a. Shrinkage/expansion forming

The reduction forming process of the large and small heads involves placing a tube blank with the same diameter as the large and small ends into a forming die, and pressing it along the axial direction 

of the tube blank to make the metal move along the mold cavity and shrink into shape. According to the size of the reducer, it can be divided into one-time compression forming or multiple compression

forming.

B. b Stamping forming

In addition to using steel pipes as raw materials to produce large and small heads, some specifications of large and small heads can also be produced using stamping forming technology with steel 

plates. The shape of the punching die used for stretching is designed according to the inner surface dimensions of the head, and the steel plate after cutting is stamped and stretched into shape using 

the punching die.

Before bonding the large and small ends, dry cloth should be used to wipe the socket side and the outer side of the socket. When there is oil stains on the surface, acetone should be used to wipe it 

clean. The following points should be noted:

1. Control caliber: DIN standard (DN10-DN150), 3A/IDF standard (1/2 "-6"), ISO standard（ Ф 12.7- Ф 152.4);

2. International industrial standards: DIN, ISO, SMS, 3A, IDF, etc;

3. Product materials: stainless steel 304, 316, 316L;

4. Quality and purpose: The large and small heads are treated with polishing equipment both inside and outside to meet surface requirements; This product is suitable for industrial fields such as dairy, 

food, beer, beverages, pharmaceuticals, cosmetics, etc;

5. External processing: non-standard products can be processed according to user requirements through drawings and samples;

6. Connection methods: clamp (quick fit) type, welding type, threaded (union) type.

Note that the large and small ends are also suitable for reducing the diameter of pipelines in the environmental dust removal industry. Generally, they are made by cutting and welding steel plates, 

and the diameter of the pipes varies. The materials are usually hot-rolled coils, which are very well applied and can save costs.