Boiler Steel Pipe

Boiler Steel Pipe Production process

Boiler Pipe Manufacturing methods

The manufacturing method of medium and high pressure boiler steel pipe is same with the seamless steel pipe, but there are some key manufacturing processes shall be noted:

Fine drawing, surface bright, hot rolling, cold drawn, heat expansion

Heat treatment methods applied in the boiler pipes

Heat treatment is a method of changing the physical properties of high pressure boiler pipe by heating and cooling. Heat treatment can improve the microstructure of high pressure boiler pipe, so as to meet the required physical requirements. Toughness, hardness and wear resistance are obtained by heat treatment. In order to obtain these characteristics, it is necessary to adopt quenching, annealing, tempering and surface hardening.

1. Quenching

Hardening, also called quenching, is that high pressure boiler pipe is heated evenly to the appropriate temperature, then quickly immerse in water or oil for rapid cooling, and cooling in the air or in the freezing zone. So that the high pressure boiler pipe can obtain the required hardness.

2. Tempering

High pressure boiler pipe will become brittle after hardening. And the stress caused by quenching can make the high pressure boiler pipe tapped and broken. The tempering method can be used to eliminate brittleness. Although the hardness of high pressure boiler pipe is lighter reduced, its the toughness can be increased to reduce the brittleness.

3.Annealing

Annealing is the method to eliminate the internal stress of high pressure boiler pipe. The annealing method is that the steel parts need to be heated to the critical temperature, then put in dry ash, lime, asbestos or closed in the furnace, then let it cooling slowly.

We can produce all sizes of boilers tubes,according to European,Chinese,American,Japanese standard.With fast delivery time,supportive payment term.All tubes production processes are controlled strictly.with high level of quality requirement,all tubes are inspection before delivery,and also accept third party inspection before delivery.

Test

The Steel Pipe Should Be Tested Hydraulically One By One. The Maximum Test Pressure Is 20 MPa. Under The Test Pressure, The Stabilization Time Should Be Not Less Than 10 S, And The Steel Pipe Should Not Leak.

After The User Agrees, The Hydraulic Test Can Be Replaced By Eddy Current Testing Or Magnetic Flux Leakage Testing.

Nondestructive Test：

Pipes That Require More Inspection Should Be Ultrasonically Inspected One By One. After The Negotiation Requires The Consent Of The Party And Is Specified In The Contract, Other Non-Destructive Testing Can Be Added.

Flattening Test：

Tubes With An Outer Diameter Greater Than 22 Mm Shall Be Subjected To A Flattening Test. No Visible Delamination, White Spots, Or Impurities Should Occur During The Entire Experiment.

Hardness Test:

For Pipe Of Grades P91, P92, P122, And P911, Brinell, Vickers, Or Rockwell Hardness Tests Shall Be Made On A Specimen From Each Lot

Bend Test:

For Pipe Whose Diameter Exceeds NPS 25 And Whose Diameter To Wall Thickness Ratio Is 7.0 Or Less Shall Be Subjected To The Bend Test Instead Of The Flattening Test. Other Pipe Whose Diameter Equals Or Exceeds NPS 10 May Be Given The Bend Test In Place Of The Flattening Test Subject To The Approval Of The Purchaser

Packaging

There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.Our packing can meet any needs of the customers.

• Plastic caps plugged at the two sides of pipe ends
• Should be avoided by the steel strapping and transport damage
• Bundled signs should be uniform and consistent
• The same bundle(batch) of steel pipe should be came from the same furnace.
• The steel pipe has the same furnace number, the same steel grade, the same specifications.