It is reported that the manufacture of seamless nickel-steel-titanium tees is a highly challenging technology.Cutting and welding methods cannot produce seamless tees,and machining methods are energy-consuming and material-wasting,only suitable for the manufacture of tees with smaller sizes and specifications.Cold extrusion and end-reducing methods are the essence of tee manufacturing.Cold extrusion utilizes metal flow from both ends to the middle to obtain the material required for the convex end.The material for the convex end required by the end-reducing method is already present,and the excess material at both ends thickens the end.The end-reducing method has a low yield but small metal flow variation,which is conducive to successfully manufacturing tees from materials with insufficient plasticity.

Due to the poor room temperature plasticity of titanium,hot processing with end reduction is adopted for tees above DN50.For tees below DN25 made of nickel,steel,and titanium,forging and machining methods are used.Nickel and steel have good room temperature plasticity,so cold extrusion and end reduction are adopted for tees above DN50.In large batches,bulging presses with higher production efficiency can be used,while in smaller quantities,die-set unidirectional cold extrusion is adopted.For large-sized products with smaller quantities(generally referring to those above DN15),end reduction is used,while cutting and welding are only suitable for situations where product requirements are not high.

The manufacturing of seamless tees is limited to products with certain thicknesses,and suitable manufacturing methods for very thin-walled products have not yet been found.

In general,different manufacturing methods should be adopted for different materials,specifications,sizes,and batches.Currently,there is no ideal processing method for tees between DN25 and DN50.Research and development personnel are developing a new process that will produce nickel-titanium tees of this specification range with high quality.