EN8 WQ0.8 wt%.C1.0 wt%.C

5 marks

8) Plot curves of hardness vs. carbon content, yield stress vs. carbon content and UTS vs. carbon content. 9 marks

9) Comment on the mechanical properties of the different specimens. In your discussion comment on the relationship of the microstructure and C content to the observed properties. Reference should also be made to non-equilibrium cooling ………………………………………………………………………………………………………………………………………………………….

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5

SEM

10) Produce SEM images of the fracture surfaces of the tensile samples EN1A and 1.0 wt.%. C.2 marks

11) Make observational comments on the fracture surfaces of each of the sample EN1A and 1.0 wt.%.C 4 marks………………………………………………………………………………………………………………………………………………………….

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6

EDX

12) Using the data provided, complete the table below to match the zinc coating type to the sample

Coating SampleHDGGalfanMagizincGalvanealZintec

5 marks

13) Which of the samples have a phosphate coating on it? 1 mark

Quantitative Metallurgy

14) Using the mean linear intercept method complete the table below for each sample 2 marks

Sample Grain Size1a1b

7

Microstructure Grain Size Measurement

Sample 1a.

8

0.05mm

Sample 1b.

9

0.05mm