Effect of tempering on the strength and toughness of a series of Fe--Cr--Si--C alloys
The mechanical properties of a series of high strength Fe--Cr--C alloys with silicon additions of 1.5, 2.0 and 3.0 percent were determined for the as-quenched and the tempered conditions. Small additions of silicon to steel have been used in the past because it is a very potent solid solution strengthener of iron and it also increases the hardenability of steel. However, the unique ability of silicon to delay the decomposition of retained austenite and to prevent the precipitation of the embrittling cementite phase at intermediate tempering temperatures may be its most important function as an alloying element. By allowing tempering to take place at higher temperatures without the nucleation and growth of the non-coherent iron carbide, increased internal stress relief can be accomplished. The resulting combination of strength and toughness (210 ksi yield strength and 100 ksi..sqrt..in. fracture toughness) of these alloys, which was developed using a conventional quench and temper heat treatment, allows them to be classified near the high strength-high toughness band of the 18 Ni maraging steels. The fracture toughness of these alloys is higher than that of the current high strength, low alloy steels at the same strength levels. Results of the investigation show that iron alloys with superior properties can be designed from the metallurgical understanding of simple alloy systems. Supplemental adjustments to composition and heat treatment can then be made to optimize the desired mechanical properties.
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7339642
- Report Number(s):
- LBL-4574
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM STEELS
MECHANICAL PROPERTIES
AUSTENITE
FRACTURE PROPERTIES
HARDNESS
PHASE TRANSFORMATIONS
QUENCHING
SILICON ADDITIONS
SOLID SOLUTIONS
TEMPERING
ALLOYS
CARBON ADDITIONS
CHROMIUM ALLOYS
DISPERSIONS
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MIXTURES
SILICON ALLOYS
SOLUTIONS
STEELS
360103* - Metals & Alloys- Mechanical Properties