316L Seamless Stainless Steel Pipe

304 316L 316Ti 310S Seamless Stainless Steel Pipe
We produce seamless stainless steel pipe complying with specification A213, A269, A312, A511, stainless steel grades include 304, 304L, 316, 316L, 321, 347H, 310S, 904L, 2205, annealing pickling, bright annealing condition.

Seamless pipe is applied for General service, Curatorial Industry, Food and beverage Industry, Dorative and construct, Aerospace Industry, Chenmical and Petrochemical, Fluid transport, Water treatment, Boiler, heat exchanger, Oil and gas service, Mechanical and fabrication purpose.

Seamless Stainless Steel Pipe Specifications

Stainless Steel Grades

There are wide stainless steel material range for seamless pipes, containing Austenitic Stainless Steels, Ferritic Stainless Steels, Martensitic Stainless Steels and Duplex Stainless Steels, 304 / 304L and 316 / 316L grades are most used materials, other stainless steel grades are available.

TP316, TP316L Stainless Steel

TP304, TP304L Stainless Steel

Seamless Pipe Standard Specifications

Seamless Pipe Manufacturing Process

Seamless pipe is manufactured from steel round bar, the bar is heated and pierced to form a hollow billet, after removing oxide scale, billet is extruded into desired dimention using cold drawing and cold rolling methods, this technology can reduce outside diameter to smaller sizes, and control seamless pipe sizes and tolerances requirement, the inside of the tube can be controlled using a rod (known as rod drawing), a plug (known as plug drawing).

Billet

Billet is an extruded hollow tube from pilgered bar, it is actually semi finished tube, and it is needed inspection and pickling to ensure high quality.

Cold Rolling

Billet sizes are generally reduced to obtain thiner tube sizes, rolling process can achieve this purpose using compression.

Tube rolling is a very precise method of reducing very thin walled or smaller diameter tubes, usually it get a fine surface finish and accurate sizes.

Cold Drawing

Cold drawing is also cold working method to reduces the diameter by pulling the tube through a die, that device inner size is smaller than the tube, in order to pull the tube into the die, the diameter of tube is reduced to desired size to pass through.

Annealing

It is also named as heat treatment, this process soften material to make further processing, and improves the overall metallurgical microstructure of the tube.

Tube is heated to a controled temperate, usually 300 series stainless steel minimum annealing solution is 1040 C, annealing relieve stress and make material suitable redrawing.

Pickling

It is chemical method to clean the tube resulting from cold working or annealing process, generaal using sulphuric acid or nitric acid, putting tube into pickling tank and soaking a right time, not short and not long depending stainless steel grade.

Testing And Inspection

All the material should be tested before shipment as standard or special requirement, there are non-destructive and destrucative tests for option.

Non Destructive Testing

• PMI for material identity Visual inspectionDimensional inspection, tolerance Eddy Current testing Ultrasonic testing Hydrostatic pressure testing

Destructive Testing

Yield Strength, Tensile Strength,

Elongation

Rockwell Hardness testing

Grain size

Flattening and flaring testing

Seamless Pipe Advantages

20% Higher Working Pressures

Compared to welded tube, seamless pipe has no longitudinal weld seam, seamless tube has 20% higher working pressures under the same material and size condition.

Heavy Walls

Seamlless pipe can acheive heavy wall pipe for high pressure applications.