Heat Treatment of Steel

Case Study # 91358

Physics

Examines a process that increases the hardness of steel.

1,354 words () | 3 sources | MLA | 2004 Philippines

Paper Summary:

When steel is heat treated, the size and morphology of its phases are changed. The samples used in this paper are AISI 1045 and 4140 steels. Four samples each of AISI 1045 and AISI 4140 are shown to be subjected to annealing and quenching while eight samples of AISI 1045 are subjected to tempering. Photomicrographs and hardness of each sample are taken. From the results, the paper shows that quenching increases the hardness of steel and increasing the cooling rate increases the hardness of the sample due to the formation of fine grains of pearlite. Increasing the tempering temperature reduces the hardness of a specimen. The paper includes graphs.

Paper Outline:
Introduction
Experimental Section
Results and Discussion
Conclusion
References

From the Paper:

"Theoretically, a quenched specimen should be harder than tempered specimens. This is due to the interstitial carbon atoms that deter dislocations along the lattice. The relatively higher hardness of a quenched specimen may also be attributed to the few slip systems of the BCT crystal structure. From the microstructure, the trapped carbon atoms are evident as the black regions."

Sample of Sources Used:

Callister, W.D. Materials Science and Engineering: An Introduction. John Wiley and Sons, Inc. ; 2001.
Shackelford, J.F. Introduction to Materials Science for Engineers. 5th ed. New Jersey: Prentice-Hall, Inc.; 2000.
Dieter, G.E. Mechanical Metallurgy. McGraw-Hill Inc.