Price of large diameter stainless steel pipe

Seamless steel pipe is divided into two types: hot rolled and cold rolled (drawn)

Hot-rolled seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

In addition to general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, cold-rolled (pulled) seamless steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, Stainless thin-walled steel pipe, special-shaped steel pipe. The outer diameter of the hot-rolled seamless pipe is generally greater than 32mm, and the wall thickness is 2.5-75mm. The diameter of the cold-rolled seamless pipe can reach 6mm and the wall thickness can reach 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.

Classification of stainless steel pipes: stainless steel pipes are divided into two categories: seamless steel pipes and seamed pipes.

For stainless steel pipes under fluid pressure, hydraulic tests should be carried out to check their pressure resistance and quality. If there is no leakage, wetting or expansion under the specified pressure, it is qualified. Some steel pipes also need to be crimped according to standards or requirements of the buyer. , flaring test, flattening test, etc.

Generally used seamless steel pipe: it is made of 10#, 20#, 35#, 45# and other high-quality carbon steel 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 40MnB and other alloy steel hot-rolled or cold-rolled. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transportation pipelines. 45#, 40Cr and other medium carbon steel seamless pipes are used to manufacture mechanical parts, such as the stressed parts of automobiles and tractors. Generally, seamless steel pipes are used to ensure strength and flattening tests. Hot-rolled steel pipes are delivered in hot-rolled or heat-treated state; cold-rolled steel pipes are delivered in heat-treated state.

The key production process of large diameter stainless steel pipe is as follows:

1. Plate inspection: After the thick steel plate used for the production of large-diameter steel pipes enters the production line, the first full plate ultrasonic inspection is carried out;

2. Edge milling: According to the edge milling machine, both sides of the thick steel plate are cut on both sides to make it achieve the specified plate width, plate edge flatness and weld appearance;

3. Pre-bending: Use a pre-bending machine to pre-bend the edge of the sheet so that the edge of the sheet has a specified refractive index;

4. Forming: On the JCO forming machine, half of the pre-bent thick steel plate is first passed through the stepping motor stamping die for several times, rolled into a "J" shape, and then the other half of the thick steel plate is bent into a "C" shape. " shape, resulting in an "O" shape with an open mouth;

5. Welding treatment;

6. Testing in all aspects;

7. Diameter expansion: Expand the total length of the submerged arc welded straight seam steel pipe to improve the specification accuracy of the steel pipe and improve the distribution of thermal stress of the steel pipe.