Poor quality bi-metal Liebherr LPVD100 barrel copper layer

We always receive concerns from our customers about the quality of copper layer in our "Super Hydraulics" bi-metal barrels or cylinder blocks. The reason is that they had ever received some inferior quality parts from some Chinese companies whose copper layer of barrel was damaged after a very short time or run in a high pressure. You can refer to below pictures to see what the poor quality looks like. Maybe, some of friends have ever also met such troubles!

So, before their order, they want to get quality assurance that our Super barrels are perfect in the copper welding process. Hereby, we would like to explain the reason why it happened there and what our cylinder block quality is.

1, Reasons of damage or spalling of the copper layer:

The copper layer of this bi-metal cylinder block is made by “Powder Metallurgy Process” (The alloy copper powder is welded together with the steel matrix at a certain temperature and pressure). The advantages of this process are low cost and high efficiency; The disadvantages are that the welding strength of copper and steel is low, the copper layer is unreliable, and it will peel off at high pressure or high temperature, and the formula of alloy copper powder is varied and not wear-resistant. Because of low price, many Chinese manufacturers will give priority to this “powder metallurgy process” for the manufacturing of hydraulic cylinder blocks. This low-level welding process makes it impossible to produce a high-quality, stable and reliable Hydraulic Pump cylinder blocks. But, you maybe have your reason to purchase this kind of cylinder block as the price is really low, do you want to take the plunge and make a try?

2. High quality, copper layer never peels, excellent wear resistance of cylinder blocks from Super Hydraulics

Several years ago, we received many quality complaints like copper layer peeling off. In view of this, we never accept cylinders blocks which take the powder metallurgy processes. We require all our suppliers to purchase material which only take the "melting and casting process" (Alloy copper rods imported from Germany are welded together with a steel matrix at a certain temperature and pressure). The advantages of the "melting and casting process" are that the copper and steel welded body has high strength, the copper layer is very reliable, and it will never peel off at high pressure or high temperature, and the German copper is very wear-resistant, and the cylinder block made by "melting casting process" has a long service life; The disadvantage is high cost and low efficiency.

The following picture shows some technical parameters of the cylinder block of the "melting and casting process" and a microscope image of the welded copper layer:

A): The depth of copper and steel welding of  "melting and casting process" cylinder blocks

42CrMo+ZCuPb15Sn5 (uncorroded, 100x)	Copper-steel diffusion zone at depth 4.92 μm

 B): The lead particles in the copper layer are fine, uniformly distributed, and with a moderate eutectic phase 

ZCuPb15Sn5 (uncorroded, 100x)	ZCuPb10Sn10 (Corrosion, 200x)

 Mechanical properties of  "melting and casting process" cylinder blocks

1), The depth of the diffusion layer of copper molecules: More than 3μm

2), Shear strength: 42CrMo+ZCuPb15Sn5>120MPa; 45#+ZCuPb10Sn10>130MPa

3), Copper layer hardness: ZCuPb10Sn10>85HBW; ZCuPb15Sn5>60HBW

4), Steel matrix hardness: 42CrMo: (26~45)HRC 

Over 20 years of experience in Hydraulics and as a leading supplier for quality replacement hydraulic components and parts in China, we know hydraulics better and know how to control the quality and supply all our customer with the best quality and much competitive hydraulics products made in China. All hydraulic cylinder blocks of bi-metal sold by Super hydraulic are all strictly quality checked, only with "melting and casting process" to guarantee a high quality. The inferior barrels with "Powder Metallurgy Process”will never be supplied by Super Hydraulics. But, you have more than 70% possibility to get such poor cylinder blocks from other China hydraulic suppliers.

Kindly work with Super hydraulics and make Super be your reliable, valuable, one-stop hydraulics partner in China.