... -quality carbon steel.Quality and price is our vantage. glass curtain wall spider Casting: investment casting ,precision casting, lost ... , machining, turning, milling, drilling, thread cutting.Surface treatment: glass rays electrolytic polishing, coating, varnishing, bromzing. Passivating, grinding, polishingAnalysis ... metallograph.Quality control: According to ISO 9001 2001 glass curtain wall spider