WCN Spring 2012

S S Figure 3

S S Figure 4

Mechanical properties following wire drawing to 2.5mm diameter are given in Figure 5a and Table 3. In the drawn condition, the B steel exhibits the lowest tensile strength and elongation, the High B steel exhibits the highest tensile strength and higher elongation compared to the B steel. The Base steel exhibits similar uniform and total elongation compared to the High B steel albeit at a lower tensile strength. It should be recognised that failures

pearlite transformation kinetics may lead to increased lamellar spacing and/or coarser pearlite. One might also argue that the reduced strength level may be related to reduced solid solution strengthening. It should however be recognised that the B alloy does not exhibit strength reduction compared to the Base. It has been suggested previously that the strength reduction relates to an alloying effect on the austenite to ferrite1 or pearlite11 transformation.

by about 25 MPa was obtained. This strength difference cannot be ascribed to carbon as samples with the same carbon content were selected for testing. A higher tensile elongation was exhibited by the High B steel. It is interesting to note that reduced tensile strength with boron alloying is in agreement with earlier work on low1 and high7 carbon steels and is also in agreement with increased hardenability observed in the dilatometry study. Increased

S S Figure 5a

S S Figure 5b

UTS, MPa

UE, % TE, %

UTS, MPa UE, % TE, % 952 9.4 13.7 951 8.2 13.9 926 11.2 16.6

1644 1592 1677 1324 1317 1277

1.2 1.0 1.2 7.3 6.7 6.7

1.5 1.1 1.5 8.6 8.9 9.1

Base B High B

Drawn to 2.5 mm

Base B High B

Patented at 2.5 mm Base B High B

S S Table 2

S S Table 3

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WCN Issue N° 46 www.iwma.org