The manufacturing process of seamless steel pipes involves several steps to produce a seamless tube without any welded seams. Here is an overview of the typical manufacturing process:

Raw Material Preparation:

The process starts with selecting and preparing raw materials, usually solid round steel billets or solid steel ingots.

Heating:

The raw material is heated in a furnace to a forging temperature. This temperature is crucial for proper forming and ensures the material is malleable enough for subsequent processing.

Piercing:

The heated billet is pierced at the center to create a hollow shell called a "bloom."

Rolling:

The bloom is then processed through a mandrel mill to reduce its diameter and wall thickness while increasing its length.

Sizing:

The pipe passes through a series of sizing rolls to achieve the desired outer diameter and wall thickness.

Cooling:

The pipe is cooled either by air or water to stabilize its dimensions and properties.

Straightening:

The pipe undergoes a straightening process to correct any distortions and ensure its straightness.

Cutting:

The pipe is cut to the specified lengths using cutting machines.

Testing and Inspection:

Various tests are conducted to ensure the quality of the seamless pipe, including non-destructive testing, dimensional inspection, and surface inspection.

Finishing:

Surface treatment processes such as pickling, passivation, or coating can be applied depending on the intended application of the seamless steel pipe.

Final Inspection and Packing:

The finished seamless steel pipes undergo final inspection to meet quality standards before being packed and shipped to customers.

This process results in seamless steel pipes that are uniform in structure and free from welds, making them suitable for high-pressure applications, critical environments, and industries where a smooth interior surface is required.