Chrome plated hollow bar is also known as chrome plated tube, it is very important material for many different industries, they are widely used to produce hydraulic cylinder and penumatic cylinders with honed cylinder tubing and some other accesorries. Besides this, chrome plated rods can be produced to Linear shafts for different machines. This product is made of steel round bars, but how is it manufactured in details? Here this article briefly introduces the manufacturing process of chrome plated bar.
Step 1. Purchase qualified raw material-Steel round bars
The raw material for chrome plated hollow rods are steel tubes. Usually the chrome plated hollow bar manufacturer will buy the steel tube from the tube manufacturers. Some chrome plated hollow bar supplier its self is a tube manufacturer.
There are many different steel grades of the steel bars to make different chrome plated bars, including SAE 1020, CK45, ST52 /E355 / ST52.3, 42CrMo, SAE4140, and so on.
After get the raw material, the factory need to inspect the raw material quality to make sure the raw material without any defects, which will lead the defects on the finished product.
Step 2. Get the steel tubes heat treated as per customers’ request.
Heat treatment is very important to chrome plated bar, with heat treatment, the mechanical properties will be greatly increased, for the chrome plated hollow bar, the heat treatment type is usually stress relief heat treatment.
Step 3. Cutting the raw material hollow bar into lengths
If the required length for the chrome plated tubes are with fixed length, the factory needs to calculate the length of the raw material and cut it to length and control the tolerance on length +/-2mm.
Step 4. Straightening the hollow bars
Step 5. Peeling on the steel hollow rods
To roughly remove the Scale and other Surface Defects by peeling.
Step 6. Straightenning
Step 7. Grinding the steel hollow rods
Grinding the steel rods to the dimensions close to the finished dimensions.
Step 8. Straightening the ground hollow bars.
Step 9. The second grinding process
Step 10. Polishing on outer diameter surface
Polish on the diameter of the steel hollow bar to make the hollow bar to the required dimensions and the the surface roughness of Ra 0.2μm to 0.4μm, to get the hollow bar prepared for chrome plating.
Step 11. Chrome plating
Hard chrome plating the steel hollow bar to a certain chrome plated thickness, such as min. 20 microns, 25 microns, … 50 microns. After chrome plating, the steel hollow bar now can be called chrome plated hollow bar or chrome plated hollow rod or chrome plated tube.
Step 12. Final polishing
Here is the finishing polishing on the chrome plated outer diameter of the steel tubes (hollow bars), to make the surface super smoothly, the roughness can be as good as Ra 0.2 microns (10RA).
Step 13. Final inspection
Do final inspection of the chrome plated hollow bars, the inspection including dimension, straightness, surface roughness, hardness, chemical composition, and mechanical propterties.
Step 14. Packing the finished chrome plated hollow bars.
The finished qualified chrome plated hollow rods need to be well packed to prevent from any damages during moving, loading, transportation and unloading. Usually the chrome plated hollow rods are light oiled and packed with cardboard sleeves to protect the outer surface. After that, they will be put into wooden cases or packed in bundles for further transporation.
Here below is the manufacturing process flow chart of the chrome plated plated hollow bar.
