By swnorris
Date 03-12-2008 20:34
Edited 03-12-2008 20:36
Tom,
The carbon content you mentioned at .3 is within the A706 spec. and also within the range in Table 5.2 of D1.4, which indicates that very little preheat is needed, so it really isn't high by rebar standards. Carbon equivalency can be calculated as CE = % C + %MN/6 + % CU/40 + % Ni/20 + % CR/10 - % Mo/50 - % V/10. In general, the CE of A706 is controlled to provide a carbon equivalent not to exceed 0.55%, so preheat is usually not needed on bars up to 3/4" in diameter. On the other hand, for A615 rebar, the CE generally falls between 0.6 and 0.7% and preheat is almost always required.