I bought a Chinese soldering iron and the tip broke real quick. I took then to buy 5 the Japanese brand tips Hakko. In the picture below we have only four tips, because a I had already used!
The tips have no protection, IE, We have to get hot and so save Tin tinned not to oxidize.
Are suitable for most soldering irons, including the Chinese I bought.
It's not solid, but has good resistance.
Below the photo of the tip seated in my soldering iron.
I bought a lot of them, Since when are very thin break easily. The good thing is that it's cheap! I leave the link:
http://www.dx.com/p/professional-900m-t-i-lead-free-soldering-iron-tips-silver-5-pcs-156152