hello all, I had a katana I bought in 2001 and have since become an avid knife maker. but swords are beyond me so i had the blade sent out to be heat treated and see how things went. to make a long story short i choose a horrible place to do this and got my money back but it seems like the blade no longer has a curve and is perfect straight. can anyone explain what might had happened here? there's no hamon(at least as far as i can see). seems like a low end carbon steel. This was not a cheap knock off made in china but it was not a 10,000$ sword either. thanks for anyones time and help.