 
                            
                            
                            
The common screw in the market is No. 45 steel, 40Cr steel (chromium plating), 38CrMoAIA nitriding steel. If your product is + glass fiber, it will fall off slowly after ...
                        
                        
                     
                   
                        
                              
                            
                            
                            
The common screw in the market is No. 45 steel, 40Cr steel (chromium plating), 38CrMoAIA nitriding steel. If your product is + glass fiber, it will fall off slowly after ...