光洁的

C-timber has no knots in it.

木料没有节疤。

Compared with that of furane resin bonded sand,the feasibility of phenol resin bonded sand in forming a uniform coating layer in the inside mould surface is studied as well.

本文分析究了砂在铸型中成型条件及内表面形成机理，并对比究了覆膜和呋喃自硬砂在铸型内表面形成匀覆砂层可行性。