How to produce thin wall stainless steel tube?

 

What is thin Wall Tubing?

Thin Wall Tubing Thin wall tubing is precision tubing that typically ranges from . 001 in. (. 0254 mm) to about . 065 in. Deep-drawn seamless tubes are made from metal blanks in multiple deformation processes. They can be used for different industrial purposes and the manufacturing of metal bellows. Common materials for the production of our seamless metal sleeves and thin-walled tubes are stainless steels. Those materials come with different attributes that have to be considered in the selection to perfectly meet the application’s requirements.

 

How is stainless steel tubing made?

The tubing is manufactured through an extrusion process where the tube is drawn from a solid stainless steel billet and extruded into a hollow form. The billets are first heated and then formed into oblong circular molds that are hollowed in a piercing mill.

 

How deep-drawn thin wall seamless tubes are made?

The production of our thin-walled tubes starts with a metal strip that undergoes several sheet metal forming processes.

1. Hot rolling line to punch the stainless steel tube blank
2. Either soap or oil is used for each operation as lubricantto ensure smooth movements
3. Depending on the used material and the designated final size of the tube, it has to be deep-drawnthrough multiple dies with decreasing diameter, wall-thickness decreases
4. Annealing(in vacuum furnaces) after each plastic deformation process to restore the elasticity of the material

Special washing machines are used continuously in order to achieve an immaculate surface.

If thin-walled stainless steel tubing is requested, our customers benefit of efficient multi-drawing technologies. we follow a sustainable approach. Due to our closed water circuits, eco-friendly technologies, and installed oil traps, we ensure that no pollutants are released into nature.

 

why thin wall stainless tubes with very low tolerances?

We are specialized in the manufacturing of seamless tubes with extremely thin wall-thickness. To guarantee a leak-free welding line with the “weld-end”, a consistent dimensional accuracy of the wall is needed. As an experienced precision bellows manufacturer, we are able to hold such very low tolerances, ensuring max. 0.1-0.4 mm tolerance in diameter and 0.004- to 0.015 mm in wall-thickness. The hydraulic presses allow maximum production lengths of up to 450mm and diameters of ca. 70mm. The closed bottom of our seamless cups and tubes can be designed in customized shape and also the open side may be formed to meet individual requirements. It is also possible to create holes in the bottom – for example stainless steel cups (bonnets) as housing for measurement and controlling devices

 

Seamless vs. welded precision tubing

Seamless thin walled metal tubes up to 450mm length

While it is often almost impossible to distinguish a seam-welded from a seamless tube with the naked eye, there are some significant differences of stainless steel tubes that matter when it comes to ultra-precise applications. Welded tubes are made from a roll-formed metal strip. The welding process results in an inhomogeneous tube wall that has to be reworked first. Due to different working standards, the quality of the weld area can show great variances in the final product, resulting in a lesser reputation for welded tubes compared to seamless tubes. Since deep drawn seamless tubes are intermediate products in our manufacturing of metal bellows, we do only provide results in a smooth and homogeneous surface. Our seamless precision bellows are key components in highly sensitive systems. Their spring rate must exactly meet the requirements, e.g. for actuators and sensors in cars and aircrafts around the world,

 

Why Thin Wall Thickness Tubes Difficult To Produce

Why it is difficult to produce stainless steel seamless tubes with thin wall thickness?

We get one order on June 13th, 2014, Stainless Steel Seamless Tubes, ASTM A213 TP304, Outside Diameter size in 23mm, Wall Thickness in 1.19mm, minimum wall thickness, length in 16400mm and 16650mm, Bright Annealing. The total quantity in 7 tons. At first, I treat this order as small order. The expected finished time is within June 30th. But after we start the production, I find it is not so easy as it looks like.In order to ensure the stainless steel tubes quality, we can’t compress our production period. July 7 – 8th is the earliest time we finished the production.Even it is only 7 tons tubes. base on below reasons, the production velocity very slow:

1. Wall thickness of the steel tubes very thin. The speed of cold rolling should be controlled. Only 500KG/day, so that LG-30 cold rolling cost 14 days!
2. The length of steel tubes longer than 16000mm. The handle for degreasing will be slow.
3. Shipment of condition of the steel tubes in bright annealing. (If Pickle annealing, we can choose cold drawn, cold drawn will be much sooner than cold rolling.)
4. Outside diameter size of the tubes in 23mm, it is non-conventional size. We need make a new molding, and we only have 1 molding, because it is only 7 tons, we need save cost for our customer.

Base on above reasons, the production speed very slow. By the way, if you have orders with OD size 23mm, we can produce for you in lower cost and high quality. Because we have OD 23mm cold rolling molding, the molding cost more than USD 1200. So we can cold rolling the tubes for you.Base on the same reason, we have 16mm, 18mm, 19mm, 19.05mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 25.4mm, 26mm, 27mm, 28mm, 30mm, 32mm cold rolling molding etc.