... Surface treatment:Carbon steel:Shot blasted, black painting, rust-proof oil, transparent oil,galvanizing,, hot galvanizingAlloy ... steel:Shot blasted, black painting, rust-proof oil, transparent oil, galvanizing,, hot galvanizingStainless steel ... Shipbuilding Jinan Shuangke Forging Machinery Co., Ltd. has an excellent design team and a highly efficient management team ...