日本金属学会誌

J. Japan Inst. Metals, Vol. 32, No. 6 (1968),
pp. 537-542

Effect of Composite Additions of Alloying Elements on the Strength of Iron-Boron Alloys

Masayoshi Hasegawa1 and Masafumi Okamoto2

1Metallurgical Department, School of Science and Engineering, Waseda University, Tokyo
2Graduate Student, Waseda University, Tokyo

Abstract:

The strength of C-free Fe-B alloys to which various alloying elements are compositely added in the `low-alloying' range have been investigated, and their strengthening phenomena are discussed. The boron contents in the specimens are 0.08 to 0.12%.
Fe-B alloys containing Nb, Mo or W in the range of 0.3 to 1.0% are strengthened by a bainitic-type transformation of austenite to ferrite at a faster rate of cooling than air-cooling (about 3°C/sec). Ni-Mn-Nb, Ni-Mn-Mo and Ni-Mn-W alloys are remarkably strengthened by this transformation and exhibit excellent hardenability. Fe-B alloys containing Nb or Mo, etc., e.g. Ni-Mn-Nb and Ni-Mn-Mo-Ti alloys, solution-quenched and tempered, show a high resistance to softening and precipitation strengthening of special boride.
The mechanical properties of Fe-B alloys containing about 2%Ni, 1%Mn and 0.5%Mn and 0.5%Nb, Mo or W are developed to the grade of 70∼78 kg/mm2 in yield strength, 76∼80 kg/mm2 in tensile strength and moderate reduction of area and elongation. The alloys solution-quenched and tempered at about 500°C have nearly the same strength as that of solution-quenching and improve their ductilities.


(Received 1967/12/8)

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