Tongs for tempering blades

[dickbrom]

I am a blacksmith working at a local museum. I came across an old pair  of tongs in their collection. The surface shows a little rust and lots of grain , typical of old wrought iron. It's clearly hand forged and massive. 

It's about 24 inches long overall. The bits are (each) one and a quarter inches square and about five inches long.  It's clearly designed for holding flat stock .

Can anyone suggest what these tongs were used for?  Possible for heating the spine of a blade ??

 

[Alan Longmire]

Pictures would help, but usually those are for soldering standing-seam roofing.  That's not to say you can't use them to temper stuff, but they're designed for soldering.