Reprint from Hardware & Fastener Components Magazine, Vol. 51

What are Tension Control Bolts?
Tension Control Bolts have a domed head, body, threads, and a splined tip known as the Pin Tail. (See Figure 1) Tension Control Bolts are part of the structural bolting family given by ASTM F3125. Like the other structural bolt variations, these come in two different types, regular and weathering steel and two different strength grades, 125,000 psi and 150,000 psi. The 125,000 psi version is considered Grade A325 and marked as A325TC or A325TC depending on whether it is Type 1 (regular steel) or Type 3 (weathering steel), respectively. The 150,000 psi version is considered Grade A490 and marked as A490TC or A490TC depending on whether it is Type 1 or Type 3, respectively.